نشریه فیزیولوژی گیاهان زراعی
پیاپی 38 (تابستان 1397)

In order to study the yield of different cultivars of safflower in different plant densities, the present factorial experiment in randomized complete blocks design with three replications was carried out at research farm of Khuzestan Agricultural Sciences and Natural Resources University in 2016-17 cropping year. The experiment factors included four cultivars (Goldasht, Sofeh, Isfahan and Faraman) and four levels of plant densities (20, 30, 40 and 50 plant per square meter). The results of the experiment showed that plant increasing per unit area significantly decreased number of heads per plant, number of seeds per head, grain yield and oil yield per unit area in all cultivars. Density had not significant effect on one thousand seed weight. Goldasht and Faraman cultivars had the maximum one thousand seed weight than two other cultivars. The highest grain and oil yields were obtained at an average of 2253 and 680 kilogram per hectare, respectively, at a density of 30 plants per square meter and from Sofeh cultivar. However, in this density, grain yield with density of 40 plants did not show any significant difference. Increasing density, number of heads per plant and number of seeds per head, respectively 37 and 22 percent and grain and oil yields decreased by 14 and 30 percent, respectively. Generally, the results showed that the number of heads per plant and the number of seeds per head were the most important components of grain and oil yields. According to the obtained results, Sofa and Isfahan cultivars with a density of 30 plants per square meter can be recommended for safflower cultivation in Khuzestan.

In order to investigate the effect of micronutrients elements application on qualitative and quantitative yield of rapeseed in drought tension conditions,the present research was conducted in Hamidieh in 2017-18 as split plots in a randomized complete blocks design with four replications. The experimental treatments included drought tension in two levels of optimal irrigation, irrigation cut off at the slaughter stage in the main plots and foliar application of complete fertilization of micronutrient in four levels including non-foliar application (control), and foliar application with two concentrations two in one thousand, four in one thousand liters, six in one thousand (cc in liters) were in sub plots. The results showed that the effect of drought tension and foliar application of micronutrient elements was significant on grain yield, seed number per pod, one-thousand seed weight, oil percentage and oil yield. The highest grain yield in optimal irrigation treatment (with an avearge of 3110.7 kilogram per hectare) and the lowest grain yield (with an average of 2280.22 kilogram per hectare) was allocated to irrigation cut treatment at slaughter stage. The results showed that with increase in the levels of micronutrient elements foliar application; grain yield, oil percentage and oil yield increased. Most of these traits were obtained from optimal irrigation and spraying of six per thousand, which did not have significant difference with treatment of four per thousand. The most grain yield (with an average of 3290.4 kilogram per hectare) was obtained in optimum irrigation treatment and foliar application of four per one thousand. In general, it can be stated that in order to achieve the maximum quantitative and qualitative yield in arid and semi-arid soils, irrigation should be done at all stages of growth, especially in the reproductive stage, so rapeseed can be planted or foliar application of micronutrient elements at four per one thousand is recomended.

In order to investigate the response of yield, yield components and seed quality of safflower cultivars to water deficit tension and seed priming with salicylic acid, an experiment was conducted as split plot factorial arrangement based on a randomized complete blocks design with three replications for two years (2015-16) at Shahroud Agricultural Research Center. The main plot consisted of three levels of irrigation based on the evaporation rate of a class A evaporation pan including: no water deficit tension (60 millimeter evaporation), mild water deficit tension (120 millimeter evaporation) and severe water deficit tension (180 millimeter evaporation) as well as subplot a combination of two factors: safflower cultivars (Goldasht, Sina and Soffeh) and seed priming (seeds treated with salicylic acid and non-treated seeds). The results of combined analysis showed that water deficit tension reduced significantly the investigated traits of safflower cultivars compared to non-water deficit tension, so that the severe water deficit tension caused reduction of plant height (15 percent), grain yield (29 percent), number of heads per plant (21 percent), number of seeds per heads (22 percent), head weight (17 percent), kernel percentage (5 percent), oil seed percentage (4 percent), oil yield (36 percent) and total chlorophyll (32percent) and increasing the percentage of seed protein (4 percent)and carotenoid content (17 percent) in comparison to non-tension conditions. The results of combined analysis showed the improvement of the investigated traits in primed treatment compared to control seeds, in both water deficit tension and non-tension conditions. The interaction of year with irrigation and cultivar had a significant effect on grain yield and oil yield, so that the highest grain yield from Goldasht cultivar and the highest oil yield from Soffeh cultivar were obtained under non-tension conditions.

In order to investigate some physiological characteristics and seed yield of canola cultivars under irrigation cut and different sowing dates, an experiment carried out as factorial split plot based on randomized complete blocks design with three replications at the research farm of Karaj Seed and Plant Improvement Institute during 2013-2014 and 2014-2015 cropping years. In the present experiment the sowing dates (October 7 and November 1) and irrigation cut (normal irrigation (control) and cut off irrigation from the pod formation stage to the next) as the main plots and 6 cultivars of canola included: SW102, HW1, HW2, BAL1, BAL4 and OKAPI (control cultivar) were assigned as subplots. The measured traits included chlorophyll content a, b and total, temperature of canopy, stomatal resistance, relative water content of leaf, biological and seed yield. The results indicated that the highest relative water content of leaf was related to SW102 cultivar and planting date of 7th October (91.64 moisture percent), under normal irrigation (88.87 percent moisture) and the lowest relative water content of leaf was related to planting date of 1st November and drought tension (78.59 percent moisture) for all cultivars indicated that drought resistance was high for all studied cultivars. The highest grain yield was related to two cultivars SW102 and HW1 by amount of 3876.9 and 3801.1 kilogram per hectare and planting date 7th October under normal irrigation (5060 kilogram per hectare). Considering the amount of seed yield on sowing date 1st November and normal irrigation 3114 kilogram per hectare and on sowing date 7th October and drought tension, was 3929 kilogram per hectare; as a result, we state that, the planting date was more important than the irrigation factor in our experiment in cold mild climates conditions.

In order to study of salinity tension and seed inoculation with plant growth promoting bacteria on antioxidant enzymes activity, chlorophyll content and leaf area index of Rye, a factorial experiment was conducted based on randomized complete blocks design with three replications at research greenhouse of Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2016. Factors under studied were salinity in four levels including non-application of salinity as control, salinity 25, 50 and 75 milliMolar by NaCl and seed inoculation by plant growth promoting bacteria in four levels including no inoculation as control, seed inoculation by Pseudomonas, Azosprilium and co-application Azosprilium and Pseudomonas. The results indicated that the highest antioxidant enzymes activity (such as catalase, peroxidase and polyphenol oxidase) were obtained in salinity of 75 milliMolar and co-inoculation seed with Azosprilium and Pseudomonas, and the least of them were obtained in non-application of salinity and no seed inoculation with plant growth promoting bacteria. With increasing soil salinity, chlorophyll content of a, b, total chlorophyll and leaf area index decreased and they were vice versa in seed inoculation with growth promoting bacteria. Maximum ratio of Sodium in root and shoots was obtained at the highest level of salinity and no inoculation seed with growth promoters’ bacteria and minimum in the lowest level of salinity and seed inoculation with Azosprilium and Pseudomonas. It seems that the co-application of growth stimulant bacteria can be used as a suitable means to reduce sodium in root and shoot, and increase leaf area index, chlorophyll a, b and total chlorophyll content of Rye under salinity tension.

Soil fertilization plays an important role in absorbing nutrients by plant, which is the most important factor in soil fertility, increasing soil organic matter. In this regard, a factorial experiment was conducted in a randomized complete blocks design with three replications in the area around the city of Someh-Sara. Experimental factors included vermicompost consumption levels (without fertilizers 5 and 10 tons per hectare) and the use of plant growth promoting bacteria (non-inoculation, Azotobacter and Azospirilum) for seed inoculation. The results showed that the interaction of vermicompost and bacteria on the amount of leaf chlorophyll, number of tillers, plant length, number of full grain per spike, biological yield and rice yield were significant at one percent probability level. The maximum rice yield was obtained from treatment of 10 tons per hectare of vermicompost + azosporillum with an average of 7096 kilogram per hectare; which was increased by 31.28 percent compared to control treatment and by the amount of 27.47 percent of 10 tons per hectare vermicompost application + non-inoculation treatment. Also, the maximum concentration of phosphorus and potassium grain was obtained from treatment of 10 tons per hectare of vermicompost + azosperplum, while the highest grain nitrogen concentration was observed from treatment with 5 tons per hectare of vermicompost + azotobacter. Therefore, according to the results obtained for the maximum yield of rice, application of 10 ton per hectare vermicompost is recommended with seed inoculation with Azospyrilum.

In order to investigate the physiological response of corn seedlings to non-threshold temperatures under different salicylic acid concentrations, a factorial experiment was carried out in a completely randomized design with three replications was carried out (controlled chamber growth conditions) at Kurdistan University Physiology Laboratory in 2013. The first factor was five levels of temperature (25, 30, 35, 40 and 45 Celsius degree) and the second factor was the four levels of salicylic acid foliar application (zero, 1.5, 2.5 and 5 mille Molar). The results indicated a significant effect of salicylic acid, temperature (P<0.01) and interaction of these two factors on photosynthetic capacity (dry weight and leaf area, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll) and biological traits (ionic leakage leaf and proline). The relative water content of the leaf was not subjected to temperature interaction with salicylic acid. By increasing salicylic acid concentration, the relative water content of the leaf increased and by increasing temperature decreased. Based on the interaction results, under higher temperatures than 35 Celsius degree (40 and 45 in Celsius degree), the photosynthetic capacity and relative water content decreased, and the ionic leakage and proline increased. The results also showed that, at temperatures up to 35 Celsius degree, salicylic acid concentration increased to five mille Molar and under temperatures 40 and 45 Celsius degree until 2.5 Mille Molar improves leaf area, photosynthetic pigments and increases proline. According to the general results under the temperatures the tolerance threshold, the corn seedlings suffered severe tension and salicylic acid to some degree moderated the thermal tension to a concentration of 2.5 mille Molar.

The phosphorus plays an important role in the growth and development of rapeseed. However, in a short period of time, two thirds of the phosphate fertilizer used is stabilized inaccessible in soil. Therefore, the only way to use phosphate accumulated in the lands is the use of phosphate biologic fertilizers. The present experiment was carried out in factorial in randomized complete blocks design with three replications in 2010 and 2011. Treatments including five bacteria of Pseudomonas (Pseudomonas fluorescence 1 (PSf1), Pseudomonas fluorescence 2 (PSf2), Pseudomonas putida 1 (PSp1), Pseudomonas putida 2 (PSp2) and not using bacteria (PS0)) and four levels of phosphorus fertilizer triple superphosphate (without fertilizer, 100, 150 and 200 kilogram per hectare) and two rapeseed cultivars, Hayola401 and SariGol. The results showed that the effect of different levels of phosphate solubilizing bacterial treatments on seed yield, biological yield, one thousand-seed weight, leaf and seed phosphorus content was significant at one percent level. The effect of different levels of phosphorus fertilizer on seed yield, biological yield, one thousand-seed weight, leaf and seed phosphorus content at one percent statistical level and on the number of pod per plant were significant at five percent level. The interaction of using phosphorus fertilizer and phosphate solubilizing bacteria on seed yield, leaf and seed phosphorus content was significant at one percent probability level. Comparison of averages showed that the use of phosphate solubilizing bacteria, especially Pseudomonas putida 2 (PSp2) can reduce the consumption of phosphorus fertilizer by 25 percent, thereby reducing production costs and environmental hazards.