Atiyeh Oraee; Ali Tehranifar; Ahmad Nezami; Mahmood Shoor
Abstract
Introduction: Climate change is expected to have impacts on ecosystems worldwide. During the last 50 years, the greatest warming trends have been observed in winter months and significant increases in both the occurrence and duration of winter warming have already been reported. In general, predicted ...
Read More
Introduction: Climate change is expected to have impacts on ecosystems worldwide. During the last 50 years, the greatest warming trends have been observed in winter months and significant increases in both the occurrence and duration of winter warming have already been reported. In general, predicted future climate change scenarios will result in less than optimal cold acclimation conditions, leading to decreases in freezing tolerance and predisposition of plants to winter injury. Nonetheless, it is not clear whether water stress induced during cold hardening is of high importance in inducing freezing tolerance in plants or it is an integral part of typical cold hardening process. Since rapid and effective assessment of plant cold tolerance is important for researchers and also field trials have no regular process and have high error, different kinds of artificial freeze tests such as survival percentage test and regrowth after imposing stress have been developed.
Materials and Methods: In order to evaluate the effect of drought stress on plant freezing tolerance of viola, a factorial experiment was conducted based on completely randomized design with three replications in faculty of Agriculture, Ferdowsi University of Mashhad. Experimental factors include three water treatments (80% FC, 60 % FC and 40% FC) and 10 temperature levels (Control, from zero to -24 with 3 °C intervals). Pansy seeds sown in a nursery in the summer of 2015 and after reaching the five-leaf stage in the fall plants were transferred to the pots. After the potted plants spend cold acclimation in nature conditions, plants were subjected to water stress including control (80% FC), 60% and 40% FC for two weeks. After drought stress, whole plants were sampled for freezing tolerance assessment and they were transferred to the freezer thermos-gradient. After applying the stress, electrolyte leakage, lethal temperature 50 according to the electrolyte leakage percentage (LT50el) were measured. One months later, survival percentage, lethal temperature 50% of plant according to the survival percentage (LT50su), leaf area, number of flower and bud, dry weight (dry weight of vegetative, reproductive, root and total) and reduced dry matter temperature 50 (RDMT50) were evaluated.
Results and Discussion: Electrolyte leakage percentage (EL %) and survival (%) were significantly (p ≤ 0.01) affected by irrigation treatments in the freezing conditions. By lowering the temperature from 20 to -24 °C, the EL% significantly increased in three irrigation treatments and it increased in 80% FC compared to 60% (by 16%) at -24°C. plants under 60% FC treatment exhibited higher baseline freezing tolerance (LT50 of −18.4 °C) compared to 80% FC (LT50 of −11.8 °C).Treated plants (except 80% FC) were able to tolerate lowering the temperature to -21°C. Lowering the temperature to -24°C caused the total mortality. According to the LT50su index, 60% FC treatment was less than compared to other treatments. Leaf area significantly increased by 16%, respectively, when plants were under water deficit (60% FC) compared to 80% FC at 0 °C. The maximum number of flower were seen in 60% FC at – 3 °C and the maximum number of bud were observed at 0 °C. The results showed that dry weight was significantly (p ≤ 0.01) increased by drought stress in the freezing conditions. Plants under 60% FC at 0 °C had the highest increase (55, 62 and 64%, respectively) dry weight of vegetative, reproductive and total growth, respectively compared to control. By lowering the temperature to -18 °C in 80% FC vegetative, reproductive and root growth decreased (36, 38 and 42%, respectively) compared to control plants. RDMT50 significantly affected by drought stress. There were significantly correlation between EL with LT50el and RDMT50 (r =0.25* and r = 0.72**, respectively). In total, plants under 60% FC showed highest freezing tolerance compared to the other treatments.
Conclusions: In the current study, we found that the greatest gain in freezing tolerance was associated with cold and that the effect of drought stress on freezing tolerance varied with temperature. Drought stress resulted in an improvement in freezing tolerance of viola (lower LT50). Among the different parameters evaluated, 60% FC treatment at 0 °C most consistently induced increases in survival percentage, reproductive and vegetative growth which suggested a synergistic effect between drought exposure and low temperature. Higher dry weight of viola plants may contribute to better plant overwintering capacity. In addition, future research should explore the effect of repeated mild drought events on freezing tolerance of acclimated plants, by using strategies such as wilt-based irrigation scheduling, partial root zone drying, and deficit irrigation.
Saleh Mohammadi; Hamireza khazaie; Ahmad Nezami; Yahya Tajvar
Abstract
Introduction: Among citrus producing provinces in the country, Mazandaran province ranks first with 1.88 million tons yields. Orange is one of the horticulture crop which is sensitive to low temperature stress. Low temperature stress is one of the abiotic stresses that its negative effects is the disruption ...
Read More
Introduction: Among citrus producing provinces in the country, Mazandaran province ranks first with 1.88 million tons yields. Orange is one of the horticulture crop which is sensitive to low temperature stress. Low temperature stress is one of the abiotic stresses that its negative effects is the disruption of the electron transfer process through the thylacoid membrane. Actived oxygen radicals can be reacted with methyl unsaturated fatty acid groups and produce active fatty acid radicals. Very reactive formed radicals are capable of initiating lipid peroxidation chain reactions, which leads to the accumulation of free oxygen radicals that can lead to degradation of plant chlorophylls and membrane peroxidation and disruption of photosynthesis, accumulation of ROS, damage to cell membranes, destruction of plant pigments and nucleic acids. Plants can resist against low temperature stress by water saving and utilization of antioxidant system. The amount of free proline in many plants increases in response to environmental stresses such as cold and drought stress, and this physiological response can affect the resistance of the herbal substance under stress. Due to the diversity of citrus native genotypes in the country, the aim of this study was to determine the tolerance of native genotypes against low temperature stress in north of the country.
Materials and Methods: This experiment was conducted during the years 2015_2016 at the Citrus and Semi-Traditional Fruit Research Center in Ramsar with the aim of determining the low temperature tolerance of six native pseudo orange genotypes at 4 temperature levels (3, 0,- 3,- 6), compared to The test was carried out by Unsho and Sensitive Persian Lime (low temperature stress). Therefore, in this study, the vulnerability to low-stress conditions in controlled environmental conditions was compared with that of temperature treatments (3, 0, _3 and -6 degrees Celsius) in six genotypes of native pseudo-orange (number 1-6) sensitive cultivar (Persian lime) and resistant cultivars (Unsho) were investigated. This experiment was conducted as a factorial in a completely randomized design. The results of analysis of variance showed that temperature, genotype and interaction of these two treatments were significant in lipid peroxidation, proline, antioxidant capacity, ion leakage, hydroxylation, chlorophyll a and chlorophyll content. The temperature of the device began to decrease at a temperature of 6 ° C. The temperature of the device was 1 ° C / hour, after which the samples were kept at the specified temperatures for 3 hours and at the end of this period (3 Clock) sampling was performed to measure the traits. Accordingly, the leaf aquaculture was calculated by calculating the leaf area using a leaf surface gauge device. Ionic leakage measurements were also investigated using the method of the conversation and Meg Donald method. The presence of genotypes under cold stress led to an increase in malondialdehyde. In these conditions, due to increased oxidative activity, the accumulation of antioxidant compounds such as superoxide dismutase, glutathione peroxidase and catalase increased. The data obtained from this research were based on factorial experiment in a completely randomized design with three replications of analysis of variance and then averages were compared by Tukey test at 5% level using SAS software.
Results: Orange is a low temperature stress sensitive horticultural plant. Therefore, in this study, the vulnerability to low temperature stress in controlled environment (3, 0, 3- and -6 degrees Celsius) in six native poderotal genotypes (No.1-6) sensitive cultivars (Persian Liam) and resistant cultivars (Unsho) were studied. This experiment was conducted as a factorial in a completely randomized design. The results of analysis of variance showed that temperature, genotype and interaction of these two treatments were significant in lipid peroxidation, proline, antioxidant capacity, ion leakage, hydroxylation, chlorophyll a and chlorophyll content. Meanwhile, soluble carbohydrate was only affected by the simple factor of genotype. No effects on chlorophyll b and carotenoid pigments were significant. The highest incidences (99.33%), ion leakage (91.63%) and lipid peroxidation reaction (with a mean of 3.33 μg / kg of fresh leaf weight) were recorded in sensitive lambspeed control at 6 °C. In contrast, the highest amount of proline (32.01 mg / g leaf weight) and antioxidant capacity (73.36%) was recorded in the control group at 3 °C. Among the native pseudo-orange genotypes, in this study, different reactions were also observed under low-temperature stress conditions. Accordingly, after the control of the bird, the native pseudo-orange genotype number one was better than the one under temperature decrease. However, in most of the studied orange genotypes, in most of the destructive traits, the native pseudo-orange genotype number 6 was in the same statistical position or close to the sensitive Peninsula. The presence of genotypes under cold stress led to an increase in malondialdehyde. In these conditions, due to increased oxidative activity, the accumulation of antioxidant compounds such as superoxide dismutase, glutathione peroxidase and catalase increased.
Hamid Alipour; Mohammad Kafi; Ahmad Nezami; Amir Hossein Mohammadi
Abstract
Introduction: In Iran, main pistachio cultivation areas are located in the edge of desert. The major problem of these areas is the salinity of soil and irrigation water, which affects the growth and performance of plants and reduce yield.
Material and methods: In the present study, the effects of salinity ...
Read More
Introduction: In Iran, main pistachio cultivation areas are located in the edge of desert. The major problem of these areas is the salinity of soil and irrigation water, which affects the growth and performance of plants and reduce yield.
Material and methods: In the present study, the effects of salinity on growth characteristics and mineral contents of seedlings of seven pistachio cultivars and three genotypes (Akbari, Ahmad-Aghaei, Kaleh-Ghoochi, Fandoghi, Badami, Ebrahimi, Seyfadini and G1, G2 and G3 genotypes) were evaluated. The study was conducted in split plot based on randomized complete block design in three replications. The main plots were salinity levels of the irrigation water (0.6, 15 and 30 dS/m) by adding sodium chloride to tap water, and the sub plots were the pistachio cultivars. After germination of seeds in the lab, the seedlings were transplanted into new vases in the greenhouse. At 3rd leaf stage, the salinity treatments were imposed for a period of four months. At the end of the experiment, all samples were collected for growth and cation contents of shoots and roots and data were analyzed by analysis of variance and correlation method, using SAS statistical software and Duncan’s Multiple Range Test was employed at probability level of 5%.
Results and discussions: The results showed that increasing salinity levels reduced stem, root and leaf dry weight as well as stem height and diameter. Salinity also caused a reduction in leaf number and leaf area. At the salinity level of 30 dS/m, dry weights of root and leaf decreased by more than 70%. The length and diameter of seedlings were decreased by 17.2 % and 37.9 % under the mentioned condition. According to the measured growth characteristics, Akbari and Kaleh-Ghoochi, considered as fast growing cultivars, while G3 genotype and Seyfoddini cultivar were considered as slow growing cultivars. By increasing salinity, sodium and calcium concentrations in root, stem and leaf increased significantly, and the ratio of potassium to sodium decreased in the mentioned parts of the plant. Fandoghi and Kaleh-Ghoochi cultivars accumulated the highest amounts of sodium in leaf, while G1 and G2 genotypes had the lowest sodium level. An important fact is that G3 variety had minimum stem and leaf sodium content and maximum root sodium content. In contrast, Kaleh-Ghoochi cultivar had maximum leaf sodium content and minimum root sodium content. This obviously indicates that G3 variety accumulates sodium in the root and avoids sodium transmission to stem and leaf, and Kaleh-Ghoochi variety acted conversely. G2 genotype and Kaleh-Ghoochi variety contain the highest (3%) and lowest (1.4%) levels of leaf potassium. At salinity levels of 15 and 30 dS/m, the index of potassium to sodium ratio decreased by 93% and 87%, respectively, in comparison to the control salinity level (0.6 dS/m2). Generally, local genotypes of pistachio (G1, G2 and G3) showed lower sodium absorption and transport to leaf, while G3 genotype had the highest sodium content in the root and the lowest concentration of sodium in stem and leaf. G2 genotype and Ahmad-Aghaei cultivar had the highest leaf potassium to sodium ratios of 7/8 and 6/3, respectively, while Kaleh-Ghoochi cultivar had the lowest leaf potassium to sodium ratio (3/95). It seems that Kaleh-Ghoochi, Fandoghi and Akbari cultivars are relatively sensitive and G1, G2 and G3 genotypes and Ahmad-Aghaei cultivar are relatively tolerant to salinity at seedling stage. Results of correlation analysis showed a significant negative correlation between the levels of salinity and growth characteristics of pistachio. Leaf sodium content has a significant negative correlation with leaf potassium content as well as the potassium to sodium ratio in root, stem and leaf. Reduced or stunted growth of the pistachio seedlings can be a result of water stress as well as sodium and chlorine toxicities. The impaired balance of nutrient uptake through the root in salt stress conditions leads to reduced growth characteristic of the pistachio seedlings. As the salinity of the irrigating water increases, concentrations of sodium and chlorine ions in soil solution increases, therefore, balance of nutrients is impaired and the root absorption of sodium and chlorine increases and potassium uptake decreases. Hence, the concentrations of sodium and chlorine ions increased in root, stem and leaf, andpotassium concentration decreased. Salinity tolerance in many plants is attributed to non-transmission or limited transmission of sodium to aerial parts of the plant. Various pistachio cultivars acted differently in absorption and accumulation of these elements in the parts of plant. The pistachio varieties with less sodium absorption and transmission to the leaf, but more potassium absorption and transmission, increased potassium to sodium ratio in the leaf and showed more tolerance to salinity. The mechanism is not clearly recognized, perhaps sodium is re-absorbed from the xylem sap and remained in the root and stem, without transmission to leaf. A similar mechanism probably occurs in local genotypes of pistachio (G1, G2, and G3) and results in improved tolerance to salinity.
Elham Azizi; Asiyeh Siahmarguee; Ahmad Nezami; Ali Asghar Mohamad Abadi; Reza Soheili
Abstract
In order to investigate the possibility of Fennel autumnal sowing in Mashhad condition, 2 sets of experiments were conducted in Agricultural College, Ferdowsi University of Mashhad in 2003-2005. This experiment was performed in the manner of Split Blocks based on completely randomized Blocks with three ...
Read More
In order to investigate the possibility of Fennel autumnal sowing in Mashhad condition, 2 sets of experiments were conducted in Agricultural College, Ferdowsi University of Mashhad in 2003-2005. This experiment was performed in the manner of Split Blocks based on completely randomized Blocks with three replications. Treatments were two fennel ecotypes (Khorasan and Kerman) and three planting dates (October, December and March). Fennel seeds only were planted in 2003 and in next year, plants were grown of remains parts of stem in surface of soil. Results showed in end of first years, number of remain plant in March planting dates, three times of October planting dates. In second years, number of remain plant in March planting dates 6.5 and 2.7 times October and December planting dates, respectively. Number of remain plant between Khorasan and Kerman ecotypes were not significantly different in two years. However, effects of planting date and ecotype on dry matter and number of primary and secondary branches were not significant but plant of October planting dates superior to the plant of December and March planting dates. Number of umbel without seed in October planting dates was 3.4 and 8.8 times of December and March planting dates. In spite of weight of seed in October planting dates highest than December and March planting dates, effect of planting dates on weight of seed in plant was not significant. In first year highest and lowest yield were obtained in October (68.7 gr/m2) and March (20.5 g/m2) planting dates. But in second year maximum and minimum of yield were obtained in March and October planting dates with 45.3 and 14.2 g/m2, respectively.
Ahmad Nezami; Seyed Mohammad Javad Mousavi; Somaye Nezami; Ebrahim Izadi Darbandi; Maryam Yousef Sani; Fatemeh Keykha Akhar
Abstract
Calendula (Calendula officinalis) is relatively cold tolerant plant, but in some years plant seriously injured due to harsh winter. In order to evaluate freezing tolerance of calendula an experiment was carried out at college of Agriculture, Ferdowsi University of Mashhadin a factorial-completely randomized ...
Read More
Calendula (Calendula officinalis) is relatively cold tolerant plant, but in some years plant seriously injured due to harsh winter. In order to evaluate freezing tolerance of calendula an experiment was carried out at college of Agriculture, Ferdowsi University of Mashhadin a factorial-completely randomized design with three replications and plants of two sowing dates (summer and autumn) were exposed to12 temperatures (0, -2, -4, -6, -8, -10, -12, 14- ,16-, -18, -20 and -22oC). Seeds of calendula plants were sown in summer (summer plant) and autumn (autumn plant) in the bed and in six to eight-leaf stages were transplanted to the pots. After the cold acclimation in natural condition, freezing stress was applied with using a thermo gradient freezer. To employ stability of cytoplasmic membrane, percentage of electrolyte leakage (EL%) was measured after freezing. Also survival percentage (Su%) and regrowth of calendula plants determined after three weeks recovery. Leaves EL% in autumn plants was significantly more than summer plants and autumn plants have higher Su%, but plant height, number of lateral branches, numbers of reproductive traits, total dry matter, vegetative and reproductive dry matter in summer plants were more than autumn plants. However, there were no difference between calendula plants for LT50el in both autumn and summer plants, but there was significant difference between them for LT50su and total dry matter, and LT50su and reduced dry matter temperature50 (RDMT50)for summer plants were -18.6 oC and -11.3 oC and for autumn plants were -19.4 oC and -13.7 oC, respectively.
Ali Eskandari; Hamid Reza Khazaie; Ahmad Nezami; Mohammad Kafi; Abbas Majdabadi
Abstract
Abstract
In order to Study the effects of irrigation regimes on physiological traits, yield and water use efficiency of potato (Solanum tuberosum L.) in Mashhad weather condition, an experiment was conducted in 2009 at research field of the College of Agriculture, Ferdowsi University of Mashhad, using ...
Read More
Abstract
In order to Study the effects of irrigation regimes on physiological traits, yield and water use efficiency of potato (Solanum tuberosum L.) in Mashhad weather condition, an experiment was conducted in 2009 at research field of the College of Agriculture, Ferdowsi University of Mashhad, using factorial experiment based on randomized complete blocks design with 3 replications. Experimental factors were 3 irrigation regimes including: I1: provided with 100% of water requirement of potato, I2: provided with 70% of water requirement of potato applied before tuber initiation and I3: provided with 70% of water requirement applied at all growth period of potato as first factors and 3 potato cultivars (Agria, Almera and Sinora) as second factors. The results indicated that about physiological traits when provided with 100% water requirement of potato the highest of relative water content, quantum efficiency of photosystem II, leaf area index and canopy height related to this irrigation regime. Even though with reduce in irrigation volume because of decreasing in LAI, the SPAD index in some cases was higher. Also in all irrigation regimes total tuber yield of Agria cultivar was better than to others. Considering to the calculation of water use efficiency with 30% decreasing in irrigation volume before tuber initiation, Agria had the highest WUE in provided with 70% water requirement. Finally, it seems that with decreasing in irrigation volume at Mashhad weather condition, Agria had the best growth and more acceptable yield compared to other genotypes.
Keywords: Potato, Irrigation regimes, Cultivar, Water Use Efficiency
Asiyeh Siahmarguee; Golsoomeh Azizi; Ahmad Nezami; Maryam Jahani Kondori
Abstract
Abstract
In order to investigate the freezing tolerance of field grown Fennel (fueniculum vulgare mill) under controlled conditions, a factorial experiment based on completely randomized design was conducted with three replications in Agricultural College, Ferdowsi University of Mashhad in 2004. Treatments ...
Read More
Abstract
In order to investigate the freezing tolerance of field grown Fennel (fueniculum vulgare mill) under controlled conditions, a factorial experiment based on completely randomized design was conducted with three replications in Agricultural College, Ferdowsi University of Mashhad in 2004. Treatments were two fennel ecotypes (Khorasan and Kerman), two planting dates (Oct 8th and 29th ) and six temperatures (0,-3,-6,-9,-12,-15°C). Plants were harvested from the field on Des 7th in controlled conditions exposed to the freezing temperature. Plant survival percentage and re growth after 21 days under the greenhouse and plant necrosis degree after the six days under the lab condition were evaluated. Greenhouse results showed that there wasn’t significantly different between Khorasan and Kerman ecotypes for survival percentage, height and number of nod but Kerman ecotype had the higher leaf number than Khorasan ecotypes. Planting date had significantly effect on survival percentage, height, number of leaf, number of nod and percentage of plant dry weight. So 29 October planting date was higher than 8 October in the entire measured criteria. With lowering the temperature, survival percentage, height, number of leaf, number of node and dry weight had decreased trend. There was significantly different between planting dates on plant necrosis degree of plant in 6th day under the lab conditions. Necrosis degree for 29 October and 8 October. planting date was 3.4 and 2.8% respectively. The highest necrosis degree was shown in -150C freezing treatment that it was twice than necrosis degree in 00C .
Keywords: Height, Necrosis degree, Survival percentage, Dry weight
Ronak Sasani; Hamid Reza Khazaei; Ahmad Nezami
Abstract
Abstract
Dormancy in potato minituber buds is one of the limiting factors on planting them after harvesting. This study was undertaken in a completely randomized Nested with arrengment three replications to examine the effective hormonal and temperature treatments on rapid breaking of minitubers dormancy ...
Read More
Abstract
Dormancy in potato minituber buds is one of the limiting factors on planting them after harvesting. This study was undertaken in a completely randomized Nested with arrengment three replications to examine the effective hormonal and temperature treatments on rapid breaking of minitubers dormancy at 2008. Treatments included gibberellic acid (2 and 5 mg/l), benzyl adenine (5 and 10 mg/l), zeatine (1.5 and 3 mg/l) and temperature (5, 10 and 15oC). Results showed that germination rate and percentage, length of sprouts, number of active sprouts, tuber weight were affected by hormonal and temperature. Germination rate and percentage were not significantly different amoung hormones under temperature 15oc but lowest was respectively 14.4 and 11 for control. Most effect on length of sprouts was resulted in 5 mg/l gibberellic acid. Temperature 10oc had most affect on number of active sprouts. Under low temperature effect of hormones on studied was not significant. Loss of Tuber weight under low temperature (5oc) and high temperature (15oc) was high and low respectively.
Key words: Potato, Dormancy of minituber, Dormancy breaking
