Somaye Amraee Tabar; Ahmad Ershadi
Abstract
In this study, the drought tolerance threshold and relationships between some biochemical and physiological responses of two stone fruit rootstocks, Cadaman and GF677, have been investigated. For this purpose, a pot experiment has been carried out in a greenhouse using factorial trial based on a completely ...
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In this study, the drought tolerance threshold and relationships between some biochemical and physiological responses of two stone fruit rootstocks, Cadaman and GF677, have been investigated. For this purpose, a pot experiment has been carried out in a greenhouse using factorial trial based on a completely randomized design with three replications. One-year-old rooted cuttings of two rootstocks are exposed to drought stress (-0.1 (control), -0.6, -1.1, -1.6 MPa) by adding different amounts of polyethylene glycol-6000 to Hoagland nutrient solution. Significant increase in electrolyte leakage and decrease in leaf relative water content of Cadaman and GF677 rootstocks has occurred at -0.6 and -1.1 MPa, respectively. Concentration of photosynthetic pigments and quantum yield of photosystem II (FV/FM) are less affected by drought stress, decreasing significantly in Cadaman and GF677 rootstocks at -1.1 and -1.6 MPa, respectively. Under severe drought stress, photosynthesis, transpiration, intercellular CO2 concentration, and stomatal conductance in Cadaman rootstock decline more considerably, compared to GF677. Moreover, at drought stress of -1.6 MPa, GF677 does not significantly reduce its photosynthesis, despite a substantial decrease in transpiration; however, the relative decrease in photosynthesis of Cadaman at -1.6 MPa has been much greater than the relative decrease in its transpiration and intercellular CO2 concentration, which, in turn, results in a drop in water use efficiency and mesophilic conductance of Cadaman leaves, compared to GF677. It seems that considerable reduction in photosynthesis in Cadaman rootstock, along with stomatal limitations, is largely due to non-stomatal constraints such as loss of cell membrane intact and reduction of chlorophyll, carotenoids and chlorophyll fluorescence. Results show that GF677 rootstock has higher tolerance to severe drought stress, compared to cadaman.
Nabi Hadavand; Ahmad Ershadi; Rohollah Karimi; Alireza Talaei; Mohammad Ali Askari Sarcheshmeh
Abstract
High-density planting system is one of the effective methods for improving production and profitability of tree orchards. In this research, the effects of four planting densities (1904, 2666, 3137 and 4800 tree/ha) on annual shoot growth, Physicochemical properties of fruit and leaf mineral contents ...
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High-density planting system is one of the effective methods for improving production and profitability of tree orchards. In this research, the effects of four planting densities (1904, 2666, 3137 and 4800 tree/ha) on annual shoot growth, Physicochemical properties of fruit and leaf mineral contents of apple (Malus domestica Borkh cv ‘Granny Smith’) tree grafted on M26 clonal rootstock were studied in randomized complete block design with four treatments and four replications in College of Agriculture and Natural Resources, University of Tehran, during 2009-2010. Based on results, planting density significantly affected some qualitative characteristics such as fruit length, fruit diameter, total soluble solid, fruit dry matter, fruit ash and sun scald, but no significant effect on fruit weight, fruit L/D ratio, TA and tenacity were observed. Planting density significantly affected the leaf N and Fe concentrations. The highest N (1.81 percent) and Cu (39 µg/kg) the lowest Fe of leaves (237 µg/kg) was observed with 1904 tree/ha. Although, planting density had no significant effect on other mineral elements, but with increasing the planting density, leaf P, K, Mg and Mn content increased, but, Ca and Cu decreased. Increasing in N and Fe was associated with a decrease and increase of current seasonal shoot growth, respectively. Likewise, trees with higher crop tend to have more N and less Fe. These results showed that, under Iran climatic condition, with increasing in planting density of apple orchardit can be produced higher fruit crop without decrease in its quality parameters.
Somaye Amraee Tabar; Ahmad Ershadi; Tahmine Robati
Abstract
This study was performed to investigate the effect of Putrescine and Spermine on some physiological and biochemical characteristics and antioxidant enzymes activity of peach (Prunus persica cv. Alberta) and almond (Prunus dulcis cv. Rabi) seedlings under water deficit. The first factor was water regime ...
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This study was performed to investigate the effect of Putrescine and Spermine on some physiological and biochemical characteristics and antioxidant enzymes activity of peach (Prunus persica cv. Alberta) and almond (Prunus dulcis cv. Rabi) seedlings under water deficit. The first factor was water regime at two levels (80% or 50% of soil available water), and the second factor was polyamine treatments (putrescine 0.1, putrescine 1, spermine 0.1, spermine 1 mM and control). Water deficit led to increased electrolyte leakage percentage in peach leaves, compared to almond. Under water deficit, polyamines reduced electrolyte leakage in both plants, Spermine was more effective than Putrescine under water deficit. Leaf contents of soluble carbohydrates, proline and soluble proteins in almond more increased as compared to peach. Spermine more effectively increased concentration of osmoregulants, compared to Putrescine. Under water deficit, the activities of catalase, guaiacol peroxidase and ascorbate peroxidase enzymes increased in both plants, higher enzyme activity was found in almond leaves in comparison with peach. The maximum antioxidant enzyme activity was found following spermine treatments. Application of spermine and putrescine increased drought tolerance in almond and peach through reducing the electrolyte leakage, increasing compatibility osmolytes and antioxidant enzyme activity.
Razieh Rostami; Ahmad Ershadi; Hasan Sarikhani
Abstract
In order to evaluate tolerance of four Prunus rootstocks to Fe-deficiency-induced Chlorosis, an experiment was carried out in Bu-Ali Sina University in 2012 using a RCBD design with four replications. Four rootstocks were used, including GF677, GN15, bitter almond and peach and nutritional treatments ...
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In order to evaluate tolerance of four Prunus rootstocks to Fe-deficiency-induced Chlorosis, an experiment was carried out in Bu-Ali Sina University in 2012 using a RCBD design with four replications. Four rootstocks were used, including GF677, GN15, bitter almond and peach and nutritional treatments were: Hoagland solution without Fe (pH = 6), Hoagland solution containing 90µM Fe as control (pH = 6), and Hoagland solution containing 90 µM Fe + 10 mM KHCO3 (pH = 8). At the end of experiment, total and active content of iron in leaves and roots, chlorophyll content, hydrogen peroxide levels as well as catalase and ascorbate peroxidase enzyme activity were measured. Based on the results, peach was the most sensitive rootstock to iron deficiency and bicarbonate treatments, while almond was the most tolerant rootstock. Comparing two peach × almond hybrid rootstocks showed that GF677 had better performance under iron deficiency and in the presence of bicarbonate rather than GN15. Bicarbonated nutrient solution inhibited the Fe absorption and transport by peach roots, whiles other rootstocks uptake high amount of iron and transferred it to shoots. In this condition, on both peach-almond hybrids, GF677 and GN15, large amounts of iron in leaves were in inactive form but on bitter almond rootstock in addition to high iron uptake and transport, large amounts of this element was active and utilizable by leaves.
Shima Chayani; Ahmad Ershadi; Hasan Sarikhani
Abstract
Delaying bud break, using chemicals is an approach to avoid spring frost damage. Therefore, the effect of spraying different concentrations of soybean oil and naphthalene acetic acid (NAA) on delaying bud break, altering internal atmosphere and cold hardiness in grape cultivar ‘Fakhri’ was ...
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Delaying bud break, using chemicals is an approach to avoid spring frost damage. Therefore, the effect of spraying different concentrations of soybean oil and naphthalene acetic acid (NAA) on delaying bud break, altering internal atmosphere and cold hardiness in grape cultivar ‘Fakhri’ was studied in 2011 in a commercial vineyard in Maryanaj, Hamedan using a factorial trial based on randomized complete block design with three replications. Selected branches were pruned to six buds. The concentration of carbon dioxide and ethylene gases in the buds were measured three days after spraying. Results showed that spraying 10 percent soybean oil alone or in combination with 100 mg/l naphthalene acetic acid caused the highest concentration of carbon dioxide and ethylene in buds, delayed bud bursting for 12 days and improved cold resistance of buds by 5°C. Auxin had minor impact on delaying opening and increasing cold tolerance of buds, while five percent soybean oil alone or in combination with NAA had intermediate effect. Applying oil treatments in March had more considerable effect on delaying bud opening and CO2 and ethylene accumulation, compared to April spraying. It seems that applying soybean oil prolongs bud dormancy due to increasing respiratory gases accumulation which subsequently delays bud break and resulted in decreased spring frost damage.
Shiva Bazl; Rouholah Karimi; Ahmad Ershadi; Alireza Shahbodaghlo; Mousa Rasouli
Abstract
Cold stress is one of the limiting factors in production of greenhouse vegetables. Chemicals offer useful approach to reduce low temperature-induced damages. This study was conducted to evaluate the effect of foliar application of methyl jasmonate (MeJA) at concentrations of 0 (control), 50, 100, 200 ...
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Cold stress is one of the limiting factors in production of greenhouse vegetables. Chemicals offer useful approach to reduce low temperature-induced damages. This study was conducted to evaluate the effect of foliar application of methyl jasmonate (MeJA) at concentrations of 0 (control), 50, 100, 200 µM) on electrolyte leakage (EL), relative water content (RWC), soluble carbohydrates, proline, chlorophyll content and chilling index of greenhouse- grown cucumber (Cucumis sativus L. cv ‘Negin’) in 4-6 leaf stage. MeJA was sprayed two times/day on cucumber seedling in a greenhouse of Bu-Ali Sina University, as a factorial based on completely randomized design with five replications per treatment, inlate- summer of 2013. Two days after spraying, seedlings were transferred from 25ºC to cold chamber and were subjected to chilling treatments of 15, 10 and 5 ºC for 4 hours. The EL of all plants increased with reducing the temperature. However, in MeJA-treated plants, especially in application of 200 µM, a lower leaf EL was observed. A clear increase in soluble carbohydrates and proline concentration was observed with decreasing temperature from 15 to 5ºC in all plants while in MeJA -treated seedlings, especially in application of 200 and 100µM, a greater amount of these osmolytes were observed in compared to control. Moreover, exogenous application of MeJA reduced RWC and visual damage of cold-stressed seedlings but increased chlorophyll content in compared to control plants. These changes correlated with the increment of cold tolerance in the cucumber plants. The results indicated that MeJA application especially at 200 µM, has the capacity to improve chilling tolerance of seedlings and can be used as a prophylactic tool to protect against chilling injury of cucumber cultivars in greenhouses
Rouhollah Karimi; Ahmad Ershadi; Mahmoud Esna-Ashari; Masoud Mashhadi Akbar Boojar
Abstract
Screening of native cultivars and understanding of the mechanisms involved in cold hardiness in grapevines is needed to match cultivars appropriately with growing sites and aid in breeding and selecting cultivars with improved freezing tolerance. In this study cold hardiness of fifteen grapevine (Vitis ...
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Screening of native cultivars and understanding of the mechanisms involved in cold hardiness in grapevines is needed to match cultivars appropriately with growing sites and aid in breeding and selecting cultivars with improved freezing tolerance. In this study cold hardiness of fifteen grapevine (Vitis vinifera L.) cultivars were evaluated using tetrazolium stain test and post freezing budbreak assays during six months from acclimation till deacclimation stages. Moreover, seasonal changes pattern in soluble proteins, total phenol and Malondialdehyde (MDA) of buds were measured during this period. Significant differences (P≤0.01) were found among cold hardiness of cultivars in all stages. ‘Bidaneh Ghermez’ and ‘Khalili’ (LT50= -22 and -22.6 ºC in respectively) were the hardiest ‘Ruby’ and ‘Perlette’ (LT50= -16.1 and –16.9 ºC in respectively) were the least hardy cultivars in January. Soluble proteins and total phenol concentrations of buds increased during cold acclimation from November to January then decreased in March. The concentration of these compounds was higher in cold hardy such as ‘Bidaneh Ghermez’ and ‘Khalili’ cultivars than least hardy ones, indicating the positive relationship of these compounds with freezing tolerance. The measured MDA in onset and end of dormancy period was lower than its concentration in deep dormancy in January. Lower MDA concentration was found with cold hardy cultivars ‘Khalili’ and ‘Bidane Ghermez’ in comparison with cold sensitive cultivars, ‘Perlette’ and ‘Yaquti’. Our results indicated that high accumulation of soluble proteins and total phenol in cold hardy cultivars resulted in improved membrane stability and freezing tolerance.
Ahmad Ershadi; Samira Taheri
Abstract
Frost in early spring is one of the limiting factors in the production of grape. Chemicals offer useful approach to reduce low temperature-induced damages. Different concentrations of salicylic acid including: 0 (control), 0.5, 1 and 2 mM were sprayed twice on 10 year-old ‘Bidaneh Sefid’ ...
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Frost in early spring is one of the limiting factors in the production of grape. Chemicals offer useful approach to reduce low temperature-induced damages. Different concentrations of salicylic acid including: 0 (control), 0.5, 1 and 2 mM were sprayed twice on 10 year-old ‘Bidaneh Sefid’ grape vines at full bloom stage and changes in leaf soluble carbohydrates, proline and protein levels were measured in the next day morning. Leaf and stem samples were subjected to low temperatures of 0, -2, -4 and -8°C while flower clusters were exposed to temperature of 0, -2 and -4°C for three hours. Salicylic acid at 0.5mM concentration resulted in the highest amounts of soluble carbohydrates while the maximum proline content was observed with 0.5 and 1mM concentrations. Salicylic acid at 2mM concentration caused a decrease in soluble protein level. Salicylic acid, low temperature and their interactions had a significant effect on electrolyte leakage of different tissues. Salicylic acid treatments led to a reduction in electrolyte leakage of stem, leaf and cluster samples, compared to control. It seems that salicylic acid minimizes the negative effects of low temperature with evidence of less membrane damage by up-regulating the accumulation of osmoregulants such as soluble carbohydrates and proline.