Mohammad Soleimani; Mostafa Mobli; Ali Akbar Ramin; Bahram Baninasab; Leila Aslani
Abstract
Introduction: Cold stress is one of the limiting factors for plant growth and yield production in most parts of the world. Cold stress damages cells through changes in the activity of macromolecules, decreasing osmotic potential, and significant changes in other parts of the cell. Cold stress in young ...
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Introduction: Cold stress is one of the limiting factors for plant growth and yield production in most parts of the world. Cold stress damages cells through changes in the activity of macromolecules, decreasing osmotic potential, and significant changes in other parts of the cell. Cold stress in young seedlings generally reduces leaf development, induces wilting and chlorosis and in more severe cases, browning and necrosis become visible. Cucumber is a sensitive plant to low temperature and its cultivation, except the southern and central parts of Iran, occurs in areas where there is a possibility of cold stress in the early part of the growing season due to the low temperature. The different ways for controlling cold stress had been used; one of them is using plant growth regulators such as spermidine. Spermidine is one of the polyamines that has been used in recent years to control cold stress. The effect of cold treatment on the amount of indigenous leaf polyamines has been reported differently between cold-resistant and sensitive cucumber cultivars. During the cold stress, the amount of indigenous spermidine in leaves of cold-resistant cucumber cultivars and sensitive cultivars increased significantly and remained unchanged, respectively. The increase in the content of putrescent, spermidine and spermine in cold resistant cultivars during cold stress was probably due to the increased activity of ornithine decarboxylase (ODC). The amount of polyamines in chickpea plants that were exposured to low temperatures (12-15°C and 4-6°C are related to mean maximum and minimum temperature of the farm, respectively) increased six to nine times. Adding spermidine to the cucumber growing medium before applying cold treatment increased spermidine amount in all organs and increased cold tolerance.
Materials and Methods: To study the effect of spermidine on cold tolerance of cucumber, seedling of ‘Rashid’ cultivar, an experiment was conducted based on completely randomized design with four replications and four treatments consist of different concentrations of spermidine (0, 0.1, 0.5 and 1 mM) in incubator of College of Agriculture, Isfahan University of Technology. So seeds were exposed to 20°C for 7 days in a humid condition and then were treated with 0, 0.1, 0.5 or 1 mM spermidine, the remaining 8 days they were kept at 6 or 9°C. The treatments performed in dark conditions until the second day of germination and received 8 hours of light daily from the third day until the end of the experiment. At the end of each experiment, shoot and root length were measured by use of the ruler, shoot and root fresh and dry weight were measured by use of digital scale, shoot and root ion leakage were measured based on Lates method (3) and shoot and root proline concentration were measured based on Bites et al., (2) method. To compare the effects of temperature and its interactions with spermidine, data of two experiments analyzed as split plot experiment (Different temperatures and spermidine concentrations were as main and subplots, respectively).
Results and Discussion: The findings of this study showed that application of the highest concentration of spermidine (1 mM) in 9°C had the inverse effect on cold tolerance, so it decreased the fresh and dry weight of root. In 6°C, 0.5 mM spermidine was more effective than other concentrations, and it increased root fresh weight, shoot proline concentration and decreased root ion leakage. It has been shown that the non-saturated lipid profile of membranes of cold-resistant plants in comparison of non-resistant plants is significantly increased, and this increase is associated with a decrease in cell ion leakage. Proline works as a nitrogen source and soluble substance that helps the plant to combat again stress conditions. The split-plot analysis of data showed that 0.5 and 0.1 mM spermidine treatments increased root length, root fresh and dry weight significantly. The study of spermidine concentrations ×temperatures showed that the increasing effect of 0.5 mM spermidine on root length, root fresh and dry weight was only visible in 6°C.
Reza Aminpour; Mostafa Mobli; Ahmad Mortazav Bak
Abstract
Abstract
In order to study the adaptability and bulb yield characteristics of 12 short day onion cultivars for sowing in autumn in Isfahan, an experiment was conducted at Kabootar Abad Research Station of Isfahan during two growing seasons (2007-2008 and 2008-2009). The experimental design was Randomized ...
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Abstract
In order to study the adaptability and bulb yield characteristics of 12 short day onion cultivars for sowing in autumn in Isfahan, an experiment was conducted at Kabootar Abad Research Station of Isfahan during two growing seasons (2007-2008 and 2008-2009). The experimental design was Randomized Complete Blocks with four replications. Cultivars included: 1- Pegasus, 2- Grano 6835(XP 0759 6835), 3- Hyb. Cirrus, 4- Texas Early White, 5- Hyb. Jaguar, 6- Century (EX 0759 2000), 7- Calera, 8- Hyb. Primavera, 9- Lahoya, 10- Texas Yellow Grano 502 (common cv. in region), 11- Contessa and 12- Hyb. Savannah Sweet. Seed were sown in early October and common cultural practices were followed. Analysis of variances showed that the effect of year was not statistically significant. Results showed that Hyb. Cirrus produced significantly the highest total (109.39 t/ha) and marketable yield (94.47 t/ha) and Lahoya produced the lowest total (28.19 t/ha) and marketable yield (16.17 t/ha). Total and marketable yield in Texas Yellow Grano 502 were placed after cirrus. Bulb diameter and bulb height decreased as bulb yield decreased. Among cultivars, Hyb. Jaguar with 4.66 mm and Lahoya with 2.58 mm had the thickest and thinnest bulb neck, respectively. Hyb. Contessa produced the highest bulb dry matter (10.38%) and total soluble solids (10.70%). The lowest DM and TSS were belonged to Primavera and Savannah Sweet respectively. There was a significant correlation between DM and TSS (r = +0.71). In conclusion, Hyb. Cirrus showed good adaptability and performed better than the other cultivars in Isfahan area.
Keywords: Onion, Short day cultivars, Adaptability, Bulb yield, Dry matter, Total soluble solids
Negar Simkeshzadeh; Mostafa Mobli; Nematollah Etemadi; Bahram Baninasab
Abstract
Abstract
Planting of olive (Olea europaea L.) tree due to salt and drought tolerance and ever green habit increasingly is considered in urban landscape in recent years. The low resistance to cold has been a major problem in using this tree in temperate and cold zones. So, determination of frost resistance ...
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Abstract
Planting of olive (Olea europaea L.) tree due to salt and drought tolerance and ever green habit increasingly is considered in urban landscape in recent years. The low resistance to cold has been a major problem in using this tree in temperate and cold zones. So, determination of frost resistance cultivars is one of the important measures for use of this tree in urban landscape. To evaluate frost resistance of 15 olive cultivars and to compare the visual assessment and chlorophyll fluorescence methods, a factorial experiment was carried out using 7- year- old olive trees which were planted in randomized complete block design with 3 replications. In visual method, frost damage of winters 2007 and 2008 to plants (percentage of drying by scoring and percentage of leaf abscission) were measured. Results of this experiment showed that ‘Amphisis’ followed by 'Gorgan' and 'Shengeh' were tolerant and ‘Kroneiki’ and ‘Rashid’ were sensitive cultivars to low temperatures. In method of chlorophyll fluorescence, in July 2008 leave samples of each cultivar was gradually incubated in 0, -5, -10, -15 and -20 ° C for one hour at least. Then Fv/Fm value of each sample was measured with fluorescence spectrometer. Results indicated that 0 and -5 ° C had no damage on samples and all cultivars tolerated these temperatures (Fv/Fm> 0.83). When temperature reduced to -10 and -15 ° C the stress on plants increased and ‘Rashid’ showed the lowest Fv/Fm (0.243 and 0.001 respectively) and was the most frost sensitive. Decreasing temperature to -20 °C had no further significant effect on reduction of Fv/Fm index and showed no difference between cultivars. Based on this method, ‘Shengeh’, ‘Gorgan’ and ‘Amphisis’ were tolerant cultivars and ‘Rashid’, ‘Spain’, ‘Manzanilla’ and ‘Kroneiki’ were sensitive cultivars to low temperatures which confirmed the results of visual assessment.
Keywords: Chlorophyll fluorescence, Frost resistance, Olive, Visual assessment
Fatemeh Shakeri; Bahram Baninasab; Sirus Ghobadi; Mostafa Mobli
Abstract
Abstract
To investigate the effects of paclobutrazol (PBZ) on vegetative and reproductive growth of Strawberry cv. Selva a factorial experiment in a completely randomized design with three replications was carried out in greenhouse of Agriculture College, Isfahan University of Technology. PBZ was applied ...
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Abstract
To investigate the effects of paclobutrazol (PBZ) on vegetative and reproductive growth of Strawberry cv. Selva a factorial experiment in a completely randomized design with three replications was carried out in greenhouse of Agriculture College, Isfahan University of Technology. PBZ was applied in two methods, drench and foliar spray, at 0, 0.5, 1, 1.5 and 2 mg active ingredient per plant. The results indicated that applications of PBZ as foliar spray was more effective than soil drench on vegetative and reproductive growth. With increasing the amount of PBZ leaf area, shoot fresh weight, whole plant fresh weight and petiole length of treated strawberries were decreased, however fresh weight, number and diameter of roots were not affected by PBZ. Also PBZ had no significant effect on fruit firmness, total soluble solids and vitamin C. The interaction of PBZ and its method of application on characteristics including leaf area, petiole length and diameter, total fresh weight, shoot fresh weight, leaf chlorophyll content, yield, fruit diameter and harvest index were significant. Foliar application of PBZ at the rate of 2 mg active ingredient per plant lead to maximum value of petiole diameter, leaf chlorophyll content and harvest index. Yield (fruit/plant) was also increased (27.16%) when the plants received 1 mg active ingredient per plant PBZ through soil drench method.
Key words: Paclobutrazol, Strawberry, Soil application, Foliar application
Reza Aminpour; Seyyed Farhad Mousavi; Mostafa Mobli
Abstract
Abstract
In order to study the effects of irrigation regimes and plant spacing on bulb yield of two onion (Allium cepa L.) genotypes, an experiment was conducted at Kabootar Abad Research Station of Isfahan during two growing seasons (2005 and 2006). The experiment design was split-factorial with a ...
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Abstract
In order to study the effects of irrigation regimes and plant spacing on bulb yield of two onion (Allium cepa L.) genotypes, an experiment was conducted at Kabootar Abad Research Station of Isfahan during two growing seasons (2005 and 2006). The experiment design was split-factorial with a randomized complete block arrangement with four replications. Main plots included three irrigation regimes (irrigation after T1= 503 mm, T2= 703 mm and T3= 903 mm evaporation from class A pan). Sub-plots formed from factorial combination of two spring onion genotypes (Yellow Sweet Spanish and Dorcheh-Isfahan) with three plant spacing in rows (5, 7.5 and 10 cm). The results showed that total yield, marketable yield, bulb diameter and bulb height decreased as irrigation frequency increased. The highest total yield (6.867 kg/m2) and marketable yield (5.761 kg/m2) were produced in T1 treatment. Regarding total yield, the response of genotypes to increasing irrigation frequency was different. The Yellow Sweet Spanish genotype tolerated water deficit more than Dorcheh. Total yield, marketable yield and bulb height in Yellow Sweet Spanish genotype were significantly greater than Dorcheh, but diameter of bulb neck, dry matter and total soluble solids in Dorcheh were significantly greater than Yellow Sweet Spanish. Among the plant spacings, the 10 cm spacing had the lowest total and marketable yield and there were no significant differences between 5 and 7.5 cm spacing. But bulb size (height and diameter) increased as plant spacing increased.
Keywords: Onion, Irrigation regime, Spring genotypes, Bulb yield.
