نساء قره باغلی

With the aim of evaluating the effect of salicylic acid in improving the efficiency of the aged pumpkin seeds under drought stress conditions, a factorial experiment was carried out in the form of a completely randomized design with three replications. Pretreatment of different concentrations of salicylic acid including zero (pretreated with water), 1 and 1.5 mM at different drought levels of zero, -0.2, -0.4 and -0.6 MPa were investigated. Indicators of mean germination time, germination percentage, seedling length, seed vigor, membrane electrolyte leakage, soluble carbohydrates, soluble proteins, malondialdehyde, ascorbate peroxidase activity, superoxide dismutase and catalase enzymes were evaluated. The results showed that the pretreatment of seeds with different concentrations of salicylic acid prevented the significant decrease in the germination indices of the deteriorated pumpkin seeds under drought stress. So that at the potential of -0.6 MPa, the treatment of seeds with 1.5 mM salicylic acid increased the percentage of germination, seed germination index, soluble carbohydrates and soluble proteins respectively 80.2, 169.4, 51.6, 93.4% and for the activity of ascorbate peroxidase, superoxide dismutase and catalase enzymes, 41.2%, 12% and 11.8%, respectively, compared to the control. Based on the research findings, pretreatment of salicylic acid (1.5 mM) is recommended in order to reduce the oxidative stress caused by drought for pumpkin.

In order to study the effect of salinity stress and different concentrations of lead under the influence of stress ameliorator, a factorial experiment was carried out in a completely randomized design with three replications. The experiment consisted of salinity stress at three levels (0, 25 and 75 mM of sodium chloride), lead in three concentrations (0, 10-5, 10-3 M of Lead nitrate) and stress ameliorators included 0 and 5 mg/L sodium selenate and 200 μm sodium hydrogen sulfide. The results showed that salinity and lead caused a significant reduction in root and shoot dry weight, absorption of potassium and zinc in root and shoot. Different concentrations of Lead had different effects on the studied traits. At 10-5 M of lead nitrate was observed, the reduction in absorption of lead and as a result improvement in root and shoot dry weight than without salinity. Whereas, application of selenium and hydrogen sulfide significantly improved the growth traits of garlic under salinity stress and Lead. Application of 5 mg/L sodium selenate and 200 μm sodium hydrogen sulfide cause reduce in the accumulation Pb in garlic seedlings and this is followed by an improvement in the content of the elements and as a result, growth increased under salinity stress and lead concentration especially at 10-5 Pb However, in the concentration of lead 10-3M, this effect was not observed. It is worth noting that in the present experiment, the positive effect of selenium on sodium hydrogen sulfide was more pronounced.

Selenium and hydrogen sulfide can alleviate the adverse effects of oxidative stress on plants by improving the oxidative defense system. In order to improve the oxidative defense system of garlic under lead and salinity stress by selenium and hydrogen sulfide, a factorial experiment was carried out using selenium and hydrogen sulfide in a completely randomized design with three replications. Experimental treatments included sodium chloride at three levels of zero, 25 and 75 mM, lead at three concentrations of zero, 10-5 and 10-3 M lead nitrate as well as stress ameliorators in three levels (5 mg / L sodium selenate, 200 μm sodium hydrogen sulfide and control). The results showed that with increasing salinity and lead concentration, a significant decrease in root length and dry weight was observed. In the treatment of 10-5 M lead under 75 mM salinity, the activity of antioxidant enzymes superoxide dismutase, ascorbate peroxidase and catalase were 4.44, 11.76 and 10.47%, respectively, and compared to the zero lead stress and 75 mM, salinity was improved with selenium application. In general, sodium selenate and sodium hydrogen sulfide decreased the uptake of lead in root tissue whereas increased the length and dry weight of roots under salinity stress at a concentration of 10-5 M, but at a concentration of 10-3 M lead, this effect was not observed. Overall results showed that the positive effect of selenium on hydrogen sulfide during salinity stress was more evident in reducing the negative effects of lead. It seemed that selenium suppressant improved the growth parameters of garlic roots under salinity stress and low lead concentrations by reducing lead absorption and increasing the activity of antioxidant enzymes.

IntroductionSalinity is one of the most important factors reducing the yield of many crops. The usual response of plants to increasing concentrations of salt at the root zone is osmotic stress, ionic toxicity and nutrient deficiencies. Also, cadmium is one of the major heavy metal pollutants by high toxicity and accumulation, caused retard in the plant growth.The problem of Cd toxicity becomes even more severe when plants are exposed to salinity. The different materials are considered to mitigate the negative effects of stress on plants. In this regard, the selenium introduced as one of the trace elements beneficial to plants so that it can protect plants against adverse effects of stress. The purpose of this study was to determine uptake of cadmium, sodium, potassium and developmental and physiological changes of garlic seedlings exposed to cadmium under salt stress in the presence of selenium.
Materials and methodsA factorial experiment in based on a completely randomized design with three replications was done in Crop Physiology Laboratory, Faculty of Agriculture, Bu Ali-Sina University. Cadmium as cadmium chloride in 0, 10-4, 10-3 and 10-2 M concentrations and sodium chloride at two levels (0 and 25 mM) and sodium selenate (0 and 5 mg/ l , Na2Se2O4) were added to the growth medium. The traits growth of root and shoot dry weight was measured. In order to determine the content of cadmium, sodium and potassium, 0.2 g of tissue dry matter ground and by the wet digestion method and atomic absorption spectrophotometer (Varian, 220) was read content elements. The amount of chlorophyll in the shoot was calculated using Arnon method. Parameters of net photosynthesis, stomatal conductance and transpiration were measured in a fully open mature leaf by using an infrared analyzer. Data analysis was performed using SAS software and mean comparisons test data was used by least significant difference (LSD) and LSMEANS.
Results and discussionThe results showed that salinity and cadmium have caused a significant reduction in root and shoot dry weight, total chlorophyll content, net photosynthesis, stomatal conductance and transpiration. Interaction between salinity and Cd at 10-4 M decreased the absorption of Cd in seedling and followed by more improving chlorophyll content, net photosynthetic as a result from root and shoot dry weight increased compared to non-saline condition. But this effect was not observed at 10-3 and 10-2M Cd concentrations. On the other hand, selenium alone or in the presence of salinity or cadmium caused a significant increase in above mentioned growth traits. Also, salinity and cadmium raised sodium to potassium ratio in the shoot. The interaction of between salinity and cadmium with increasing concentration of Cd, sodium to potassium ratio enhanced in the aerial parts of the plant.
ConclusionsOverall, salinity and cadmium stresses in garlic seedling media, reduced root and shoot dry weight, chlorophyll, photosynthesis, transpiration and stomatal conductance. Application of selenium alone and also in present salinity and cadmium caused a significant increase in root and shoot dry weight, chlorophyll, net photosynthesis, transpiration and stomatal conductance. Although low concentrations of salinity and cadmium (10-4M) revealed a significant increase in root and shoot dry weight, which implies an increase in chlorophyll content and photosynthesis in plant garlic. Selenium also improved the total chlorophyll, photosynthesis in the interaction between salinity and cadmium. This subject confirms the positive effect of selenium on garlic seedling growth under cadmium and salt stresses, which in subsequent studies the physiological and molecular processes should be further investigated.

In order to study the effect of zinc sulfate and iron sulfate under drought stress on yield and kaempferol in chicory (Cichorium intybus L.), a field experiment was conducted at Bu-Ali Sina university in 2012 growing season. The experiment was carried out as split plot based on complete randomized block design with three replications. Drought stress in three irrigation levels at 60 (Control), 90 (mild stress) and 120 (severe stress) mm from evaporation pan class A were assigned to main plot and four foliar application (Fe, Zn, Fe Zn and control) treatment were randomized in sub-plots. Results showed that drought stress in 90 and 120 mm caused reduction about 70.52 and 111.51 Kg/h in seed yield, 1280.71 and 1811.96 Kg/h in biological yield, 121.03 and 293.54 Kg/h in leaf yield compared to the control, respectively. Drought stress also increased kaempferol percentage in 90 and 120 mm irrigation regime about 38 % copmpared to 60 mm irrigation regim. Foliar spray of zinc and iron had no significant effect on the percentage of leaf kaempferol. The number of lateral baranch and SPAD number in 90 mm irrigation regime and foliar application of Zn Fe increased about 9.4 compared to the control. Foliar application of zinc sulfate increased root yield and biological yield about 70.43 and 314.5 Kg/h, respectively. The number of lateral branch and biological yield in 120 mm irrigation regime and application of zinc and iron at the same time increased about 529 Kg/h. Foliar application of Zinc sulfate also increased root yield about 37.5 Kg/h compared to the control.