Research Article
S. Mohammadi; M. Azizi; J. Vaezi
Abstract
Introduction: Thyme is a perennial plant belongs to Lamiaceae. Thymus is a well–known medicinal plant, native to Southern Europe and its essential oil is manufactured commercially for use in cough drops, mouth-washes, liniments, toothpastes, detergents and perfumes. The herb is approved by Commission ...
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Introduction: Thyme is a perennial plant belongs to Lamiaceae. Thymus is a well–known medicinal plant, native to Southern Europe and its essential oil is manufactured commercially for use in cough drops, mouth-washes, liniments, toothpastes, detergents and perfumes. The herb is approved by Commission E in the treatment of bronchitis, whooping cough and upper respiratory inflammation. The Thymus genus comprises over 300 species of which, 18 are found in Iran, which grow wild in many regions and four of them are endemic. There are serious difficulties in the taxonomical interpretation of the taxa belonging to the genus Thymus owing to the high variability of populations with respect to many morphological and micro-morphological traits. The morphology and different components of essential oils in different species of Thymus are variable due to hybridization and polyploidization, despite its rare self-pollination. In general, intraspecific hybrids of the genus Thymus seem to possess intermediate morphological characteristics and composition of essential oil in comparison with the relevant characteristics of the parent plants. The accumulation of the essential oil takes place in gland hairs, which are distributed on the surface of the epidermis of the aerial parts of the plant. The content of the essential oil can depend on origin, climate, harvest, as well as drying and storage conditions. By carefully examining the structural, phenotypic, chemical and genetic aspects of the natural populations of a plant, it is possible to select either them or samples from them as an important step in the process of breeding the desired medicinal plant.
Material and Methods: In order to have a comparison microscopically and morphologically characteristics of Thymus vulgaris, two landraces of Thymus transcaspicus were studied in completely randomized design with four replications at the faculty of Agriculture in Ferdowsi University of Mashhad. Inflorescence length, number of flowers per inflorescence, shoot height, leaf, bud and flower length, leaf width, the largest diameter of canopy, weight, fresh and dry herb yield, percent of essential oil, distinct and type of trichomes, were measured. For glands morphological and structure analysis leaves were processed according to conventional techniques for scanning electron microscopy (SEM). In order to obtain comparable results the leaves from the third node of the apex were used for SEM analyses. Leaf samples were fixed in glutaraldehyde and paraformaldehyde. After being dehydrated, they were coated with gold in the vacuum evaporator. Finally, the preparations were observed and photographed with a KYKY-2800B SEM.
Results and Discussion: The ANOVA of the data showed that there was considerable variation for all studied characters. Results of mean comparisons showed that the highest height, the largest diameter of canopy and percent of essential oil were for T. vulgaris. Maximum inflorescence length, number of flowers per inflorescence, leaf, bud and flower length, leaf width, was also recorded for T. transcaspicus. Results of essential oil (EOs) analysis by GC/MS showed that thymol and carvacrol were the major compounds of all EOs samples, with highest and lowest content observed thymol and carvacrol in T. vulgaris (64.75 and 6.78 %). T. vulgaris produced more essential oil as compared to another thyme species. Two types of glandular trichomes are distributed on the outside surface of leaf, namely, peltate ones (PGTs) and capitate ones (CGTs). The glandular hairs of Lamiaceae likely release various secretions, such as the essential oil and polysaccharide. When trichomes got matured, essential oil could be found on all of the glandular trichomes on aerial organs of Thymus. Besides essential oil, what else trichomes could secrete needs further study.
Conclusion: The essential oil is highly complex chemical compounds. The content and composition of it vary depending on season, growing conditions, and plant species. High essential oil content is related to a much secretion of glandular trichomes. An application for variety protection was filed for ‘T. vulgaris’, now recommended to producers in Mashhad interested in a thymol-rich thyme. We can carry out a selection program to optimize quality and yield of thyme (T. transcaspicus L.) landraces, with used of T. vulgaris and crossing with clones of T. transcaspicus.
Research Article
S. Karimpour; Gh. Davarynejad; M. ZakiAghl; M.R. Safarnejad
Abstract
Introduction: Micropropagation is important for both multiplication and preservation of a wide range of nursery plants, including many fruit crops. A number of studies exist on optimization of growth in in vitro condition for one or two cultivars, but often these results cannot be used for the other ...
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Introduction: Micropropagation is important for both multiplication and preservation of a wide range of nursery plants, including many fruit crops. A number of studies exist on optimization of growth in in vitro condition for one or two cultivars, but often these results cannot be used for the other genotypes because individual cultivars may differ greatly in their requirements. Therefore, genotype-specific medium are usually empirically developed for many plants including pear. Pear cultivars and species are often recalcitrant to tissue culture manipulations and Murashige and Skoog (23) (MS) basal nutrient medium at full or half strength or with slight modifications is the most media were used. The QL, DKW, and WPM media are also used and they differ mostly in types or amounts of calcium and nitrogen in compared with MS. Developing growth media for specific and unique cultivars is complex and time-consuming. Currently, improved experimental design and using statistical softwares allow much more efficient approaches to be utilized for the improvement of micropropagation media and conditions. Improving of growth medium for in vitro propagation of plants depends on type and quantities of mineral nutrients and plant growth regulators as important ones. The existence of statistical softwares to manage effective factors is very needed to access an optimized growth medium for in vitro propagation of plants. Design Expert is used as auxiliary software to identify essential factors in in vitro culture. Since the in vitro proliferation parameters of Pyrus communis cv. ʽShekariʼ need to optimize for growth better, we were designed and performed a multifactor surface response experiment by Design Expert software to following two goals. First, to find optimized amount of some elements in medium and second, to show the response surface method can be useful for improving in vitro culture.
Materials and Methods: One experiment was designed by Design Expert software and was performed to improve in vitro proliferated shoots of Pyrus communis cv. ʽShekariʼ. Shoots were grown in a modified MS medium (supplement with 1 mg l-1 of N6-benzyladenine) were used for this experiment. The experiment was included 20 model points randomly based on three nutritional factors: NH4NO3 (0.5-1.5×), Fe (0.5-1.5×) and micro nutrients (1-2×) in different concentration of their MS amounts. Media enriched with sucrose (30 g l-1) and agar (8 g l-1) after pH adjustment at 5.7. Cultures were grown at 25°C under a 16-h photoperiod with 70–90 μM m-2 s-1 irradiance provided by a combination of cool- and warm-white fluorescent bulbs and were transferred to new medium every 3 weeks. Several responses were recorded after two months: Proliferated shoot number, proliferated shoot length (cm), total leaf number, leaf chlorophyll a (mg g-1), leaf carotenoids (mg g-1), and vegetative growth (cm). Responses for each point were the mean of 5 replicates. Experimental design, model evaluation, and analysis were done by Design-Expert® 8 (2010) software and the highest-order polynomial model that was significant for each response was used for ANOVA.
Results and Discussion: Factors statistically were significant for responses according to ANOVA in linear, 2FI and quadratic models. Reduced NH4NO3 (×0.5) and enhanced Fe (×1.5) induced the higher number of proliferated shoots up to 4.43 folds of control according a quadratic model. NH4NO3 and Fe×Micro had negative liner relationships with shoot length, while leaf number negatively was affected by micros. Fe and NH4NO3 were effective factors on leaf chlorophyll a and carotenoids contents. Increasing Fe (×1.5) and decreasing NH4NO3 (×0.5) led to 2 folds higher production of chlorophyll a and carotenoids. Vegetative growth of Pyrus communis cv. ʽShekariʼ in a quadratic-order method (negatively controlled by NH4NO3 and micros) increased by high values of proliferated shoot number and shoot length induced by reduced NH4NO3 (×0.5). Optimized amount of three studied factors based on two important responses, maximum amount of proliferated shoot number and length, were 0.9, 1 and 0.5× for Fe, micro and NH4NO3 in MS medium, respectively.
Conclusions: Design Expert software and response surface method were used successfully for in vitro optimizing of Pyrus communis cv. ʽShekariʼ regenerated shoots. Fe, Micro and NH4NO3, were the effective factors for shoot regeneration responses in linear, 2FI and quadratic models. The multifactor investigation in surface response design will enable us to predict an optimal medium for several effective factors and estimate suitable responses. Outputs of these types of experiments provide a suitable background to increase optimization accuracy for future experiments.
Research Article
F. Dezhabad; M. Haghighi
Abstract
Introduction: Most plants, especially those that are native to hot areas, show signs of injury when exposed to low temperatures. Damages caused by cold stress occurs at the cell and organs level, which reflects it at the plant surface. Color change, chlorosis, general reduction of growth, cellular tissue ...
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Introduction: Most plants, especially those that are native to hot areas, show signs of injury when exposed to low temperatures. Damages caused by cold stress occurs at the cell and organs level, which reflects it at the plant surface. Color change, chlorosis, general reduction of growth, cellular tissue destruction, non-absorption of nutrients, reduction of photosynthesis, non-transferring photosynthetic materials are from early effects of cold stress. Cellular responses to colds including loss of thoracic pressure, vacuolization, collapse of cytoplasmic membrane balance, cytoplasmic flow loss, and general organ dysfunction. The susceptibility of the plant to frost is different depending on the type of plant, variety, tissue morphology and other cellular characteristics, as well as the cold conditions of the period, time and cold intensity. In addition, it seems that organs of the plant have different degrees of cold tolerance. If the temperature of the aerial part is favorable, the low temperature of the root zone can be one of the factors limiting the root system and plant growth. The consumption of balanced boron content by neutralizing the negative effects of cold stress and mechanisms such as maintaining the structure of the membrane, improving and increasing root growth, increasing the synthesis of proteins needed for the plant, adjustment of stomatal movements and improved stomatal conductance, increased cell division, increased nitrogen metabolism and chlorophyll production, and its consequence was increased photosynthesis and dry matter production, increased activity of antioxidants, calcium / potassium ratio adjustment, optimizing the transfer of calcium in the plant, adjusting the amount of water and conducting it in the cell, increasing the moisture content and relative content of leaf water, transferring soluble materials and increasing water use efficiency creates a relative resistance to low temperature stress. Although the root temperature is very effective in plant growth, it has been less attractive. Therefore, the aim of this study was to investigate the effect of low temperature of root and shoot on the ability to restore plant growth and physiological activity in the presence and absence of boron.
Materials and Methods: In order to compare the impact of sudden low temperature stress of root and shoot on recovery of vegetative and physiological traits of tomato, a research was conducted in two separate experiments under controlled conditions in the greenhouse of Faculty of Agriculture, Isfahan University of Technology. Two experiments were factorial based on completely randomized design with 10 replications including two concentrations of boron (0, 0.5, 1 and 1.5 in ppm) and two temperature levels of shoot and root sections (10 degrees’ Celsius temperature, and 11 rootstock temperatures and 22 ° C optimum and control temperatures). Indicators included photosynthesis rate, respiration rate, stomatal carbon dioxide, stomatal conductance, chlorophyll fluorescence, chlorophyll index, water use efficiency, proline, antioxidant, phenol secretion from root and leaf extracts, leaf relative water content, soluble protein concentration, ion leakage, leaf water potential, root and shoot dry weights and starch content. Finally, the analysis of the results was done by statistical software statistic and comparing the meanings by LSD test at 5% level.
Result and discussion: The results showed that the highest amount of photosynthesis, root dry weight and dry weight of the aerial part were in the consumption of 0.5 ppm of boron during abrupt stresses of low temperature on the root after the recovery period. The highest amount of stem proline and electrolyte leakage were also obtained from 0.5-1.5 ppm of boron consumption during abrupt low temperature on the shoot part. According to the results, it was found that when stress has entered from the root zone to the aerial part of the plant, the plant was in the better conditions after the recovery period. It seems that when a cold stress occurred on the roots, the plant can produced more antioxidant substances, including phenol and proline, while counteracting the relative water content of the leaves were more effective with radical agents. Thus, in normal conditions, the roots of the plant operated at a lower temperature than the airspace. They also exhibited more adaptations to the lower air at the lower temperature than the air section and the plant is less damaged. At levels above the boron element due to the effect of boron toxicity and the production of excess free oxygen radicals, the plant probably suffered more severe damage than cold damage.
Conclusions: Sudden low temperatures stresses on the root and shoot had negative effects on the recovery of the vegetative and physiological traits of tomatoes. When lower temperatures were imposed on the shoot, the plant suffered much more damages. Consumption of 0.5 ppm of boron during cold stress by creating optimal conditions for growth also caused the relative neutralization.
Research Article
B. Abedi; T. Parvaneh; E. Ardakani
Abstract
Introduction Apple is one of the most important horticultural crops in Iran. The aim of this study was to investigate the effect of genotype on physical and chemical properties of fruit; to evaluate the amount of fruit secondary metabolites and correlation between them with the enzymatic browning in ...
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Introduction Apple is one of the most important horticultural crops in Iran. The aim of this study was to investigate the effect of genotype on physical and chemical properties of fruit; to evaluate the amount of fruit secondary metabolites and correlation between them with the enzymatic browning in some Iranian apple cultivars. Recently red-fleshed apples have been attracted the attention of many researchers and fruit marketers because the flesh of those cultivars contains a high amount of red pigment anthocyanins, which show strong antioxidant activity. These cultivars have a better place in the market for the consumers because of the attractiveness, quality and high levels of anthocyanins and other phenolic compounds in fruits. Development of such new varieties with unique properties is important for improving the apple breeding and processing industry in the world. Phenolic compounds and flavonoids are products of the phenylpropanoid pathway. They are secondary metabolites and are responsible for different functions in the plant life cycle. Secondary metabolites play an important role in the quality of food (color, flavor, and odor). Also production of secondary metabolites may be a part of the plant defense system. Materials and Methods The fruits of ‘Morabaee-Mashhad’, ‘Top Red Delicious’, ‘Golab Kohanz’, ‘Winter Banana’, ‘Golab-e Kermanshah’, ‘Early Devan’ and ‘Pepin’ apple cultivars were harvested manually from trees at commercial maturity stage in Mashhad city, and ‘Red-flash’ apple cultivar was harvested in Shahrood city (Bekran Village), Iran. Fruits were transported to the laboratory soon after harvest. The measured chemical properties were consisted of total soluble solids (TSS), titrable acidity (TA), TSS: TA, total phenol content (TPC) and Antioxidant. Titratable acidity (TA) was determined by Korean models GMK855 and reported g 100 g-1 of malic acid. Total soluble solids (TSS) was determined at 20 ◦C with a refractometer and reported as ◦Brix. The pH value of fruit was measured with a pH meter at 20◦C. The pH differential method was used to determine the total anthocyanin content. The absorbance of the solution was measured at 510 nm. The total phenolic content was determined by a modified Folin-Ciocalteu reagent method. This experiment was conducted according to the completely randomized design; with thirty replicates. Data were analyzed statistically by SPSS statistical software and differences among means were determined for significance at p < 0.05 using Duncan’s multiple range test. Results and Discussion The highest and lowest of enzymatic browning was found in ‘Pepin’ and Red-flash apple cultivars, respectively. Red Delicious, Macintosh, and Liberty showed high levels of enzymatic browning. According to some researchers, there is a strong correlation between the amount of browning and total phenol content of apple varieties "Empire", "Rome", "Golden Delicious" and "Delicious"(oseteng and Lee 1987; Milani and Hamedi 2005). San et al. (2002) revealed that there was a direct correlation between fruit phenolic content and antioxidant activity in 11 fruit species, indicating a significant contribution of phenolic compounds in the antioxidant activity of fruits. The results showed that the effect of cultivar on physic-chemical properties of fruit was significant at 5% probability level. The concentration of total soluble solids was significantly affected by cultivar, the highest concentration of total soluble solids was observed for Red-flesh apple cultivar while the lowest was recorded in Golab-e Kermanshah. Red-flesh and Golab-e Kermanshah cultivars had the highest and the lowest anthocyanin contents andthe highest and lowest of pH values were observed in Red-flesh and Golab Kohanz cultivars, respectively. The highest concentration of total phenolics was observed for Morabaee-Mashhad while the lowest was seen in Early Devan cultivars. The correlation between the enzymatic browning and antioxidant capacity of fruits was -0.507*. Conclusions The present research confirms that Red-flesh apple cultivar as a native fruit has been of interest to researchers and consumers because of its high amount of soluble solids, anthocyanins and flavonoids content, high level of antioxidant capacity and having a specific flavor and taste. Therefore, it can be a worthy cultivar for apple breeding programs and development in future.
Research Article
A. Angooti; J, Hajilou; F. Razavi
Abstract
Introduction: The ability to tolerate cold will not be possible without stopping or inducing sleep, which is one of the important steps in the life cycle of plants in temperate regions. This period is one of the important factors in preventing cold damages in winter and spring in temperate regions. Various ...
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Introduction: The ability to tolerate cold will not be possible without stopping or inducing sleep, which is one of the important steps in the life cycle of plants in temperate regions. This period is one of the important factors in preventing cold damages in winter and spring in temperate regions. Various studies in controlled conditions on plants have shown that in plants, when entering and leaving this period, various changes occur in materials such as proteins, enzymes and hormones. In order to control the harmful effects of active oxygen species, plants have defense mechanisms. Catalase, peroxidase and superoxide dismutase enzymes are a defensive team whose common goal is to defend against the destructive effects of active oxygen species. This study was carried out to determine the chill requirement and its relationship with the changes in the activity of antioxidants enzymes and proline.
Materials and Methods: The experiment was conducted at agricultural Research Station of Khalat-Pooshan and the Laboratory of Flower Biology and Physiology of Fruit Growth in the Department of Horticulture, Faculty of Agriculture, Tabriz University in 2015-2016. Flower buds needed for testing were selected from ‘Siah Shabestar’, Zard Mashhad, Zoodras cultivars and a local genotype of sour cherry. Once a month, enough buds were harvested and until the experiments began, they were kept inside the freezer inside an aluminum foil at -80 ° C. In order to estimate the chill requirement, four replicates (4 geographic directions) from each cultivar and from each replication four branches with the same length and diameter were removed. The amount of chilling accumulation and chilling requirement in each month was calculated according to Utah model. In order to estimate fresh weight, four replicates in each cultivar were selected and in each replication five buds were selected from different parts of the branch. The statistical design used in the determination of the chill requirement was a randomized complete block design. Enzymatic and proline data were analyzed in a completely randomized design as factorial
Conclusions: Chill requirement: Based on the Utah model, the chill requirement of sweet and sour cherry cultivars contains Zard Mashhad, Zoodras and Siah Shabestar were calculated 752, 780, 867 and 961 CU, respectively. There was a significant difference in the activity of superoxide dismutase enzymes between cultivars and different sampling times at 1% probability level. Siah Shabestar cultivars with the highest chill requirement had the lowest SOD enzymatic activity and Zard Mashhad and Zoodras were intermediate cultivars in terms of enzymatic activity. Sour cherries, which had the least chill requirement, showed the highest levels of SOD enzyme activity. This is consistent with the results of some researchers regarding apricot stated that the low chill apricot cultivars had the highest SOD enzymatic activity. The sour cherry had the highest amount of POX enzymatic activity with the least amount of chill requirement, and also Siah Shabestar has the least chill requirement. Like the two previous enzymes, the activity of catalase was highest in sour cherries and the lowest was observed in Siah Shabestar. In terms of the presence of free proline, there was no significant difference between the Zard Mashhad cultivars and Zoodras, while there was a significant difference between these two cultivars and Sour Cherry and Siah Shabestar. Zoodras cultivar has the highest and our cherry has the lowest amount of free proline. Between different cultivars, in terms of fresh weight of buds, there is a significant difference at 1% probability level before and after placement in the growth chamber. The increase in fresh weight of sour cherry and Zard Mashhad, Zoodras and Siah Shabestar cultivars were 25, 27, 31.5 and 33%, respectively. The highest fresh weight before and after placement in growth chamber was observed in Siah Shabestar and sour cherry was the lowest. In all the cultivars, the activity of all three enzymes were initially at maximum (369 CU), then, with the cooling of the air and the initiation of deep dormancy, the activity of these enzymes were greatly reduced (820 CU) and then again increased in the activity of this enzyme (963 CU), which is similar to other studies.
Conclusions The results of this study showed that the antioxidant metabolism in plants is influenced by seasonal cycle changes and enzymatic activity changes depending on temperature, so that sour cherry with the least chill requirement has the most activity of the enzyme catalase, peroxidase and superoxide dismutase and Siah Shabestar, which have the most chill requirement, have the least enzymatic activity. Accordingly, the enzymatic antioxidant system activity of the flower buds was relatively high at the beginning of the dormancy period, but decreased during the end of dormancy. Also, the amount of free proline at the end of dormancy and the stage of dormancy breaking was highest and the lowest was in the deep dormancy period.
Research Article
M. Tatari; M. Mahlouji; E. Ghorbani
Abstract
Introduction: The evaluation of storage characteristics and determination of resistance to post-harvest disorders in horticultural crops is highly important. ‘Viduja’ as new quince cultivar and KVD2 and KVD4 promising quince genotypes were collected from different regions of Isfahan Province. As ...
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Introduction: The evaluation of storage characteristics and determination of resistance to post-harvest disorders in horticultural crops is highly important. ‘Viduja’ as new quince cultivar and KVD2 and KVD4 promising quince genotypes were collected from different regions of Isfahan Province. As these cultivar and promising genotypes are new, it is necessary to determine the most appropriate harvest time for them based on effective harvest indices. This research was carried out for the determination of the best harvest time and storage period of these promising quince cultivar and genotypes.
Material and Methods: This experiment was carried out on 'Viduja' as new cultivar and KVD2 and KVD4 genotypes as promising genotypes and 'Isfahan' cultivar as control, which was grafted on hawthorn seedling rootstock. In April, the full bloom time of these cultivars and genotypes was monitored to report harvest time based on the number of days after flowering for each cultivar and genotype. Fruits were harvested on October 6th, 14th, and 21th, 2016 in the horticultural research station of Mobarakeh. Fruits were transferred to cold storage with 0±1°C and 90±5% R.H. for five months. Some traits were measured in the harvesting date and also at the end of every month. These traits included weight loss percentage, fruit firmness, TSS, TSS/TA, pectin, total phenol, surface browning and decay percentage. The experiment was carried out as a factorial experiment in a completely randomized design with three replicates (10 fruits in each replicate).
Results and Discussion: 'Viduja' cultivar and KVD2 and KVD4 genotypes were early flowering and had similar flowering time. Isfahan quince cultivar was late flowering and had moderate overlap with KVD2 and KVD4 genotypes. According to the results, the highest weight loss was observed in the fifth month of storage. In this month, 'Isfahan' and 'Viduja' cultivars showed the most and the least weight loss, respectively. Others showed increased water loss and reduced fruit weight with increased storage time. For example, with increasing the duration of storage in the cold storage, the weight loss of 'Gorton' quince cultivar increased. In all cultivars and genotypes, the highest TSS and TSS/TA were founded in the third harvest and fifth and fourth month of storage. Mosharraf and Ghasemi (34) reported that TSS in the last harvesting time and after five months of storage time was 20.16% in 'Isfahan' cultivar. In their research, TSS was 14.75% in harvesting time that was less than the rate of this trait in the current study. The highest TSS/TA belonged to 'Isfahan' and 'Viduja' cultivars. The highest fruit firmness was obtained at harvest time of 'Isfahan' and KVD2 genotype, and the lowest of that was observed in five months after the storage of KVD4 genotype. In the Esme quince cultivar, the fruit firmness in the third harvest quickly decreased, and after six months it was 3 kg cm-2. At harvesting time of KVD4 genotype, the highest phenol content was observed. 'Isfahan', 'Viduja' cultivars and KVD2 genotype showed the lowest phenol content after five months of storage. Increasing the storage period resulted in a decrease in phenol content in all cultivars and genotypes. Similarly, other researchers showed that the total phenol content gradually decreased with prolonged fruit storage (6 and 7). KVD4 genotype and 'Isfahan' cultivar showed the most pectin content at harvesting time. Increasing the storage time reduced the rates of pectin. According to Mosharraf and Ghasemi (39), increased storage period reduces pectin content in Isfahan cultivar fruits. The fruit surface browning was begun from the fourth month of storage, and there was no significant difference with the amount of this trait in the fifth month. Surface browning in the third harvest of Esme cultivar was also more than the previous harvestings, and eventually reached 70% (30). With prolonging storage time, the decay percentage increased. The first decay was observed from the third month of storage and reached its highest level in the fifth month. Isfahan cultivar had the highest percentage of decay. Other cultivar and genotypes had no significant difference in decay percentage.
Conclusions Finally, the best harvesting time for 'Isfahan', 'Viduja', KVD2 and KVD4 cultivars and genotypes were 185, 200, 200 and 193 days after full bloom respectively. Fruit storage in the cold for four months is advisable for 'Isfahan' and 'Viduja' cultivars and KVD4 genotype. In KVD2 genotype fruits, five-month storage is recommended.
Research Article
H. Mumivand; A.H. Rezaei Nejad; Sh. Taghipour; K. Sepahvand; B. Moradi
Abstract
Introduction: Drying is one of the most important post-harvest techniques for medicinal plants. Pelargonium graveolens (known as geranium) is an important, high-value perennial, aromatic shrub that can reach a height up to 1.3 m and a lateral growth of 1 m. The essential oil of P. graveolens is extensively ...
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Introduction: Drying is one of the most important post-harvest techniques for medicinal plants. Pelargonium graveolens (known as geranium) is an important, high-value perennial, aromatic shrub that can reach a height up to 1.3 m and a lateral growth of 1 m. The essential oil of P. graveolens is extensively used in the perfumery and cosmetic industries. Medicinal plants produce antioxidant compounds, which defend cells against degenerative effects of reactive oxygen species produced during oxidative stress and metabolism. Antioxidants are molecules that scavenge free radicals and reduce/prevent their damages. Therefore, the identification of natural antioxidants as preservative agents plays a pivotal role for the food, cosmetic and pharmaceutical industry. This study was conducted to investigate the effect of different drying methods (microwave-drying, oven drying and ambient-drying) on drying time and some phytochemical properties of P. graveolens.
Material and Methods: In order to evaluate the effect of different drying methods on drying time and some phytochemical properties of Pelargonium, an experiment was conducted at the faculty of agriculture of Lorestan University (Khorramabad, Iran) in 2017. The experiment was carried out based on completely randomized design with 12 treatments and three replications. The drying treatments were microwave-drying (300, 600 and 900 watts), oven-drying (45, 55 and 65 °C), ambient-drying (shade-drying at room, shade-drying in the field, sun-drying for five hours and then transfer to the room shade, sun-drying for 10 hours and then transfer to the room shade, and sun-drying) and fresh samples (as control). In all drying methods, the drying process continued until the moisture content of samples reached to 12% based on dry matter.
Results and Discussion: The results of analysis of variance showed the significant effect of drying methods on total phenol and flavonoids contents, antioxidant activity and essential oil content of the plants. The minimum and maximum of drying time (4.05 min and 6 days, respectively) was related to microwave-drying (900 watts) and shade-drying in the field, respectively. The highest total phenol (14.78 mg GA per 100 g dry matter) and flavonoid (12.83 mg quercetin per 100 g dry matter) contents were observed in plants dried at room shade and field shade, while the highest antioxidant capacity (IC50=1.02) was related to the fresh samples. The plants dried in the oven (45 °C) also had a notable phenol and flavonoid contents with high antioxidant activity. On the contrary, the samples dried in the microwave and sunshine showed the lowest amount of phenol and flavonoid contents and antioxidant activity. The highest essential oil content was obtained from oven-drying at 45 °C (0.2 %w/w based on dry mater), followed by shade-drying in the field (0.17 %w/w based on dry mater), and oven-drying at 55 °C (0.15 %w/w based on dry mater). While, the lowest essential oil content occurred with microwave-drying at 900 W (0.04 w/w based on dry mater). In this study, the amount of essential oil in the microwave-drying plants was significantly reduced by increasing the power of the microwave. The decrease in essential oil content with increasing oven temperature was also observed. The decrease in essential oil content with increasing oven temperature has also been reported in other species such as peppermint, dill, tarragon and sage and could be due to evaporation of the essential oil along with moisture losing during drying process. The results of Hamrouni Sellami et al. (2012) showed that drying in microwave at 800 w increased total phenol and flavonoid levels of sage (Salvia officinalis L.). Their results showed that as the microwave power increased from 600 to 800 watts, the total phenol content increased significantly. In research by Arslan et al., (2010), the lowest total phenol content was observed in the oven dried samples, whereas the highest total phenol content was obtained from the oven-microwave treatment and sun drying. The researchers explained that this increase was probably due to the release of phenolic compounds during drying and the reason for the decrease in phenolic compounds in the oven was attributed to the high temperature. Besbes et al., (2004) also reported that with increasing drying temperature, the amount of total phenolic compounds decreases, which may be due to the destructive effect of high temperatures on phenolic compounds. In general, it could be concluded that drying in high temperature of oven and high power of microwave reduces the amount of phenolic and flavonoid compounds, antioxidant activity and essential oil content of P. graveolens. While, shade-drying and oven-drying at 45 °C showed the least reduction in these traits compared to the fresh samples.
Conclusion: It can be concluded that shade-drying at room, shade-drying in the field and oven-drying at 45°C are more suitable for the P. graveolens .While drying treatments in the microwave and sunshine are not suitable for the species. In addition, the results showed that there was a significant relationship between total phenol content and antioxidant activity in both assays.
Research Article
A. Sharif; S.M. Kharrazi; S. Nejatizadeh; A. Khadem; M. Moradian
Abstract
Introduction: In traditional agriculture, a high concentration of nutrients is generally available to the plant, and a large amount of it will be leached out and is not available to the plant. But, if properly managed, the nutritional needs of the plant can be identified; it can increase the efficiency ...
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Introduction: In traditional agriculture, a high concentration of nutrients is generally available to the plant, and a large amount of it will be leached out and is not available to the plant. But, if properly managed, the nutritional needs of the plant can be identified; it can increase the efficiency of fertilizer use and also prevent the environmental pollution caused by excessive use of chemical fertilizers in the country. Therefore, the aim of this study was to increase the fertilizer utilization efficiency by choosing optimal fertilizer treatment and its optimum level for acclimation and optimum growth of gerbera tissue culture plantlets.
Material and methods: In the first experiment, different fertilizer treatments with different proportions of NPK were evaluated in a completely randomized design with 10 replications. In the second experiment, the different concentrations of the secondary group treatment (0.5x, 1x and 1.5x) were evaluated to determine the optimum level of fertilizer treatment. This experiment also was conducted in a completely randomized design with 15 replications. At the end of each experiment different parameters such as leaf number, petiole length, shoot dry and fresh weight, main root number, root length, secondary root number, root volume, root dry and fresh weight, chlorophyll a, b and total content were measured. Data preparation was done in Excel and data analysis was performed using the Jump 8 software. Mean comparison between treatments was performed with LSD test at 5% probability level and charts were drawn using Excel program.
Results and discussion: The results showed that the maximum root length, root volume, root dry and fresh weight and secondary root number was obtained from plantlets that was treated by the fertilizer treatment of the second group: K2SO4 (0.22 mM), KNO3 (3.62 mM), KH2PO4 (0.71 mM), NH4H2PO4 (0.35 mM), NH4NO3 (0.53 mM), Ca(NO3)2,4H2O (1.48 mM), MgSO4, 7H2O (0.4 mM), MnCl2, 4H2O (0.0049 mM), H3BO3 (0.020 mM), ZnSO4 (0.0061 mM), CuSO4, 5H2O (0.00048 mM), NaMoO4, 2H2O (0.00058 mM), FeSO4, 7H2O (0.0348 mM), Na2EDTA (0.0384 mM). So among the different fertilizer treatment, application of the fertilizer treatment of the second group was recommended. Calculation of nitrate and ammonium content used in six fertilizer treatments showed that the amount of ammonium used in fertilizer had a significant effect on root number and root dry weight. The maximum root number and root dry weight were observed in the second fertilizer group and then in the first fertilizer group. Urea was not used as a source of nitrogen in the fertilizer formula of these two treatments, while in other fertilizer treatments; urea fertilizer was used in addition to other sources of nitrogen supply. Since urea is converted into ammonium before its absorption by the plant, its application in the fertilizer formula has an effect on the amount of ammonium used in the fertilizer composition. It increases the ratio of ammonium to nitrate in fertilizer composition, which in turn influences root function. The ratio of potassium to phosphorus in the research of Khalaj et al. (4.40) is approximately as the same as the ratio of potassium to phosphorus used in the second group fertilizer treatment (4.50). The results of this ratio were also corresponded to Zheng et al. (4.6), Paradikovic et al (4.4), Hahn et al (4), Savvas and Gizas (4.8).The results of second experiment showed that plantlets grown under 1.5x concentration of second group fertilizer had better growth indices than two other treatments and had higher means in terms of root and shoot dry weight and petiole length. After counting the number of produced leaves at the end of the experiment, signs of leaf necrosis was observed under some treatments. Plantlets treated with 1 and 0.5 x concentrations of the second group treatment showed the highest incidence of leaf necrosis. Application of 1.5 x concentration of the second group treatment resulted in a 40% decrease in leaf necrosis symptoms compared to the other treatments. Also, the highest percentage of healthy leaves was obtained from 1.5 x concentration of the second group treatment, which showed a significant difference with the other treatments.
Conclusion: Generally, for the purpose of acclimation and optimal growth of gerbera tissue culture plantlets, fertilizer treatment of the second group {15(N), 10(P2O5), 30(K2O), 11.10(CaO), 2.10(MgO)} at a concentration of 1.5x is recommended.
Research Article
A. Rezaei; M.T. Ebadi; H. Pirani
Abstract
Introduction: Organic production is one of the important aspects in the medicinal plants industry and the use of organic fertilizers is very important in this topic. Seaweeds are important marine living resources with tremendous commercial applications and many commercial products from seaweed extract ...
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Introduction: Organic production is one of the important aspects in the medicinal plants industry and the use of organic fertilizers is very important in this topic. Seaweeds are important marine living resources with tremendous commercial applications and many commercial products from seaweed extract are used in agriculture and horticulture. Seaweed extracts can be used in liquid form as a foliar spray, soil drench or in powder and granular forms as soil conditioners and manure. Using seaweed extracts as fertilizers can improve plant productivity, because they contain growth-promoting hormones. Several studies have also shown that the seaweed extracts can suppress plant diseases and insect pests. Nowadays, seaweed extract is used as an organic fertilizer in order to increase the quantitative yield of medicinal plants and also resistance to environmental stresses. Summer savory is one of the medicinal and spice plants that has a high area under cultivation in our country for food and medicine. Various studies on its essential oil had been shown that it contains high amounts of phenolic compounds like Carvacrol, γ-Terpinene, Thymol, p-Cymene, β-Caryophyllene, Linalool, and other terpenoids.
Materials and Methods: In order to study the effect of different levels of seaweed fertilizer on the growth characteristics, plant material yield, essential oil percentage of summer savory, an experiment was conducted as a randomized complete block design with 3 replications at the Faculty of Agriculture, Tarbiat Modares University (TMU) during 2017. The treatments included: 0 (control), 2.5, 5 and 10 ml/liter seaweed fertilizer that they were used as a foliar application for three times in the growing season. According to the meteorological data, the area had an average rainfall of 246 mm and a semi-arid climate. In order to determine the physical and chemical properties of the soil, soil sampling and testing were done. To prepare the field, the soil tillage operation was carried out using a 40 cm depth plow. Then, plots with a 2 × 2 meters at a distance of half a meter from each other were prepared. The seeds used in this experiment were prepared from Varamin landrace, which is mainly cultivated by farmers in Tehran and Alborz provinces. Sowing operation was carried out manually. In each plot, 7 rows (30 cm spacing between rows) were cultivated and all of the plots were irrigated in the same conditions. The organic fertilizer (Bioalgax) used in this experiment was based on an extract of seaweed (Ascophyllum nodosum), which was obtained from the Kimitec company, Spain. This fertilizer is a natural source of phytohormones such as cytokinins, auxins, and gibberellins and also, it has some minerals. After reaching the height of 20 cm (eight weeks after planting), spraying of the fertilizer solutions was applied three times during the growing season at intervals of 10 days. The foliar application was carried out at sunset time by using a manual sprayer. The harvest was carried out at full flowering stage and 3 plants of each plot were harvested. The studied traits were: plant height, stem diameter, the number of branches, leaf length, and width, shoot fresh and dry weight, root fresh and dry weight, SPAD index, essential oil yield and content.
Results and Discussion: The results showed that different concentrations of seaweed fertilizer had a significant effect on the number of branches, shoot dry weight, root fresh and dry weight, leaf width and plant height at 1% probability level. They also had a significant effect on the shoot fresh weight, essential oil percentage, and yield at 5% probability level. On the basis of the results, the highest number of branches (35.44), leaf length and width (43.22 and 8.07 mm), stem diameter (5.00 mm), root fresh and dry weight (15.17 and 6.42 g), shoot fresh and dry weight (181.01 and 37.69 g) and SPAD index (48.13) were obtained from 10 ml/liter seaweed fertilizer and the lowest amounts were observed in control treatment. The maximum plant height (54.66 cm) and the highest percentages and the yield of essential oil (2.51% and 6.28 g/m2) were also obtained from 5 ml/liter seaweed fertilizer. According to the results, the response of summer savory to the use of seaweed fertilizer was positive and it could be placed in the fertilization program of farmers.
Research Article
M. Eisapoor; Kh. Hemmati; N. Hemmati
Abstract
Introduction: Horsemint (Mentha longifolia L.) is a valuable medicinal and aromatic plant belonging to Lamiaceae family. It was reported that the contents and composition of perceived pharmacological properties varied significantly among populations. The genus Mentha L. (Lamiaceae), is widely distributed ...
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Introduction: Horsemint (Mentha longifolia L.) is a valuable medicinal and aromatic plant belonging to Lamiaceae family. It was reported that the contents and composition of perceived pharmacological properties varied significantly among populations. The genus Mentha L. (Lamiaceae), is widely distributed in all continents (except in South America and Antarctica). The systematic of the genus is not very elucidated because of the strong morphologic variations, levels of ploidy (2n = 2x = 24 to 2n = 6x = 96), and hybridizations intra- and interspecific (or between spontaneous and cultivated forms). M. longifolia or horsemint is a fast-growing and perennial herb which cultivated in all regions. The species possesses antimicrobial and antioxidant properties. The antimicrobial properties of the essential oils can be attributed to the presence of pulegone, menthone and neomenthone because they can destroy the structure of different polysaccharides, fatty acids and phospholipids by altering the permeability of the cell membrane and destroying the bacterial wall. The essential oils of horsemint are said to be cyclohexane and aromatic, and pulegone is the main compound of these oils has a definite aroma in the range of intense to spicy mint. The effects of environmental conditions on the plant growth and development, reproduction and distribution are well known in plant ecology. Many studies have been carried out about the relationships among plant chemical contents, biological activity and environmental variables in the natural and cultivated plant species. This information has been used to determine the medicinal value and economic importance of plant products.
Materials and Methods: In this research, the effects of six habitats with different altitudes (habitats of Amol city) on some morphological and biochemical characteristics of horsemint plants were investigated in a completely randomized design with three replications. This study was done to compare the amount of pulegone, total phenol, total flavonoids, antioxidant activity, chlorophyll a, chlorophyll b, total chlorophyll, carotenoid and also morphological features of horsemint such as number of leaves per plant, number of branches per plant, number of flowers and number of nodes. For antioxidant properties using DPPH method in 517 nm wavelength, total amount of phenol using Folin-Ciocalteu method in 765 nm wavelength and the total amount of flavonoid were done using the aluminum chloride method in 415 nm wavelength and they were measured by spectrophotometer. Essential oil was extracted from dried aerial parts using distillation by Clevenger apparatus for 3 hours. Gas chromatography (GC) was used to measure pulegone.
Results and Discussion: The results showed that the altitude and ecotype significantly affecting the growth and biochemical characteristics of horsemint plant. The highest number of leaves (25) and the shoots (27) of horsemint were obtained in the Gat Lash region with 2000 meters and Siozmin with 1850 meters above sea level, respectively. Gat Lash and Siozmin had the highest and lowest content of photosynthetic pigments, respectively. Although there was no significant difference between the content of phenol and flavonoids in different habitats, the highest rates were observed in the Pardemeh and Gat Lash habitats. The results showed that the highest and lowest oil were obtained from ecotypes of Gat Lesh with 2000 meters and Vash Verin with 2300 meters above sea level, respectively. As the height increased, the amount of pulegone was also increased in the leaves, so that the highest amount of pulegone was found in Pardemeh )6069 ppm) habitat by 2600 meters above sea level.
Conclusions: Generally, for obtaining the highest essential oil content and pulegone, the best ecotypes were Gat Lash and Pardemeh habitats, respectively. Due to the importance and usage of secondary metabolites in the human life, investigating the relationship between environmental conditions with the production and accumulation of secondary metabolites in plants can be very useful. Our results showed that the climatic conditions had a significant effect on the morphological characteristics of the horsemint, thereby increasing or decreasing the essential oil. In the present study, the best habitat for the highest pulegone was Pardemeh habitat but the habitat of Gat Lash could be a suitable habitat for domestication and cultivation of this plant because of its higher essential oil yield and relatively good pulegone content. For this purpose, it is recommended to study different habitats of this species in other parts of the country for finding the best ecotypes.
Research Article
S. Hajizadeh; Z. Jabbarzade; M.H. Rasouli-Sadaghiani
Abstract
Introduction: Gerbera jamesonii is a permanent, herbaceous and chilling-sensitive plant species from the family Asteraceae that is native to hot regions. The species has high color diversity and it is among the top ten cut flowers in the world. Fulvic acids are a family of organic acids, natural compounds, ...
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Introduction: Gerbera jamesonii is a permanent, herbaceous and chilling-sensitive plant species from the family Asteraceae that is native to hot regions. The species has high color diversity and it is among the top ten cut flowers in the world. Fulvic acids are a family of organic acids, natural compounds, and components of the humus (which is a fraction of soil organic matter). They are similar to humic acids, with differences being the carbon and oxygen contents, acidity degree of polymerization, molecular weight and color. Fulvic acid remains in solution after removal of humic acid from humin by acidification. Fulvic acids are of relatively low molecular mass and less biologically active than humic acids. Among micronutrients, Iron (Fe) is a cofactor for approximately 140 enzymes that catalyze unique biochemical reactions and is an essential element for growth of plants. Lack of iron causes young leaves yellow and photosynthesis activity reduce significantly and consequently biomass reduce. Iron plays many essential roles in plant growth and development, including chlorophyll synthesis, thylakoid synthesis, chloroplast development, contribution in RNA synthesis and improvement the performance of photosystems. Nano-fertilizers can be substituted for conventional fertilizers. Studies showed that the effect of nano-particles on plants can be beneficial (seedling growth and development).
Materials and Methods: In order to investigate the effect of different concentrations of fulvic acid and iron nano chelate on flowering of gerbera as well as flower vase life of gerbera cv. Dune, an experiment was conducted as a factorial based on a completely randomized design with three replications during the years 2016-2017. The medium was included peat moss 65%, perlite 30% and cocopeat 5%. The seedlings of tissue cultured plants were planted into pots (size-20) (volume 7 L, height 19 cm, diameter 24 cm) in hydroponic greenhouse conditions. Day/night temperature regime was set at 20-25/13-16°C and light intensity at 400-500 μmol m-2 s-1. The plants were fed three times a week. The treatments were: fulvic acid at four concentrations of 0 , 50, 100 and 250 mg L-1 as drench and iron nano chelate at 4 concentrations of 0, 1, 2 and 4 gr L-1 as foliar application (15 days intervals for 4 months),. Two weeks after the last treatment, morphological parameters were measured. They were included flower fresh and dry weight, flowering stem length, flower longevity and vase life and the number of days to the appearance of flower buds. Also, the recorded physiological parameters included chlorophyll a, b and total chlorophyll, chlorophyll index and carotenoid.
Results and Discussion: The results of this study showed that, flower dry weight was increased with increasing the concentration of iron nano chelate. The highest flower dry weight )6.43g( was obtained from plants treated with 4 g L-1 iron nano chelate and the lowest one )5.57 g( from control plants, but flower fresh weight was not affected by these treatments. The highest length of flowering stem was observed in treatment of 2 g L-1 iron nano chelate. The lowest time to flowering was obtained from 50 mg L-1 fulvic acid without application of iron nano chelate. The results of means comparisons showed that fulvic acid and iron nano chelate caused to increase flower longevity significantly. The highest flower longevity (19 days) was obtained from 250 mg L-1 fulvic acid and 1 g L-1 iron nano chelate and the lowest mean (12.66 days) was related to control plants. Also, most of treatments caused to increase vase life compared to control. The highest vase life (14.66 days) was observed in 1 g L-1 iron nano chelate without fulvic acid while the lowest mean (6.66 days) was observed in control. Chlorophyll content (chlorophyll a, b and total chlorophyll) and carotenoid content of gerbera increased with increasing concentrations of fulvic acid and iron nano chelate in compared with the control.
Conclusion: According to the results obtained from this research, application of fulvic acid and iron nano chelate have a positive effect on most flowering and biochemical indices. Application of low concentrations of fulvic acid (50 mg L-1) supplemented with iron nano chelate caused to early flowering. Fulvic acid didn’t have any effect on flowering stem length and its application reduced the flower dry weight. While combined application of fulvic acid and iron nano chelate caused to increase flower longevity. Also iron nano chelate caused to increase flowering stem length, vase life and flower dry weight. In most of the biochemical indices, combined treatment of 100 mg L-1 of fulvic acid and 2g L-1 of iron nano chelate had better or favorable result on measured indices compared to the control treatment although the highest concentration of treatments did not have a negative effect and sometimes in some indicators also have more impact. Among these treatments, the concentrations of 100 and 250 mg L-1 fulvic acid and 2 and 4 g L-1 iron nano chelate can be effective for gerbera plant.
Research Article
S.F. Saberali; H. Nastari Nasrabadi; Z. Shirmohamadi Ali Akbar Khani
Abstract
Introduction: A rapid, complete, and uniform seed germination is important to establish a healthy seedling that is a critical key to successful crop production. Therefore, identification of effective factors on germination and plant response to various conditions are important to use an ...
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Introduction: A rapid, complete, and uniform seed germination is important to establish a healthy seedling that is a critical key to successful crop production. Therefore, identification of effective factors on germination and plant response to various conditions are important to use an appropriate agronomic managements. Temperature and water are the most important environmental factors controlling seed germination in plants. The crop growth models are among the most effective tools for using in crop management decisions. The response of seed germination to temperature and water potential can be simulated by thermal time, hydrotime and hydrothermal time models. Regarding the importance of watermelon production in Iran, this study was conducted to determine the cardinal temperatures of germination in watermelon plant, and also to quantify its germination in response to the temperature and water potential interaction. .
Materials and Methods: In order to investigate the effects of temperature and drought stress on seed germination and quantifying the germination responses; a factorial experiment was conducted with seven levels of temperature including 10, 15, 20, 25, 30, 35 and 40 °C and the six levels of water potential including 0, –0.25, –0.5, −0.75, –1.0, and –1.25 MPa, respectively. A Ψ of 0 MPa was obtained using distilled water. The negative Ψ levels were prepared by polyethylene glycol (PEG 6000; Merck, Germany) according to Michel and Kaufman (1973). For each treatment, four 25-seed replicates were placed in 9-cm petri dishes containing one disk of Whatman No. 1 filter paper, with 7 mL of test solutions. Cumulative germination percentage was transformed to probit regression against time log (Finney, 1971; Steinmaus et al., 2000), and the time taken for cumulative germination (tg) to reach subpopulation percentiles (10–90%) was estimated from this function according to Steinmaus et al. (2000). Then the germination rates (GR) were calculated as the inverses of the germination times for each percentile at each T or Ψ. The preliminary estimation of the parameters in the TT, and HT models were obtained by plotting GR versus T and Ψ for each percentile. Then using repeated probit analysis developed by Ellis et al. (1986), the exact parameters for the TT, HT and HTT models were determined for the whole seed population. All statistical procedure were done by SAS and Excel software, and the figures were drawn by SigmaPlot10 software.
Result and Discussion: The analysis of variance showed that the temperature, water potential and their interaction had significant effect on the germination percentage of the watermelon plant. Seed germination of watermelon was about 96 % under the optimal conditions. However, the germination ability was affected by the temperature and water potential of the seedbed. The results showed that the germination was decreased by decreasing water potential, at all temperature levels. The seeds of watermelon germinated over a range of water potentials from 0 to -1 MPa. Furthermore, the lowest germination loss associated with decreasing water potential observed at temperature range of 20-30 °C (compared to temperatures below and above this range). The maximum percentage of germination was recorded at 20-30 °C, while no seeds germinated at 10 and 40 ° C. The results also showed that the highest germination rate was obtained at 25 °C and the germination rate decreased at lower and higher temperature than this range. While watermelon seeds were grown under no water stress condition, the estimated base and ceiling temperatures of germination by a linear regression method were 10.7 and 40.0 °C, respectively. However thermal time model was used, but the base and the maximum temperatures were estimated as 11.5 and 40.1 °C, respectively. Furthermore, an optimum temperature of 25.2 °C was predicted by hydrothermal time model for watermelon germination. The results showed that the base temperature and median thermal time to germination were varied with changing water potential. The hydrotime analysis showed that the base water potentials was in a range from -0.45 to -1.23 Mpa, that differed with changing water potential. Watermelon seeds had higher base water potential and also required a longer hydrotime for germination under non-optimal temperature. Hydrothermal time analysis showed that seed germination responses to temperature and water potential might as well quantified by parameters derived from hydrothermal time models (R2= 0.90-0.92). The amount of hydrothermal time required to germinate was 40.5 MPa °C days on the suboptimal and supra optimal temperature ranges. The HTT model showed that the Ψb(50) increased by 0.09 MPa with every degree increase in temperature above optimum temperature.
Conclusions: The thermal time, hydrotime and hydrothermal time models well described germination time course of watermelon seeds in response to temperature and water potential.Thus, the estimated parameters of these germination models allowed us to characterize the germination behavior of watermelon seeds under varying environmental conditions and global warming.
Research Article
Y. Selahvarzi; M. Kamali; J. Nabati; H. Ahmadpour Mir
Abstract
Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to ...
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Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to their cells, tissues, and organs. Research has shown that by altering membrane properties during cold stress, metabolic balance is disturbed and with the increase in toxic metabolites, secondary damage to the plant can occur. At low temperature, decreases the efficiency of energy transfer to the center of the photosystem II. In addition, low temperatures are the main cause of the formation of reactive oxygen radicals. Also, lowering the temperature in the presence of light, due to the imbalance between light absorption and photosynthesis, increases the risk of light oxidation. Low temperature also reduces the activity of Rubisco. The amount of free proline in many plants increases significantly in response to environmental stresses such as frost stress, and stabilizes the membrane during cold stress.On the other hand, the use of some organic materials such as organic mulches increase temperature of the soil, and thus helps plant from frostbite. Use of organic mulch is widespread in agriculture due to the positive effect in soil temperature, weed control and moisture retention. Also, these mulches are effective in height, growth and flowering, early maturity and total yield of the products. Mulches in the warm seasons reduces soil temperature. Use of mulch can also help plants to withstand frostbite. Organic mulch decomposition in appropriate temperature and humidity conditions, liberates the nutrients gradually and provides for root plant and microorganisms of the soil. Organic mulches can reduce the effect of salt toxicity on plant growth and actively increase soil desalination. The most important benefit of mulch is the increase in soil temperature in the seed area, which accelerates the growth and yield of the product. Use of straw as mulch resulted in accelerated germination in cucumber. Use of straw mulch leads to an increase in temperature at night, thus protecting plants from temperature stress that has a positive effect on the growth and development of wheat.
Material and methods: In order to investigate the effect of freezing stress and using different types of organic mulch for Aquilegia plant, this experiment was conducted as a factorial experiment based on completely randomized design with four replications at Faculty of Agriculture, Ferdowsi University of Mashhad. The experimental treatments included four types of mulch (control (without mulch), 50% soil + 50% manure, 50% soil + 50% leaf needle + 50% soil + 50% rice bran) and five levels of freezing temperature (0, -5, -10, -15 and 20). Characteristics such as percentage of electrolyte leakage, relative water content, chlorophyll index and total chlorophyll, leaves number, leaf area, plant dry weight and proline leaf content were considered.
Results and Discussion: The results showed with decrease of temperature from 0 to -20 °C, stem diameter, leaf area and leaf number in bran mulch treatment decreased by 42.6%, 73.4%, 21.2% respectively, also stem diameter, leaf area and leaf number in mulch of leaf needle were 35.2%, 9/64%, 47.6%, in manure mulch were 20.20%, 46.4%, 7.8% and in the control of mulch decreased, 32.8%, 79.7%, 30.7%, respectively. At -5 °C, the amount of proline was 26% in the leaf and at -20°C, the amount of proline increased 50% compared to the control. Also, the lowest proline (0.73 μmol / g fresh weight) was obtained from the plants that treated with bran mulch. With application of, electrolyte leakage reached 63.6%, 68%, 61% and 57% in control conditions bran, needle and manure, respectively. In short, the least electrolyte leakage was observed in manure. On the other hand, when temperature dropped from 0 to -20 °C, the percentage of electrolyte leakage increased in Aquilegia. Relative water content of the leaf were 24% at 0°C, 38% at -15 °C and 23% at -20 °C. In terms of non-use of mulch, the relative water content was 36% and reached a 42% and 40% with application of manure and needle using mulch. By measuring the total carbohydrate found in Aquilegia leaf, it was observed that the amount of this trait was increased under frost stress. In general, although frost stress reduced the morphological traits of Aquilegia, use of organic mulch resulted in the improvement of these traits. The best results were observed in manure mulch.
Research Article
A. Ajili Lahiji; A. Mohammadi Torkashvand; A. Mehnatkesh; M.N. Navidi
Abstract
Introduction In order to land classification for agricultural and natural resources, the most important criterion and factor is the production or yield of the lands. The best way to evaluate a method is to interact between the yield and potential of the product with the land specification involved in ...
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Introduction In order to land classification for agricultural and natural resources, the most important criterion and factor is the production or yield of the lands. The best way to evaluate a method is to interact between the yield and potential of the product with the land specification involved in the production. One of the new methods in the land evaluation for different uses is the modeling or simulation of the intended use. Artificial neural networks are one of the new tools that are used today to simulate yield and determine the effective factors in the production of agricultural crops. New land evaluation methods include different modeling techniques, which these new methods, including simulations, are used in land valuation methods to test the ability of models for determining the relationship mentioned. An artificial neural network is one of the techniques that can do nonlinear analysis. It is important to recognize the most important input parameters to the predictive models of olive yield, which are also considered to be effective variables in production. Through the process of sensitivity analysis, valuable information about the sensitivity of the model to its input variables can be provided to the designer and model architect. In north of Iran, in the southern areas of Gilan Province, the most important olive gardens of the country are located in the southern part of the country. Different soil and water, topographical and climatic factors affect the yield of olive orchards.
Materials and Methods Climatic data, soil and water characteristics, topographic characteristics and leaf nutrition elements as input variables and olive yield were used as output models. Twenty-eight factors were selected as the most important factors or variables affecting the yield of olive orchards. These input variables included soil properties: EC, (TNV), organic carbon percentage, available phosphorus, available potassium, clay percentage and silt percentage; irrigation water characteristics including: EC and content of irrigation water; topographic characteristics including: altitude and the slope; the concentration of nutrients in leaves included: nitrogen, phosphorus, potassium, iron and zinc; climatic factors including: sunny hours, evaporation rate, average temperature and olive yield were considered as output of artificial neural network model.
Results and Discussion Using the MATLAB software by artificial neural network, the best structure of this network was obtained for the component of the yield of olive. The trained structure had 28 input nodes in 5 groups and one output node. The number of hidden nodes, 38 nodes and the most appropriate number of repetitive learning based on the test and error, 20 were determined for olive product yield. After determining the best structure of the neural network with a R-test of 80%, using Hill's sensitivity analysis, the model's response to each of the input variables was studied and the most important factors influencing the yield of olive oil were obtained. Based on the results of sensitivity analysis, the most important parameters affecting the yield of olive are content of leaf nitrogen, soil phosphorus, winter evaporation, summer evaporation, average autumn temperature, summer sunshine, leaf potassium, salinity, salinity, and slope, respectively. In general, this study showed that the amount of nitrogen and phosphorous is the most important factor for the production of olives, and then variables that are related to the amount of water in the soil, (summer evaporation, average autumn temperature, summer sunshine), were identified as important. The concentration of potassium, iron and zinc in the leaf as a nutrient element and water and soil salinity from stressors for plants and slope are important topographical factors that affected the amount of soil depth and soil water content as the most important factors in olive crop production.
Conclusion In brief, the role of micro and macro nutrients and the factors affecting the maintenance of water in the soil and providing moisture for the plant. In addition to nutrients, gardeners should consider soil and water salinity, which is a stressor for plants, as well as slope, which is important topography factor that effective on soil depth and water available and nutrients for plants as the most important factors in olive production.
Research Article
F. Rasouli; M. Gholipoor; K. Jahanbin; H.R. Asghari
Abstract
Introduction: Salicylic acid and jasmonates (chemical elicitors) are considered as key signaling compounds in induction process, which leads to accumulate of secondary metabolites. External uses of these compounds cause to induce pseudo stress in plants and excites defensive replies in plants, in response ...
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Introduction: Salicylic acid and jasmonates (chemical elicitors) are considered as key signaling compounds in induction process, which leads to accumulate of secondary metabolites. External uses of these compounds cause to induce pseudo stress in plants and excites defensive replies in plants, in response to induction of oxidative stress, the plant increases amount of antioxidant genes expression and increase enzymatic activity and non-enzymatic antioxidants concentration (they often have a medicinal aspect).
Material and methods: The present study investigated the effects of jasmonic acid and salicylic acid on hydrogen peroxide content, electrical lockage, GPX, GST and PAL activity, total phenol, flavonoid and anthocyanin changing in Stevia rebaudiana bertoni under field conditions. The experiment arranged as a randomized complete block design with 12 treatments and three replications in 2015-2016 at Amol city in Mazandaran Province in Iran. Experimental treatments were spraying by different concentration of jasmonic acid, salicylic acid and components of jasmonic acid- salicylic acid. Foliar application started after plant establishment in vegetative phase. Each experimental plot was 2 m× 3 m consisting 10 rows with 30 cm row spaces and seedling transplanted on 15 May. At the end of foliar application, sampling was done for the measuring. Sampling for biochemical analyses from second fully developed leaf was done and freezed in liquid nitrogen, then quickly carried out to laboratory.
Results and Discussion: The analysis of variance showed that different concentration of jasmonic acid and salicylic acid and spraying both of them in 7-day intervals appeared to be effective (with 99% confidence) on studied traits (data not shown). Spraying with jasmonic and salicylic acid increased hydrogen peroxide content in 9 treatments compared to the control. The highest amount of hydrogen peroxide content in compounds treatment 20 ????M JA -1 mM SA with mean of 5.46 ????mol in fresh weight observed. Plant in response to jasmonic and salicylic acid spraying increased GPX activity in 10 treatments and GST activity in 7 treatments compared to the control and follow them electrical lockage in most treatments (10) was lower than control. The highest amount of GPX activity in treatments 5 ????MJA and 5 ????MJA with average of 0.11 ????molmin-1g-1 FW observed. The highest amount of GST activity was obtained from treatments of 0.5 mM SA -5 ????M JA and 1 mM SA with average of 0.35 ????molmin-1g-1 FW. The PAL enzyme activity (the first enzyme in phenyl proponed compounds biosynthesis pathway) in 10 treatment increased. The highest amount of PAL activity was in compounds treatment of 50 ????M JA -1 mM SA with average of 1140 ????mol cynamic acid mg-1 protein min-1. The PAL enzyme activity had correlation with hydrogen peroxide concentration and GST activity. The PAL enzyme initiates a phenylpropanoid route that converts L-phenylalanine to trans-cyanamide acid deamination. The PAL enzyme can consider as an antioxidant enzyme because it has the role of depositing oxygen radicals through phenolic compounds. Spraying increased total phenol content in 8 treatments compared to the control. The highest amount of total phenol content was observed in compounds treatment of 20 ????M JA -1 mM SA with mean of 423.7 mgg-1 FW. Spraying with jasmonic acid and salicylic acid increased flavonoid concentration in 9 treatments compared to the control. The highest amount of flavonoid content was in treatment of 20 ????M JA -1 mM SA with mean of 110 mgg-1 FW. Spraying increased anthocyanin concentration in 6 treatments compared to the control. Anthocyanins are the most important group of natural pigments after chlorophyll that are involved in light protection. The noticeable point is that in most treatment PAL enzyme activity, total phenol, flavonoid and anthocyanin content in compound treatment increased.
Conclusion: The highest amount of total phenol and flavonoid content observed in compounds treatment of 20 ????M JA -1 mM SA and anthocyanin increased in total compounds treatment and using PAL enzyme activity had correlation and significant effect (data not shown). Stevia has anti–cancer effect, anti-blood glucose effect and anti-cardiovascular effect. This effects for the existence phenolic compounds in stevia such that had the ability to remove ROS, so increasing phenolic component by jasmonic acid and salicylic acid spraying in stevia was useful.
Research Article
A. Ramezan Ghanbari; I. Rohollahi
Abstract
Introduction: The genus Muscari has 47 species according to the World Checklist of Selected Plant Families. M. armeniacum, belonging to the family Asparagaceae, is cultivated in pots and gardens in the temperate regions. Muscari armeniacum is commonly known as grape hyacinth owing to its clusters of ...
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Introduction: The genus Muscari has 47 species according to the World Checklist of Selected Plant Families. M. armeniacum, belonging to the family Asparagaceae, is cultivated in pots and gardens in the temperate regions. Muscari armeniacum is commonly known as grape hyacinth owing to its clusters of small, bell-shaped, cobalt-blue flowers that look like clusters of upside-down grapes. Traditional methods of propagation of Muscari species are rather slow, since the bulblet production from the mother bulbs is extremely low. Muscari as a cold resistance, bulbous flower with blue color and tendency to flowering many times can be used in many prospects. On the other hand, the color of M. neglectum is precious as natural pigment, and it has many beneficial and useful compounds that may support human health. Traditionally, scoring facilitated the in vitro and ex-situ propagation of bulbous flower. The manipulation of ploidy is a valuable tool in improving crops. Out of many applicable methods, the use of chemicals to induce changes in chromosome number has been well established. Colchicine has been successfully applied to induce polyploidy in a series of crop species. The chromosome reduplication of Muscari armeniacum can be induced with mixed and soaked colchicine.
Material and Methods: Mature bulbs of Muscari armeniacum were bought online (www.flowerbulbsholland.com). After treatments in first and second experiment, bulbs were cultivated in experiment garden. Polyploidy induction and viability percentage by colchicine and scoring in Muscari were evaluated separately in tow factorial experiment based on the completely randomized design with three replications for two years. In the first experiment colchicine, 0.05% by 12, 24 and 32 hours of soaking time under scoring (with scoring and without scoring) treatment were evaluated. Finally, morphological traits such as raceme length, leaf length, leaf number, leaf width, and peduncle length were evaluated and in second year morphological traits, as well as microscopic traits including stomata numbers, stomata densities, stomata length and width were evaluated. In the second experiment, colchicine 0.05 and 0.1% with 24 h soaking time and scoring (with scoring and without scoring) treatment in three replications were examined according to the first experiment details. Five well expanded leaves of each plant were selected to measurement and scoring the size and density of stomata. Three samples of epidermal cells were obtained from lower surface by nail varnish technique. A small area of abaxial side of leaves was covered with thin layer of clear nail polish and left to dry. After drying the polish, it was removed with a tip forceps then placed on a glass slide and observed through the light microscope at 400 x magnification and studided bu=y digital image processing and analysis. Stomatal density, length and width were measured for each image. Stomatal elongation was counted as the ratio of stomatal length and stomatal width.
Results and Discussion: Results of the first experiment showed the heights viability (100%) and flowering (55%) in non-scoring bulbs and 12 hours colchicine treatments. Also the lowest viability (55%) and flowering displayed in 32 hours colchicine and scoring treatments. At the second year of first experiment the highest viability percentage (75%) and flowering (10%) indicated in non-scoring bulbs and 32 hours colchicine treatment. The lowest viability (30%) and flowering (0%) percentage showed in 12 hours colchicine treatment with scoring bulbs. At the second year of first experiment 12 hours colchicine 0.05% significantly increased leaf width (0.63) and stomata width (0.015). Based on our results in the first experiment, in second experiment only 24 hours colchicine 0.1% treatment was evaluated. At the second year of second experiment colchicine and scoring interaction treatments had significant effects on stomata numbers. Bulbs that were scored and treated with colchicine 0.1% didn’t germinate and colchicine 0.05% decreased stomata density significantly compared to control.
Conclusions: The results of the experiment showed that colchicine 0.05% in 12 h of soaking time is one of the best treatment for Muscari polyploidy induction. Whereas, 32 h colchicine 0.05% treatment showed the highest flower percentage and viability in second year. Also, scoring and colchicine 0.1% had a negative effect on the viability and the flowering percentage. High colchicine concentration and scoring treatment decrease viability and flowering. Finally, colchicine 0.05% for 24 h without scoring could increase the possibility to induce ploidy.
