نشریه فیزیولوژی گیاهان زراعی
پیاپی 25 (بهار 1394)

In order to investigate the impact of nitrogen fertilizer levels on some physiological traits of winter cereals¡ this experiment was carried out in Gonbad- e- Kavous research field as factorial based in randomized complete blocks design with four replications during 2013- 2014 cropping year. The first factor including bread wheat Koohdasht cultivar¡ durum wheat Seimareh cultivar¡ six rowed barley Sahra cultivar¡ two rowed barley Khoram cultivar¡ naked barley Line 17 cultivar¡ triticale Canadian cultivar and oat Javaniloo cultivar and the second factor nitrogen fertilizer evaluated at two levels zero and optimum. Results showed that nitrogen and cultivar interaction was not significant on these traits but cereals specious indicated significant difference in yield and yield components¡ biological yield¡ harvest index and grain rate and duration grain filling period at one percentage level. Triticale reached to physiological maturity stage with 1885.85 growth degree days by 160 days after planting. Triticale reached to physiological maturity with receiving 1885.85 growth degree days by 160 days after planting and was allocated the highest number of spike per square meter¡ biological yield¡ grain yield and harvest index. Oat with receiving 2069.66 growth degree days by 167.1 days after planting showed the lowest one thousand -grain weight¡ grain yield and harvest index rather than other cereals. Spike number per plant¡ grain number per spike¡ grain weight and duration filling period had significant and positive correlation with economic yield and spike number per plant had the most significant correlation with grain yield. Biological yield and harvest index showed significant and positive correlation to grain yield either.

In order to investigate the effect of water deficiency tension and consumption of absorbent substances such as animal manure¡ zeolite and bentonite¡ this experiment was carried out in educational-research field of Arak Islamic Azad University in 2010-2011 cropping year. The experiment was conducted as split-plot arrangement in a randomized complete blocks design with three replications. The experiment factors consisted of irrigation in three levels (100¡ 85 and 70 percentage plant required water) in the main plots and absorbent materials at six levels (control¡ 30 ton per hectare manure¡ 15 ton per hectare manure using four ton per hectare zeolite¡ 15 ton per hectare manure using two ton per hectare bentonite¡ using four ton per hectare zeolite using two ton per hectare bentonite¡ 15 ton per hectare manure using four ton per hectare zeolite using two ton per hectare bentonite) in sub plots. Results showed that the effect of water tension was significant on the traits such as water use efficiency and leaf water content at one percent level and peduncle length at five percent level. Using absorbent materials had significant effect on cell ion leakage and total biomass at one percent level. Between the levels of water tension¡ irrigation treatment based on 70 percent plant required water with an average 6968 µs cm-1 and control irrigation treatment with an average 6208 µs cm-1 were allocated the highest and lowest amount of cell ion leakage respectively.

In order to investigate lines canola germination indices under drought tension conditions this experiment as factorial in a completely randomized design with four replications was conducted in 2013. Promising lines in twelve levels BAL1, BAL2, BAL3, BAL6, BAL8, BAL9, BAL11, BAL15, L72, L109, R15 and Okapi and drought tension in three levels zero, -4 and -8 bar with a solution of PEG 6000 as first and second factors were considered. The maximum percentage of germination was related to line L109 and non-tension conditions by 99 percentage, also line L109 in drought tension -4 had germination and daily germination rate higher than standard, as well seed vigor index decreased significantly with increasing severity of drought tension. Results showed that the maximum length of the root by 5.2 cm compared with the control of drought tension -4 and L109 line. So, according to the direct relationship of increasing mean germination with the root length, highest average germination compared to the control was reported 11/14 cm for L109 line. Those seeds which are able to have acceptable germination in drought tension conditions, in arid and semi-arid regions, will have great value because they are more likely to move from this stage.

In order to investigate the effect of different planting densities on growth, yield and yield components of two lines of promising soybean cultivation in the summer planting in Gorgan region this experiment was carried out in Gorgan Agricultural Research Station in 2012 (Iraqi area) as factorial arrangement in randomized complete blocks design with three replications. The first factor including plant density at six levels (10, 14, 18, 22, 26 and 30 plants per square meter) and the second factor was two late lines of soya (WE6 and PE10). The results showed that the effect of density on plant height, number of branches, number of pods per plant, harvest index, one thousand-grain weight, grain yield was significant at one percentage probability level. But for other traits became non-significant. Interaction density at line on plant height, harvest index, number of pods, one thousand-seed weight, and grain yield was significant at one percentage probability level. The highest one thousand- grain weight and grain yield was related to the density of 26 plants and the lowest to the density of 10 plants in one square meter. Maximum harvest index, number of pod, one thousand-grain weight was related to line WE6 and the lowest to the PE10. Among the densities, the density of 26 plants per square meter with 2177 kilogram per hectare was allocated the highest grain yield. Generally, with increasing density the amount of yield of two tested lines increased, but line WE6 at density of 26 plants per square meter with 1940 kilogram of seeds per hectare showed superiority.

According to limited availability of water for crops production, fining genotypes with optimal efficiency of water use is among the research priorities. For this purpose this research was conducted in order to investigate the effect of water deficiency tension on photosynthesis indices and finally production and forage yield of three sorghum genotypes as factorial in a completely randomized design in University of Mohaghegh Ardabili research greenhouse in 2013. The experiment treatments consisted of water deficiency tension at four levels (80, 65, 45 and 25% of field capacity) and three genotypes of sorghum (KFS17, KFS6 and KFS2). The results showed that the main effect of water deficit tension and genotype had significant difference in most measured traits at one percentage probability level. Interaction between water deficit tension and sorghum genotype was significant only on the amount of chlorophyll a, carotenoids, chlorophyll stability and forage yield. So that the deficit water tension caused decreasing of chlorophyll a, b, total chlorophyll, maximal fluorescence (Fm), quantum yield of photo system II (Fv/Fm) and forage yield and caused increasing in chlorophyll a to b ratio, carotenoids, chlorophyll stability, Fo (minimal fluorescence in dark adapted conditions), Ft (fluorescence intensity or instantaneous). Although KFS6 genotype had the highest value in many of the measured traits, however, the highest yield was belonged to KFS2 genotype and then KFS17. Also based on regression analysis the KFS17 genotype showed the highest correlation between chlorophyll a, total chlorophyll and carotenoid amounts with the yield. Generally, yield reduction in KFS2 genotype can be related to consume more plant photosynthesis materials in order to withstand against the tension.

Salicylic acid is involved in the regulation of different physiological processes and growth and development of plant. In present research, effect of salicylic acid on some morphological and physiological characteristics of soybean under drought tension conditions was investigated as factorial experiment in a completely randomized statistical design with three replications. Soybean seeds were planted in pots containing fertilized soil and after four-leaf stage they were exposed by different treatments of dryness tension (zero, 25, 50 and 75 percentage of water need ratio) and Salicylic acid spray (zero, 0.5, 1 and 2 mM). The obtained results showed that effect of drought tension on all of measured parameters was significant except shoot soluble sugar. Also, interaction of drought tension and Salicylic acid, on all measured traits was statistically significant except shoot length, chlorophyll a content, b and carotenoid and peroxides enzyme activity. Salicylic acid of 1 and 2 mM concentrations improved the measured traits of plants at 75 percentage drought tension conditions.

In order to investigate the effect of plant growth regulatory of paclobutrazol on the amount of redistribution of assimilates to the grain of three cultivars of wheat under favorable and terminal heat tension conditions two independent experiments were conducted as split plots in a randomized complete blocks design and with four replications in Dezful area in 2013-2014 cropping year. The first experiment ncluding the cultivation of wheat cultivars (Star, VeerNac and Chamran) in recommended date (November) and in order to coincide phenological stages of plant growth with terminal heat tension after pollination, planting date in another experiment was considered on the first of February. In each experiment, four levels of paclobutrazol included zero, 50, 100 and 150 mg per liter as main plots and three cultivars of bread wheat included Star, VeerNac and Chamran were considered as sub plots. Results showed that paclobutrazol consumption significantly increased the amount of redistribution of food storage and current photosynthesis of wheat cultivars in both favorable and terminal heat tension conditions. Heat tension, reduced the amount of redistribution and the amount of current photosynthesis about 12 and 31 percentage, respectively. Average share of the redistribution of wheat cultivars in heat tension conditions compared to favorable conditions, 17 percentage increased. The highest and lowest amount of share of the redistribution in heat tension conditions compared to favorable conditions was dedicated to the late maturity cultivar Star and earlymaturity VeerNac, respectively. In this research, the positive effect of using paclobutrazol on the gradient of the changes the amount of grain yield in terminal heat conditions was more than favorable conditions, so that the average increase in grain yield of paclobutrazol applying treatments in studied cultivars of wheat compared to the control treatment (non-use of paclobutrazol), in favorable conditions, was about 17 percentage and in season terminal heat tension conditions, about 23 percentage.

Deficit water is one of the most important factors of reducing crop growth and yield that due to reduction of water resources, the intensity of this phenomenon increases more and more. However, by adopting managements such as selecting the suitable treatment and applying the stimulating generator of tolerance to Deficit water in plants, the effect of Deficit water in plants can be reduced. This experiment was conducted in order to study the effect of different levels of irrigation(irrigation after 70, 130 and 180 mm evaporation from the evaporation pan) and applying potassium humate (control, 10 and 50 per one thousand potassium humate) on two hybrids 604 and 704 in three replications and as split plot. The results of the present study indicated that the reduction in irrigation water, reduced seed yield significantly. As irrigation levels after 130 and 180 mm evaporation from the evaporation pan reduced 23.6 and 49.6 percent of seed yield compared to the irrigation level after 70 mm evaporation from the evaporation pan. Irrigation levels caused a significant reduction in seed number in maize and one hundred-seed weight. Using potassium humate had no significant effect on seed yield, but treatment of 50 per thousand of potassium humate caused a significant increase in the leaf biomass and leaf area. It seems that in the studied hybrids, the reduction in the irrigation water reduces seed yield and the use of potassium humate had no effect on the economic performance of studied hybrids of corn.