Medicinal Plants
Z. Safaei; M. Azizi; Gh. Davarinejad; H. Arouiee
Abstract
IntroductionThe ever-increasing tendency to the use of medicinal plants in the world has grown concerns about their cultivation and production processes. As medicinal plants are more compatible with the nature, special interest and attention has recently been given to herb therapy, and use of medicinal ...
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IntroductionThe ever-increasing tendency to the use of medicinal plants in the world has grown concerns about their cultivation and production processes. As medicinal plants are more compatible with the nature, special interest and attention has recently been given to herb therapy, and use of medicinal plants, being limited by the rise of pharmaceutical drugs, has become again common and widespread due to a number of reasons. Nigella sativa L. is one of the herbs that has a variety of uses and has been being used in iran’s traditional medicine since old times. Today this plant is considered as one of the most important kinds of medicine. Therefore, it is of great importance to conduct some researches on the herbs around the country due to different ecological requirements. N. sativa belonging to buttercup family, with the scientific name of Ranunculaceae, is an annual, dicotyledonous, herbaceous plant. In several studies, N. sativa has been reported to have anti-oxidative, anti-inflammatory, strengthening of immune system, and anti-histamine and oil extract properties. Furthermore, several effects such as lowering blood sugar, lipids, and hypertension, excretion of bile and uric acid, protection of liver, kidney and cardiovascular tissues as well as anti-seizure, anti-cancer, anti-microbial and anti-parasitic effects related to this plant have been reported. The aim of the present study is to improve the yield and yield components and oil of medicinal plant N. sativa by anti-transpiration compounds under drought stress conditions. Materials and MethodsAn experiment was conducted at Research Station,Faculty of Agriculture, Ferdowsi University of Mashhad, in 2012-2013. The research was performed using a split plot experiment based on a randomized complete block design with three replications. The irrigation intervals (8 and 16 days) in main plots and anti-transpiration compounds of chitosan (0.25, 0.5 and 1%), Plantogopsyllium mucilage (0.5, 1 and 1.5%) and arabic gum (0.25, 0.5 and 0.75 %) were put in subplots with three replications. Also, the distance between the main plots in each block and distance between the two blocks were assigned as 100 cm and 200 cm, respectively; so that the moisture content of a plot had no effect on the adjacent plots. Planting date was April16 and planting was performed by hand in 0.5cm-deep furrows. Throughout the growing season, anti-transpiration compounds were applied concurrently with the imposition of drought stress, administered weekly at sunset until the flowering stage. Subsequently, yield, yield components, and oil content were measured. Results and Discussion Results showed that irrigation intervals had significant effects on all studied characteristics with the exception of 1000 seed weight. ncreasing irrigation intervals reduced percentage yield and yield components and oil of black cumin grains. Anti-transpirants compounds did have significant effects on percentage of oil and yield and yield components of black cumin grains. There were significant difference between different anti-transpirants compounds in terms of oil and yield components yield and of black cumin grains. The 8 days irrigation interval produced more grain yield compared with 16 days irrigation intervals (621.56 vs. 484.23 kg/ha). The highest oil (27.74%) and lowest (21.74%), respectively, at treatment anti-transpirants compound chitosan1 percent With 8 days irrigation interval and gam arabic 0.25 percent was obtained with 16 days irrigation interval and chitosan stimulating abscisic acid synthesis in the treated plant would result in stomatal closure, reduction of stomatal conductance, transpiration rate and water content. They also pointed out that the anti-transpiration effect of chitosan was because of its stimulatory effect in increasing abscisic acid concentration in the treated leaves of bean plant. As the above compounds are natural and biodegradable, as well as safer and less expensive than other chemical anti-transpiration compounds, they can serve as a good alternative to the chemical compounds. Cognition and expertise in water relations of plant and drought stress tolerance is considered as the main program in agriculture and the ability to withstand this stress is of great economic importance. Conclusion The anti-transpiration compounds led to significant changes in terms of all the studied traits compared to the control, indicating the effectiveness of theses natural compounds. Providing the appropriate conditions, 1% chitosan treatment can enhance the yield under drought stress. Spraying by arabic gum did not improve the growth conditions. According to this experiment, 1% chitosan treatment and 1.5% Plantago psyllium mucilage is considered the most appropriate strategy to enhance the yield of Nigella sativa under drought stress.
Growing vegetables
R. Azarmi; Y. Hosseini
Abstract
Introduction
Cucumber is one of the important greenhouse vegetables in Iran and the world. This product, in Iran, has the largest area under cultivation in comparison with other greenhouse vegetables, and according to the statistic in 2020, the Office of herbs, vegetables and ornamental plants ...
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Introduction
Cucumber is one of the important greenhouse vegetables in Iran and the world. This product, in Iran, has the largest area under cultivation in comparison with other greenhouse vegetables, and according to the statistic in 2020, the Office of herbs, vegetables and ornamental plants Ministry of Agriculture, the greenhouse cucumbers area under cultivation in Iran is 15000 ha. Cucumber is the product of warm and temperate season (with mild winters) and is very sensitive to adverse environmental conditions and even rare changes in soil moisture content will have a significant adverse effect on its growth and yield. Cucumber root is shallow, it is fibrous, and its shallow root causes its sensitivity to drought so that its main root penetrates 5–10 cm in heavy soil and 20-30 cm in light soils. This plant has an extensive and almost thin root system that has the possibility of expansion in a wide range horizontally, and, therefore, it can produce mass root, at the depth of 30 cm. In order to study the effect of grafting and water stress on morphological characteristics greenhouse cucumber (Cucumis sativus L), an experiment was conducted as complete randomized block design with three replications.
Materials and Methods
This research has been carried out in the city of Pars-Abad, Ardabil province, Iran. The longitude of Pars-Abad is 47°55ʹ E, latitude is 39°38ʹ N, and its height distance sea level is 32 meters. This research was done in the greenhouse of the Moghan Agriculture and Natural Resources Faculty in a complete randomized block arranged in split plot with three replications. To determine the characteristic curve of soil moisture, soil samples was selected and the weight moisture percentage at pressures of -0.3, -5, -10 and -15 bar, which include the important potential of the soil, was determined by using Pressure plate’s apparatus and soil moisture characteristic curve was mapped and soil parameters characteristic curve was determined. this study, the main factor included water stress in three levels of 90, 60 and 40% field capacity and the secondary factor included three rootstocks of Shintoza cucurbits (Cucurbita moschata × Cucurbita maxima), Flexi Fort cucurbits (Cucurbita moschata × Cucurbita maxima, cucumber varieties Nagen 972 (Cucumis sativus L.) self-grafted and check (ungrafted) cucumber varieties Nagen was studied as a scion. In this study, the grafting method of hole insertion was used as the best grafting method for Cucurbitaceous.
Results and Discussion
Duncan test results showed that with increasing stress, the diameter of the main root, at the rootstocks of Shintoza and Flexi Fort, increased almost twice as much as the control. The results showed an approximately 3 times increase in the yield, at the rootstocks of cucurbits at different levels of stress and it had a significant positive relationship at 1% level with the length, diameter and weight of root. The highest yield related to the Flexi Fort rootstocks was obtained 2.99 kg per plant in the water stress condition 90% of field capacity and then Shintoza rootstocks ranked second with 2.617 kg per plant, at 60% water stress. The maximum water use efficiency related to Shintoza rootstocks was at 32% and Flexi Fort rootstocks, Nagen and control, were respectively 30, 22 and 36% of Potential evapotranspiration.
Conclusion
The results showed that, with increasing water stress, unlike the control, which was associated with decreasing linear trend of yield, Treatments with cucurbits grafting at Shintoza and Flexi Fort rootstock, faced with increased water stress, from 40 % to 90 % of field capacity by minor reducing of product. This can be due to increasing root uptake parameters such as length, weight and length of the main root in these Treatments. Correlation analysis showed a significant relationship at **P<0.01 level between a percentage of roots and yield. The results in all applied water stress also showed a high yield of grafted treatments about three times more than the control. Reducing the yield sensitivity factor in cucurbits Treatments, causes the plant could maintain its performance in irregular watering that encounter the plant with tension. The high water use efficiency in cucurbits Treatments shows that it is possible to perform economic optimization in the production based on water consumption scarcity of water.
Pomology
R. Fifaei; H. Taheri; Y. Tajvar; E. Gholamian
Abstract
Background and Objectives
Water is a main factor in agriculture activities and almost 70 percent of world water resources are consumed in agriculture. Drought consist the most important environmental restriction to plant growth and production. Drought stress is known to change a range of physiological ...
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Background and Objectives
Water is a main factor in agriculture activities and almost 70 percent of world water resources are consumed in agriculture. Drought consist the most important environmental restriction to plant growth and production. Drought stress is known to change a range of physiological processes such as photosynthesis, stomatal conductance and transpiration rate. Citrus are one of sub-tropical and tropical fruits and the most important horticultural products in the world that tolerate low temperature and weak drainage but as regards Citrus growing in sub-tropical and tropical regions that often expose drought. Drought is one the environment stress factors that is caused changes in plants morphological and physiological characteristics. Study of survival time in the three citrus rootstocks in sever stress circumstances showed that this time in rootstocks poncirus, cleopatra mandarine and former-alkaeid 5 were 11, 13 , 20 days, respectively while survival time in valencia on the rootstocks was 21, 26 and 29 days, respectively. This study was performed in order to study drought tolerant in natural genotypes with the poncirus and rough lemon. And so, morphological and physiological characteristics were investigated in this genotypes.
Materials and Methods
This research was performed in separately two tests in Citrus and subtropical fruits research center on 2016. In the first test, survival time and total transpiration and in the second test, organs fresh and dry weight, ion leackage and leaf relative water content were assessed in factorial experiment based on randomized completely design in nucellar seedlings of 8 Citrus natural genotypes (G10, G11, G12, G16, G18, G22, G23, G25) poncirus and rough lemon under glasshouse conditions (with temperature 26-28 degree centigrade in day and 20-22 degree centigrade in night and 80-85 percent relative humidity). Factors were 10 Citrus genotypes and two treatment of irrigation (optimum irrigation and withholding irrigation for six weeks) in the second test and 10 Citrus genotypes in the first test. In this study, medium weight moisture is calculated and due to the soil moisture characteristics curve was obtained medium matric potential. The matric potential rate was in control -0.03 megapascal and in sever stresss -1.5 megapascal. Organs fresh and dry weight were measured on digital balance with accuracy 0.01 gr. (model GM 6101, Germany). S amples were dried in oven (70 degree centigrade and for 48 hours). RWC is measured by using of fresh weight, dry weight and turgid weight in this formula: RWC= [(FW-DW) / (TW-DW)] × 100. Ion leackage was determined by use of 4 equal leaf segments and measuring of primary and secondary ion leackage in this fomula: EL (%) = (EL1/EL2) × 100. The first research was included of 10 treatment, six replication and one seedling in every plot and the second research was included of 20 treatment, three replication and two seedlings in every plot. SAS software (ver. 9.1) and Duncan test were used to variance analysis and mean comparison. Excel software was used to graphs drawing.
Results
The results showed that in first test, poncirus (with 125 days) and G11 (with 78 days) have longer survival time and are more tolerant and so rough lemon (with 38 days) and G12 (with 44 days) were more susceptible. Others were intermediate. Slowest of water consumption time in poncirus and the most quick in rough lemon, and so maximum of total transpiration in G25 and minimum in poncirus was observed. In second test, decrease maximum of leaf, shoot and total fresh weight in G22 (arranged by 0.37, 0.47 and 0.42) and decrease minimum in G11 (arranged by 0.48, 0.54 and 0.52), decrease maximum of root fresh weight in G22 (with 0.35 fold) and decrease minimum in G18 (with 0.52 fold), decrease maximum of root/shoot fresh weight in G18 (with 0.61 fold) and decrease minimum in G23 (with 0.65 fold) and increase maximum of root/shoot dry weight in G16 (with 1.56 fold) and increase minimum in poncirus (with 1.3 fold) was observed in compared with control. In stress, G18 (with 32.32 percent) and G12 (with 34.37 percent) had leaf relative water content minimum in compared with control. G12 (with 78.59 percent) and G18 (with 73.16 percent) had maximum and poncirus (with 31.85 percent) minimum ion leackage percent in compared with control. Therefore, rough lemon, G12 and G18 as susceptible and poncirus and G11 as tolerant to drought were introduced.
Discussion
In stress conditions, poncirus has longer survival time, slower water consumption time, minimum total transpiration and minimum ion leackage percent and is most tolerant. Rough lemon has shower survival time, more rapid water consumption time and is most susceptible. Other genotypes locate in after grades. Therefore poncirus and rough lemon can be used as rulers in tests of drought study.
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.
M. Abaspour Esfaden; S. Kallaterjari; F. Fatehi
Abstract
Introduction: Catharanthus roseus is a beautiful herbaceous plant, belonging to Apocynaceae family, which is widely cultivated due to its unique and beautiful appearance. It is native to the Caribbean Basin and has historically been used to treat a wide assortment of diseases. European herbalists used ...
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Introduction: Catharanthus roseus is a beautiful herbaceous plant, belonging to Apocynaceae family, which is widely cultivated due to its unique and beautiful appearance. It is native to the Caribbean Basin and has historically been used to treat a wide assortment of diseases. European herbalists used this plant for different conditions such as headache and a folk remedy for diabetes. The effects of drought range from morphological to molecular levels and are evident at all phonological stages of plant growth at whatever stage the water deficit takes place.The limitation of water resources in our country is one of the important issues in landscape. However, we can alleviate the adverse effects of water stress with the use of some biological and non-biological stimulators. Under severe stress conditions, the antioxidant capacity may not be sufficient to minimize the harmful effects of oxidative damage. Therefore, synthesis of signal molecules in plants is an important step in our better understanding of how plants respond to environmental stresses. Several such signal molecules have been identified in plants such as jasmonic acid, ethylene and salicylic acid (SA). SA is considered as a hormone-like substance, which plays an important role in regulating a number of plants’ physiological processes including photosynthesis. Besides, L-arginine is an amino acid, which can alleviate the adverse effect of drought. Among the 21 proteinogenic amino acids, arginine has the highest nitrogen to carbon ratio, which makes it especially suitable as a storage form of organic nitrogen. Synthesis in chloroplasts via ornithine is apparently the only operational pathway to provide arginine in plants. Therefore, the present study was conducted to evaluate the effect of salicylic acid (SA) and L-arginine on morpho-physiological properties of C. roseus.
Materials and Methods: This experiment was carried out as a factorial with two factors including the foliar application at five levels (control, L-arginine 1.5 and 3 mM, SA 100 and 200 mg /L) and water stress at three levels (100, 70 and 40% field capacity (FC)) in a completely randomized design with three replications. Water use efficiency (WUE), the root/shoot weight, flower number, flower diameter, leaf chlorophyll content, peroxidase and superoxide dismutase activity of leaf, and leaf macronutrients (nitrogen, phosphorus and potassium) were measured.
Results and Discussion: The results showed that WUE in plants under moderate stress (70% FC) was higher than the plants in control and severe drought condition (40% FC). Root/shoot weight at no foliar application (control) × 40% FC and L-arginine 1.5 mM × 40% FC was higher than other treatments. The number of flowers in the treatments of 100% FC and 70% FC was more than 40% FC. The highest flower diameter was obtained from the L-arginine 3 mM. Total chlorophyll of L-arginine 3 mM was higher relative to other treatments. Drought stress significantly increased the activity of antioxidant enzymes. The lowest amount of phosphorus and nitrogen was observed at no foliar application ×40% FC. Therefore, according to the optimum application of water and amendment substrates, at 70% FC stress, L-arginine 3 mM and SA 100 mg /l increased the nitrogen and phosphorus content. Overall, L-arginine 3 mM and SA 100 mg /l increased the flower number and flower diameter significantly. Accumulation of these organic solutes either actively or passively helps the plants to retain water within cells and protect cellular compartments from injury caused by dehydration or maintain turgor pressure during water stress. Turgor maintenance plays an important role in drought tolerance of plants which may be due to its involvement in stomatal regulation and hence photosynthesis. Foliar application with arginine resulted in elevated proline levels and radiotracer experiments demonstrated that both 3H and 14C from arginine can be recovered as proline. The physiological relevance and the biochemical pathway of the conversion of arginine to proline in plants remain unclear. The most prominent hypothesis is that ornithine, derived from arginine catabolism, is converted by δOAT to GSA/P5C, which then serves as substrate for proline synthesis by P5CR. This model has been doubted, since Arabidopsis δOAT was found to be exclusively localized in mitochondria, while P5CR is localized in the cytosol.
Conclusion: The findings of our study showed that water stress can morphologically and physiological change C. roseus. There was no significant difference between 70% and 100% FC for root/shoot, flower number and flower diameter traits. So, we can reduce the use of water to 70% FC increased the flower number and flower diameter and can be used to alleviate the adverse impact of water stress.
H. Farhadi; M. Azizi; S.H. Nemati
Abstract
Introduction: Drought is an event that happens due to lack of rainfall in a period of time. The occurrence of drought, reduces available soil water, but water losses through evaporation and transpiration is constantly increasing. The first stage of the plant, which may be faced with drought, is ...
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Introduction: Drought is an event that happens due to lack of rainfall in a period of time. The occurrence of drought, reduces available soil water, but water losses through evaporation and transpiration is constantly increasing. The first stage of the plant, which may be faced with drought, is germinating. Since Germination begins with water uptake, lack of water at this stage in terms of duration and intensity of the stress causes or reduce germination percentage and germination rate. Because of the heterogeneity of soils in the field and lack of control of the environmental factors such as drought, laboratory research on the stress is considered. Some of these methods can be used to study the reaction of the landraces to the solutions from materials polyethylene glycol. This study aimed to investigate the characteristics of the native population of fenugreek germinating rate under drought stress conditions and identify landrace was incurred.
Materials and Methods: To investigate the effect of drought stress on germination and seedling growth characteristics of native landrace fenugreek, an experiment was conducted in a Completely Randomized Design with three replications in Seed Laboratory of University of Mashhad in 2014. The experiment treatments consisted of eight landraces of fenugreek of Esfahan, Tabriz, Hamedan, Sari, Challous, Amol, Mashhad and Yassooj on polyethylene glycol 6000 (PEG 6000) at four levels: (0, 3, 6 and 9 times) were replicated three times. The stress test for the simulation of polyethylene glycol 6000 was used and the amount of material needed to create each of the stress levels using the formula Michel and Kaufmann respectively. To (control) and distilled water was used. Landraces seed of fenugreek the city of Esfahan, Tabriz, Hamedan, Sari, Challous, Amol, Mashhad and Yassooj purchased before the start of the experiment with a three percent solution of hypochlorite for two minutes to disinfect and then were washed three times with distilled water on the twelfth day, seeds and traits such as root length and root out the Petri measure.
Results and Discussion: In the study the interactions between landrace and drought, the rate of decline in most of the traits was related to native populations of fenugreek, Tabriz, Hamadan, Sari, Challous, Amol, Yasuj and Mashhad, respectively (-9 times) compared to control (0 times). As can be seen, the Isfahan landrace was more stable in most of the traits due to changes in drought levels. On the other hand, as the drought stress increased, the percentage and rate of germination of fenugreek seeds decreased. Fenugreek seed germination rate and percentage with increased drought stress the germination rate under drought stress sensitivity was higher than the percentage of germinating. The plants grow in different stages react differently to drought show seed germination and seedling production and a dry condition indicates that the plant is a potential for drought tolerance but that does not mean that the seedlings start to grow in dry conditions, can continue to grow in the same conditions.
zainab safaei; majid azizi; Hossein aroiee; Gholamhossein davarynej
Abstract
Introduction: Nigella sativa L. is one of the herbs that has a variety of uses and has been used in Iran’s traditional medicine since old times. Today this plant is considered as one of the most important kinds of medicine. Almost all the metabolic activities of plant cells, including the construction ...
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Introduction: Nigella sativa L. is one of the herbs that has a variety of uses and has been used in Iran’s traditional medicine since old times. Today this plant is considered as one of the most important kinds of medicine. Almost all the metabolic activities of plant cells, including the construction of active ingredients in medicinal plants, depend on lack of absorbable water by plants can lead to the morphological, physiological and biochemical changes, including decrease of cell swelling and growth and thus reduction of leaf area and plant height, stomatal closure and photosynthesis restriction, increase of soluble compounds for regulating the osmotic pressure, reduction of nutrient absorption and ultimately reduction of crop production. The use of anti-transpiration compounds is considered as a promising tool for the regulation of transpiration in respect of water conservation at an optimal level, where the strategies such as the use of anti-transpiration compounds have the potential for transpiration regulation. The aim of the present study is to improve the yield and yield components of medicinal plant N. sativa by anti-transpiration compounds under drought stress conditions.
Materials and Methods: The research was done using a split plot experiment on a randomized complete block design with three replications. The irrigation intervals (8 and 16 days) in main plots and anti-transpiration compounds of chitosan (0.25, 0.5 and 1 %), Plantago psyllium mucilage (0.5, 1 and 1.5 %) and arabic gum (0.25, 0.5 and 0.75 %) were put in subplots with three replications. Also, the distance between the main plots in each block and distance between the two blocks were assigned as 100 cm and 200 cm, respectively; so that the moisture content of a plot had no effect on the adjacent plots. Planting date was April 16 and planting was performed by hand in 0.5cm-deep furrows. Anti-transpiration compounds were sprayed simultaneously with applying drought stress till the flowering stage once a week at sunset. Plant height, leaf area index, irrigation water efficiency index, leaf temperature and stomatal conductance were measured.
Results and Discussion: The results showed that there were significant differences between treatments in all studied traits. The best rate of the measured traits was observed at 8-day irrigation interval and chitosan treatment. Providing plant favorite conditions such as reducing plant temperature, increasing morphological traits comparing to rainfed at 16-day irrigation interval. Applying arabic gum did not improve growth but acted as a growth inhibitor. Anti-transpiration compounds led to significant changes in all the studied traits compared to the control, indicating the effectiveness of these natural compounds. Chitosan stimulating abscisic acid synthesis in the treated plant would result in stomatal closure, reduction of stomatal conductance, transpiration rate and water content. It also pointed out that the anti-transpiration effect of chitosan was because of its stimulatory effect in increasing abscisic acid concentration in the treated leaves of bean plant. As the above compounds are natural and biodegradable, as well as safer and less expensive than other chemical anti-transpiration compounds, they can serve as a good alternative to the chemical compounds. Cognition and expertise in water relations of plant and drought stress tolerance is considered as the main program in agriculture and the ability to withstand this stress is of great economic importance.
Conclusion: The important processes, including nutrition, photosynthes is, stomatal opening and closure and growth are all influenced by water. In this study, it was observed canopy temperature and stomatal conductance would increase at 16-day irrigation interval, where the increase is considered as a drought tolerance mechanism. Also, the anti-transpiration compounds led to significant changes in terms of all the studied traits compared to the control, indicating the effectiveness of theses natural compounds. Providing the appropriate conditions, 1% chitosan treatment can enhance the yield under drought stress. Spraying by arabic gum did not improve the growth conditions. According to this experiment, 1% chitosan treatment and 1.5% Plantago psyllium mucilage is considered the most appropriate strategy to enhance the yield of Nigella sativa under drought stress.
Esmaeil Khaleghi; Noorollah Moallemi
Abstract
Introduction: Iran is located in arid and semi-arid regions, so limitation of precipitation and poor distribution of rainfall with prolonged periods of heat and drought have caused harsh conditions for establishing plants. In general, previous researches have shown that water deficit or drought stress ...
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Introduction: Iran is located in arid and semi-arid regions, so limitation of precipitation and poor distribution of rainfall with prolonged periods of heat and drought have caused harsh conditions for establishing plants. In general, previous researches have shown that water deficit or drought stress had destructive effects on morphological, physiological and biochemical parameters of plants. So that, researchers stated that the first reaction of plants to water stress was decline in growth. Growth parameters such as height, fresh and dry weight of root and stem and leaf area could decrease with increasing water stress. Therefore, use of methods for reducing water evaporation from soil, decreasing run-off and improving transport nutrients were considered in recent years. Superabsorbant polymers are one of the most important compounds in reducing negative effects of drought on plants.
Materials and Methods: This study was conducted to investigate the effect of five different levels of super AB A200 polymer (0, 1, 2, 3, 4 g/Kg of soil) and three levels of irrigation [100 as control, 65 and 30 percentage of plant evapotranspiration potential (ETcrop)] on morphological characteristics of two olive cultivars ‘Baghmaleki’ and ‘Dezphol’ as a factorial experiment based on randomized complete block design with three replications. In this experiment, ninety 18-month-old olive trees of ‘Baghmaleki’ and ‘Dezphol’ were kept for adaptation in greenhouse for one month.The plants were planted in ninety pots including 1/3 sand, 1/3 manure and 1/3 soil with superabsorbent polymer. Superabsorbent polymers (super AB A200) were prepared from Company Rahab Resin (Licensed by Iran Polymer and Petrochemical Institute). Then, the plants were irrigated with 100%, 65% and 30% ETcrop, every three days. Finally, morphological parameters such as root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, height, leaf number, leaf Area and leaf area ratio were measured. Data analysis was performed using MSTATC software and mean comparison was done by Duncan's multiple range tests at 5 and 1% probability.
Results and Discussion: The results showed that interaction effect between irrigation and polymer affected shoot fresh weight, leaf fresh weight, shoot dry weight, leaf dry weight, height and leaf area ratio at p
Taimoor Javadi
Abstract
Introduction: Drought is a major environmental stress that affects agricultural systems and induces several physiological, biochemical and molecular responses in plants. Drought inhibits the plant photosynthesis causing changes of chlorophyll contents, damage the photosynthetic apparatus and decreases ...
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Introduction: Drought is a major environmental stress that affects agricultural systems and induces several physiological, biochemical and molecular responses in plants. Drought inhibits the plant photosynthesis causing changes of chlorophyll contents, damage the photosynthetic apparatus and decreases plant growth and development. Generally, the environmental stresses, especially drought stress, give rise to accumulation of soluble carbohydrates, proline and free amino acids as well as antioxidant compounds. Triazoles are the active ingredient of fungicides (propoconazole, penconazole, epixiconazole) and some growth regulators. The fungicidal properties of triazoles depend on inhibition of the C4-demethylase reactions in sterol biosynthesis of fungi. However, triazole-based fungicides induce a suite of morphological and physiological adaptations and allow plants to tolerate a broad range of environmental stresses including drought, herbicide treatment and elevated temperatures. The growth inhibitor paclobutrazol (PBZ) is a triazole and has been reported to protect plants against several environmental stresses, i.e. drought, low and high temperature. The purpose of this study was to evaluate the effect of palobutrazol on vegetative, physiological and gas exchange characteristics of pear (Pyrus communis cv. ShahMive) under different irrigation regimes.
Materials and Methods: In March, 2011, 1-year-old pear (Pyrus communis cv. ShahMive) saplings 80±2 cm high were planted in 20-l plastic pots filled with loamy sand soil (8% clay, 15% silt, 77% Sand) in experimental greenhouse. Paclobutrazol was added to soil at the same time with sapling cultivation at rates of 0, 0.15 and 0.3 g active ingredient per pot. PBZ was diluted in 500 ml distilled water and solution applied to the soil at the base of the saplings on pots. The control saplings were treated with distilled water of equal volume. Vegetative (stem growth, stem diameter, leaf number, shoot dry weight, root dry weight and plant dry weight), physiological and biochemical (leaf relative water content (RWC), total soluble sugar(TSS), proline and membrane stability index (MSI)) and gas exchange (Photosynthetic rate, sub-stomatal CO2, stomata conductance (gs) and transpiration) characteristics were measured.
Results and Discussion: The results showed that paclobutrazol treatments had significant effect on growth parameters, except root dry weight. Paclobutrazol significantly reduced stem height and stem diameter increment, mean leaf area, shoot dry weight and whole plant dry weight. Root: shoot ratio was increased in paclobutrazol-treated saplings. No significant differences in any characteristic were found between 0.15 and 0.3 g active ingredient PBZ per pot for growth parameter. Waters stress decreased leaf relative water content (RWC), photosynthetic rate, stomatal conductance and transpiration rate, membrane stability index and chlorophyll content and increased leaf proline content, total soluble sugar and sub-stomatal CO2. Significant interaction between PBZ and irrigation regimes was seen for RWC, proline and sub-stomatal CO2. PBZ-treated saplings had higher RWC than untreated ones. The effects of treatments on physiological and gas exchange traits were significant. RWC was high in all non-water-stressed (with or without paclobutrazol) treatments and decreased in water stressed treatments. It was higher in PBZ-treated than PBZ-untreated treatments in similar water stress condition. But there was not significant differences between 0.15 and 0.3 g PBZ in a given water stress condition. For example, RWC was 89.76 and 85.56 percent in -0.4 MPa water stress plus 0.15 and 0.3 gr PBZ treatments, respectively. The results showed that leaf proline content was increased under water stress condition. Leaf proline content of the PBZ-untreated sapling, subjected to water stress increased to 32.13 and 61.82 µmol.gr-1DW in -0.4 and -0.8 MPa water stress conditions, respectively. The PBZ-treated saplings accumulated less proline content than the PBZ-untreated ones. The highest proline concentration was founded in PBZ-untreated and -0.8 MPa water stress treatment. TSS was decreased in water stress treatments. TSS concentration was increased in water stress treatments. The highest TSS concentration was founded in PBZ-treated and untreated -0.8 MPa water stress treatments. PBZ- treated saplings had more TSS than untreated ones in -0.4 MPa treatments. Water stress was decreased leaf chlorophyll (a, b and total) content of saplings. PBZ-treated saplings had higher leaf chlorophyll content than PBZ-untreated ones in non-water stress treatments. The interaction of PBZ treatment and water stress moderated the negative effect of water stress on the chlorophyll b and total chlorophyll.
Conclusions: Generally, the results showed that PBZ allowed plants to tolerate water stress by morphological and physiological traits modification. On the other hand, paclobutrazol stimulated a more efficient stomatal regulation, which affected photosynthesis, but permitted significantly better levels of water status in treated plants.
R. Ameri; Majid azizi; Ali Tehranifar; V. Rowshan
Abstract
In order to study the effect of natural antitranspirant compound and water stress on growth, development and essential oil content of Ocimumbasilicum a factorial experiment based on completely randomized design with three replicates was conducted. 3 levels of water stress (500 as control, 375 and 250 ...
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In order to study the effect of natural antitranspirant compound and water stress on growth, development and essential oil content of Ocimumbasilicum a factorial experiment based on completely randomized design with three replicates was conducted. 3 levels of water stress (500 as control, 375 and 250 ml/day) and 3 antitranspirant compound (chitosan, plantago mucilage and psyllium mucilage) in 3 levels of 0.5, 1 and 1.5% (m/v) and applied during the plant growth. Photosynthesis, transpiration, stomatal conductance, stomatal chamber CO2, leaf temperature, fresh and dry weight of herb, essential oil percentage and content were measured. The results showed that water stress and antitranspirant application had a significant effect on all measured traits (P≤0.05 and P≤0.01). The highest values of these traits were observed in control for water stress treatment and different levels of antitranspirant compounds. Transpiration levels from leaf were significantly decreased by antitranspirant compounds application. Chitosan (1 and 1.5%) decreased transpiration by 200% over control. Photosynthesis was also increased up to 30% by chitosan treatment (0.5 and 1) in comparison to control.Also, antitranspirant compounds increasing dry matter yield in water stress condition but reducing essential oil % and yield in comparison with control. In general, according to the result of this experiment, antitranspirant compounds with natural origin are safe, biodegradable, easy available, low cost and alternatives which can be used in substitution with common chemical types.
J. Jalili; Kh. Jalili; H. Sohrabi
Abstract
One fundamental strategy for increasing efficiency of plans which aim to develop natural resources is decreasing water loss and using this restricted water optimally. In arid and semi-arid regions such as a large part of Iran, increasing period of irrigation which results in decreasing the irrigation ...
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One fundamental strategy for increasing efficiency of plans which aim to develop natural resources is decreasing water loss and using this restricted water optimally. In arid and semi-arid regions such as a large part of Iran, increasing period of irrigation which results in decreasing the irrigation costs, without causing water stress to planted sapling is a vital task. In this research we examined the effect of using super absorbent on increasing irrigation period and growth of Rose's saplings. The experiment designed in randomized block with two factors (super absorbent in 4 levels 0, 40, 90 and 140 g. and irrigation period in 4 levels 6, 10, 14 and 18 days) and 3 replications. The results indicated that using super absorbent make it possible to increase irrigation period, while surprisingly causes some increases in growth of saplings. Considering height growth of saplings, 10 days irrigation period with 40 g super absorbent and based on collar and crown growth of 14 days with 140 g. were the best treatments. It means that these treatments which implemented the minimum amount of super absorbent lead to decreasing irrigation period while growth of saplings in contract to saplings in control treatment had no significant decrease.
