Z. Falahi; S. Aliniaeifard; M. Arab; Sh. Dianati deylami
Abstract
Introduction: Postharvest handling of tropical flowers is usually difficult due to their sensitivity to cold temperatures. Anthurium(Anthurium andraeanum)is a tropical plant used in ornamental industry for its beautiful spathe and leaves. It can be produced in wide ranges of climates; in locations far ...
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Introduction: Postharvest handling of tropical flowers is usually difficult due to their sensitivity to cold temperatures. Anthurium(Anthurium andraeanum)is a tropical plant used in ornamental industry for its beautiful spathe and leaves. It can be produced in wide ranges of climates; in locations far away from their original habitats in greenhouses. Although, anthurium has long vase life compared to other cut flowers, postharvest exposure to cold temperatures makes some restrictions on its desirable vase life. This study aimed to investigate the effects of different light spectra on postharvest performance of anthurium cut flowers. Materials and Methods: Cut flowers of Anthurium andraeanum cultivars with red ('Calore') and white ('Angel') spathes were obtained from a commercial anthurium greenhouse on the morning. Anthurium cut flowers were harvested when 40-50% of the spadix true flowers were fully opened. Each flower was placed in closed flasks containing 500 mL water. Sixty flasks with cut flowers (30 cut flowers from each cultivar) were placed into chambers with exactly similar conditions but with different light spectra including white (W), blue (B), red (R) and 70% R+30% B (RB) provided by LED production modules and darkness. Each flower under light spectra was inspected and the vase life of the all flowers, change in spathe angel, spathe area, maximum quantum yield of photosystem II (Fv/Fm) and fluorescence decline ratio (RFD) were measured during 14 days exposure to 4 °C storage. Results and Discussion: Spathe 'angel' seven and 14 days following exposure to cold storage was dramatically increased in B light while the lowest changes were observed in R light of the both cultivars. Vase life of anthurium cut flowers were significantly (P≤0.01) influenced by the interaction between light spectra and cultivars. Among the light spectra, the longest vase life were observed in spathes exposed to R light in both cultivars. In 'Angel', exposure to B light dramatically shortened the vase life of anthurium cut flowers in comparison with the other light spectra. A positive relationship was detected between spathe area and vase life of cut flowers, while the relationship between spathe 'angel' and vase life was negative. No photosynthetic activity was detected on the spathe of anthurium, but the peduncle of anthurium showed the photosynthetic activity. The highest Fv/Fm and RFD values were detected in darkness and the lowest values for Fv/Fm and RFD were observed in R and RB-exposed spathes. No relationships was observed between the photosynthetic activities and the vase life of anthurium cut flowers. Although there are some reports confirmed the importance of plant growth under different light spectra on its postharvest quality, there is no report regarding the effects of light spectra on the quality of cut flowers in postharvest stage. Similar to anthurium, some reports indicated that there is no relationship between the photosynthesis and the quality of harvested products. Conclusion: Exposure of anthurium cut flowers to different light spectra resulted in alterations of morphology and quality during exposure to low temperatures. B spectrum had strong negative effects on the morphology and quality of anthurium cut flowers, while exposure to R light resulted in improvement of quality of anthurium cut flowers with less negative effects on their morphology. Spathe of anthurium had no photosynthetic activity, while its peduncle showed the photosynthetic activity. There were significant relationships between morphology and vase life of anthurium cut flowers, while no relationships were found between photosynthetic activity and their vase life. In conclusion, lighting environment during postharvest of anthurium cut flowers should be take into account for keeping their quality under low temperature conditions. Red light spectrum was introduced as the best light treatment to reduce chilling injury, increase the vase life and maintain the quality of anthurium cut flowers in both cultivars.
M.H. Sheikh Mohammadi; N. Etemadi; A. Nikbakht; M. Arab; M.M. Majidi
Abstract
Introduction: Drought and salinity are the most detrimental abiotic stresses for turfgrass growth across a wide range of geographic locations. Most cool season grass species are not well adapted to extended periods of drought and salinity stress. The decline in turf quality caused by drought and salinity ...
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Introduction: Drought and salinity are the most detrimental abiotic stresses for turfgrass growth across a wide range of geographic locations. Most cool season grass species are not well adapted to extended periods of drought and salinity stress. The decline in turf quality caused by drought and salinity stresses is a major concern in turfgrass cultivation and management. Therefore, developing management practices for improving drought and salinity resistance of turfgrasses has become imperative in arid and semiarid regions. Grass genotypes differ in their responses to drought and salinity stresses, which involve changes in morphological and physiological aspects. Understanding of relative involvement of each morphological and physiological characteristic in drought and salinity tolerance is important in selecting grass genotypes to facilitate breeding of drought and salinity-tolerant genotypes. The purposes of this research were to make selections of genotypes tolerant to drought and salinity stress for turfgrass management program.
Materials and Methods: To study some morphological and physiological responses of six Iranian crested wheatgrasses (Agropyron cristatum L.) under drought and salinity, an experiment was conducted in the greenhouse of College of Abureyhan, University of Tehran, Iran. Six Iranian Agropyron cristatum genotypes were collected from six locations in Iran. Agropyron cristatum genotypes were planted in polyvinyl chloride tubes and kept in the greenhouse. Pots were filled with sandy loam soil which had been sterilized in an oven at 160ºC for 6 h. Irrigation was applied as needed to prevent any visible stress during grass establishment. Grasses were watered three times weekly to maintain plants under well-watered conditions and soil moisture at field capacity. The experiment consisted of three treatments: 1) well-watered plants were irrigated three times per week with distilled water (control), 2) Drought stress was imposed by withholding irrigation for 45 days (drought stress), and 3) plants were irrigated daily with 100 mL of 9 dS.m–1 NaCl solution (salinity stress). To avoid primary salinity shock, the soil in each pot was drenched with 100 mL NaCl solution at incremental electrical conductivity (EC) by 3 dS.m–1 per day until the final EC reached 9 dS.m–1. Data were subjected to analysis based on a split-plot design with water treatments as main-plots and genotypes as sub-plots. Irrigation treatment as the main factor in three levels (control, drought, and salinity) and crested wheatgrass at six levels were considered as sub-plots. Studied characteristics such as height, turf quality, chlorophyll content, soluble carbohydrates, relative water content, electrolyte leakage, root penetration, and effective root depth were recorded. Statistical significance was tested using the analysis of variance procedure in SAS 9.1 (SAS Institute Inc., Cary, NC). Differences between the means were determined using the Fisher’s protected LSD test at the 5% probability level.
Results and Discussion: The results of this study showed that drought and salinity stress decreased the quality of crested wheatgrass masses, and reduced the level of quality varied among the masses. Throughout the experiment, ‘Sabzevar’ and ‘Damavand’ under drought conditions and ‘Sabzevar’, ‘Arak’ and ‘Damavand’ under salinity conditions maintained higher Turf quality compared with other genotypes. Total chlorophyll content of ‘Sabzevar’ and ‘Damavand’ were higher than other genotypes under drought and salinity conditions. The maintenance of higher chlorophyll content has been associated with better drought and salinity tolerance in plant. The soluble sugar content of ‘Sabzevar’ and ‘Damavand’ under drought conditions and ‘Sabzevar’, ‘Arak’ and ‘Damavand’ under salinity conditions were higher than other genotypes during the experiment. Soluble sugar content is an important compatible osmolyte in plants. Increased accumulation of soluble sugar content in stressed plants may be an adaptation process and resistance strategy to abiotic stresses in plants. Throughout the experiment, ‘AEKQI’, ‘Sabzevar’ and ‘Damavand’ genotypes under drought conditions and ‘Sabzevar’ genotypes under salinity conditions maintained higher relative water content in compared with other genotypes. Higher RWC indicates the ability of the leaf to maintain its higher water content under stress conditions with the simultaneous capability of the root system to take up adequate water. Based on morphological and physiological analysis for drought and salinity tolerance in investigated genotypes, the tolerance ranking would appear to be ‘Sabzevar’ > ‘Damavand’ > ‘Arak’ > ‘Urmia’ = Takestan > ‘Hashtgerd’ under drought stress and ‘Sabzevar’> ‘Arak’ > ‘Damavand’ > ‘Takestan’ = ‘Hashtgerd’> ‘Urmia’ under salinity stress. The results of this study showed that ‘Sabzevar’ and ‘Damavand’ genotypes had good tolerance to drought stress, and ‘Sabzevar’ and ‘Arak’ genotypes had good tolerance to salt stress than other Iranian crested wheatgrass genotypes.
mahdieh razaei; abbas safarnejad; mostafa arab; S.B.L Alamdari; marzieh dalir
Abstract
Introduction: Thyme is an important medicinal plant in cosmetic, pharmaceutical and food industries. The genus Thymus L. (Lamiaceae) consists of about 300 species of herbaceous perennials and subshrubs. This genus is mainly distributed over Mediterranean country, northern part of Africa and Southern ...
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Introduction: Thyme is an important medicinal plant in cosmetic, pharmaceutical and food industries. The genus Thymus L. (Lamiaceae) consists of about 300 species of herbaceous perennials and subshrubs. This genus is mainly distributed over Mediterranean country, northern part of Africa and Southern Greenland. Thymus species are commonly used as spices, herbal tea, insecticide and flavoring materials. Also, Thymus have been most frequently used in traditional herbal medicine due to its antiseptic, carminative, expectorant, antispasmodic, anti-inflammatory properties. Recent studies have showed that this genus have strong antifungal, antibacterial and antioxidant activities. Because of these medical features of this genus, Thymus is cultivated all over the world. The aromatic and medicinal properties of the genus thymus have made it one of the most popular plantsthroughout all of the world.
Materials and Methods: In order to study genetic variations, 22 populations of endemic species of Thymus include thirteen populations from species of T. daenensis, four populations of T. migricus and one population from each of the following species: T. fedtschenkoi, T. vulgaris, T. transcaspicus, T. pubsence and T. kotschyanus were used for assessment of morphology and essence value. Populations in completely random block design with three replications at the Razavi-khorasan Agriculture and Natural Resources Research Center were planted. Morphological measurement was taken on five random individuals of each replicate and average traits were analyzed. Clevenger unit was used to measure the essence amount. Morphological traits were included leaf length, leaf width, leaf number of year stem, maximum diameter of canopy, minimum diameter of canopy, canopy area, height flowering stem, height inflorescence, number of stems per plant, number days to starting of flowering, number days to 50% of flowering, fresh yield, dry yield, height of stem than inflorescence, and essence weight and volume. A balanced completely randomized design with three replications was used. Biometric measurement was applied to study the selected thyme populations. SAS, SPSS and NTSYS softwares were used for calculating the statistics indicators, normality tests, analysis of variance, means of traits, correlation coefficients, stepwise regression analysis and principal component analysis.
Result Discussion: A wide range of morphological variety was observed by biometric measurements. The results showed that there were highly significant differences between thyme populations. Mean comparison was carried out using Duncan method at 5% level. Population No.18 and population No.4 were showed the highest and the lowest diameter of canopy, respectively. Population No.18 and population No.4 exhibited maximum and minimum canopy area, respectively. Maximum and minimum stem lengths were related to populations No.12 and No.4, respectively. Maximum and minimum numbers of stems at each plant were seen in populations No.12 and No.2, respectively. Inflorescence length of population No.6 was maximum and population No.5 was minimum. The maximum and minimum average of the number of leaf per stem were observed in population No.17 and population No.12, respectively. Maximum and minimum of the leaf length were seen in populations No.10 and No.16, respectively. Population No.4 and population No.22 exhibited the highest and the lowest leaf width, respectively. For inflorescence length/ stem length ratio, population No.6 and population No.21 were showed maximum and minimum, respectively. The maximum number days to stating of flowering and 50% flowering, were seen in populations No.2 and No.8 and populations No.6 and No.4 had minimum of these. Population No.13 and population No.4 exhibited maximum and minimum dry weight, respectively. Populations No.13, No.17, No.18 and No.20 had the maximum of fresh yield and population No.4 had the minimum of fresh yield. For essence value characteristics, the most volume and weight of essential oil was observed in populations No.2, No.9, No.10 and No.18 and the least volume and weight of essential oil was observed in populations No.4, No.5, No.6 and No.12.
Conclusion: ANOVA showed that there was significant difference between thyme accessions for morphological traits which it is important for plant breeding. High variation increases selection of desirable traits for breeding. In order to crossing and hybridization, parents must be genetically distant to gain the most variation. In this study, relationship between thyme accessions using morphological and essence value traits was investigated so plant breeder can use it for production desirable hybrid.
Sh. Amini; M. Arab; majid rahemi; A.R. Rahimi
Abstract
This research was carried out in order to evaluate the influence of different concentrations of ethanol and methanol (0, 4, 6 and 12%) and two pulse treatments (12 and 24 hour) on longevity of cut standard-carnation (Sensi cultivar) in a factorial based on randomized completely design with three replications, ...
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This research was carried out in order to evaluate the influence of different concentrations of ethanol and methanol (0, 4, 6 and 12%) and two pulse treatments (12 and 24 hour) on longevity of cut standard-carnation (Sensi cultivar) in a factorial based on randomized completely design with three replications, at Tehran University, Aboreyhan Pardis, horticulture department, during 2010. The results showed that the effect of alcohol treatments and interaction effect of alcohols and pulse on vase life were significant (at what level?????), whereas solution uptake and relative fresh weight were not affected by mentioned treatments. The highest (17.33 day) and lowest (11 day) amount of carnation vase life were obtained by ethanol 12% at pulse of 12 hours and control treatments, respectively. Ethanol 6% at pulse of 24 hours, ethanol 12% and methanol 6% at pulse of 12 hours were more effective in increasing the longevity of carnation than other pulse, while in other treatments, no significant differences were observed between the pulse times. Moreover, the highest of ethylene production obtained by control, while ethanol 4% and 6% at pulse of 24 hours, ethanol and methanol 12% at pulse of 12 hours and methanol 6% at both time of pulse markedly decreased the production of ethylene and lead to significantly increase in vase life. The relative extension of flowers and relative fresh weight had a positive correlation with vase life, while solution uptake had non correlation or negative correlation with other treats.
