فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 51 (پاییز 1398)

Application of mycorrhizal fungi may improve the nutritional status of the plant and increase its resistance to environmental stresses, such as deficiencies water. This research was conducted in a split plot experiment based on randomized complete block design with three replications at Hamidieh region of Ahvaz in 2018. Treatments consisted of irrigation regimes with three levels (60, 90 and 120 mm evaporation from class A pan evaporation) assigned to main plots and combined use of mycorrhiza and phosphate stabilizing bacteriawith four levels (non application, mycorrhiza, mycorrhiza and phosphate stabilizing bacteria and Phosphate solublizing bacteria) to sub plots. The results showed that the effects of irrigation regimes and combined use of mycorrhiza and phosphorus fertilizer on leaf area index, symbiosis percent, seed number of seeds per row of corn ear, number of seeds per ear, 1000 seed weight and seed yield were significant. Mean comparisons showed that combined treatment of mycorrhizal fungi and phosphate solubilizing bacteria resulted in the maximum number of seeds per ear, number of seeds per row, 1000 seed weight and leaf area index. The highest seed yield (6400.55 kg.ha-1) was obtained from 60 mm evaporation from class A evaporation pan and the combined application of mycorrhiza and phosphate solubilizing bacteria and lowest from 120 mm evaporation and without application of mycorrhiza and phosphate solubilizing bacteria. It can be concluded that combined use of mycorrhiza and phosphate solubilizing bacteria can be considered promising in growing maize for seed at this experimental region.

To investigate the effect of salicylic acid on photosynthetic system and seed yield in soybean genotypes under drought stress a factorial experiment was conducted in a completely randomized design in both greenhouse and laboratory of Mohaghegh Ardebili University in 2015. The factors consisted of water stress at 3 levels (85, 65 and 45% of field capacity), salicylic acid at 3 concentrations (0, 0.4 and 0.8 mM) and three soybean genotypes, Williams, D42X19, and L17. The results showed that the relative water content, stomatal conductance, chlorophyll a and b, chlorophyll a/b ratio, leaf area, maximum fluorescence and quantum yield decreased as the result to drought stress, while Williams showed more tolerance to drought stress as compared to other two genotypes. Application of 0.4 mM salicylic acid as compared to high concentration (0.8 mM) and control was the most effective treatment on reducing the adverse effects of drought stress. It could be said that this may increase the relative water and chlorophylls contents, leaf area, quantum yield and stomatal conductance under drought stress conditions. It seems that carotenoid contents as a result of drought stress and application of 0.8 mM salicylic acid were increased in soybean genotypes, especially in L17. SLA was also increased due to drought stress, which was higher in L17 genotype than other genotypes. According to the results of this study, williams genotype was the most tolerant to drought stress as compared to the other genotypes, and the application of salicylic acid would enhance tolerance to drought stress in soybean genotypes.

To Investigate the effect of super-adsorbent and irrigation levels on quantitative and qualitative characteristics Rastar cultivar of sugar beet a split plots experiment was conducted based on randomized complete block design with three replicas was conducted at the Agricultural University of Mahabad in 2017. Irrigation in three levels (Irrigation after 60, 120 and 180 mm evaporation from class A pan) is assigned to main plats and super-absorbents A200 in four levels (0, 50, 150 and 200 kg.ha-1) to the subplots. The simple effects of irrigation regime and superabsorbent on all traits, except for the coefficient of sugar extraction, was significant. The interaction of treatments were significant on the dry weight of shoot, sugar content, root yield, and sugar yield and white sugar yield. In this research, the highest leaf area index, root length, and leaf relative water content and the lowest amount of white sugar content belonged to irrigation after 60 mm evaporation. Application of 50 and 150 kg.ha-1 super-absorbent highly increased leaf area index, root length, and leaf relative water content while it decrease the percent of white sugar content. The highest shoot dry weight (3.97 t.ha-1), root yield (69.35 t.ha-1), sugar yield (10.51 t.ha-1) and white sugar yield (9.39 t.ha-1) and the lowest percentage of sugar (15.20%) caused by irrigation interval after 60 mm evaporation and using 200 kg.ha-1 super-absorbent. Interactions due to irrigation and use of super-absorbent showed that there was the non-significant difference between irrigation regime after 60 mm in control treatment (not applicable super-absorbent) with the application of 50, 150 and 200 kg.ha-1super-adsorbent in irrigation regime after 120 mm and application of 150 and 200 kg.ha-1super-absorbent in irrigation regime after 180 mm. Thus, using of 150 kg.ha-1 super-absorbent in irrigation regime after 180 mm evaporation can have similar white sugar yield as it was under irrigation regime after 60 mm in control treatment (not applicable super-absorbent) while saving about 8650 m3 per hectare by using this treatment.

In order to investigate the effects of water deficit stress and nano-TiO2 and salicylic acid foliar application on some biochemical traits of corn704 single crossplant, an experiment was conducted in split plot factorial based on RCBD in three replications at the Research Station of the Islamic Azad University, Tabriz Branch, during growing seasons of 2017-2018. Treatments were water deficit stress in three levels contained: 50, 75 and 100% filed capacity (FC) as well as thefactorial combination of nano-TiO2 (n-TiO2) foliar application in three levels contains: non application (control), 0.01 and 0.03 and salicylic acid (SA) foliar application in two levels contain: non application and 0.5%. Result showed that 0.5% SA foliar application under 50% water deficit stress had the highest peroxidase, polyphenol oxidase and lowest malondialdehyde activity. Furthmore, 0.01% n-TiO2 foliar application had the highest effect on peroxidase and lowest effect on malondialdehyde activity. Use and non-use condition of SA, 0.01% n-TiO2 foliar application had the positive effect on polyphenol oxidase activity. Foliar application of 0.01% n-TiO2 and0.5% SA under water deficit stress had the highest effect on soluble carbohydrates and proline. Based on the results, the guaiacol peroxidase enzyme activity increased with increasing water deficit stress level, so that the most activity of this enzyme was observed in irrigation with 50 % filed capacity. Considering the role of the traits studied in cooperation with each other in preventing the production of active oxygen species and reducing the effects of water deficit stress, SA and n-TiO2, increasing the activity of enzyme peroxidase, polyphenol oxidase, soluble carbohydrates, Proline and in contrast to the reduction of malondialdehyde reduced the negative effects of water deficit stress. Since SA and n-TiO2 had positive effects on the enzymes affecting plant physiology, the seed yield increased significantly compared to control and water deficiet conditions.

Determination of optimal plant density is one of the main factors that may affect crop growth and seed yield when planting is performed in the plant residues especially in conservation tillage systems. To investigate the effect of plant density on leaf gas exchange of wheat cultivars, a field split plot experiment based on randomized complete blocks design with three replications was carried out at Karaj Research Farm of Seed and Plant Improvement Institute in Iran. In this study, the main factor was three levels at plant densities (400, 500 and 600 seed per m2) assigned to main plots and five wheat cultivars (Sivand, Sirvan, Pishtaz, Pishgam and Parsi) to sub-plots. Results of analysis of variance showed that transpiration rate (E) (p<0.05), stomatal conductance (Gs) (p<0.01), net photosynthetic rate (Pn) (p<0.01) and Quantum yield (Qy) (p<0.01), number of grain per spike (GPS), seed weight (SW), seed yield (SY), biological yield (BY) and harvest index (HI) were affected by plant density and cultivar significantly. In addition, interaction effect of plant density×cultivar was significant on leaf temperature (LT) (p<0.01), intercellular CO2 concentration (Ci) (p<0.05) and biological yield (BY) (p<0.01). The results also indicated that increment of plant densities of 400 to 600 seed per m2 decreased E, Gs, Pn and Qy. Increasing plant density decreased GPS and HI. The Pishgam cultivar had the highest E and Gs, while higher values of Pn, Qy and water use efficiency belonged to Parsi cultivar. The highest value of SY was obtained from Sirvan cultivar.

To study the effect of sulphur and vermicompost application on morphological and agronomic traits of soybean (Hubbit Cultivar), an experiment was carried out at Aligudarz city, Lorestan province, Iran in 2017. The experimental design was two-factor split-plot design based on a randomized complete block design with three replications. Factors were vermicompost as the main factor with three levels (0, 4 and 8 ton.ha-1) and sulphur fertilizer as a sub-factor with three levels (0, 250 and 500 kg.ha-1). The results indicated that the main and interaction effects of vermicompost and sulphur on plant height, stem number per plant, pod length, number of pods per plant, 100 seed weight, protein yield, oil yield, grain yield, biological yield and soybean harvest index were significant. The highest plant height belonged to the application of 4 tons per hectare of vermicompost alomg with 250 kg.ha-1 sulphur fertilizer (76.52 cm) and the lowest to not using vermicompost and sulphur (control) (61.50 cm). The highest 100 seed weight, protein yield, oil yield, seed yield and harvest index were produced from 8 tons per hectare of vermicompost and 250 kg.ha-1 sulphur fertilizer respectively (20.86 g, 475.25 kg.ha-1, 787.58 kg.ha-1, 252.250 kg.ha-1, 34.13%) and their lowest values from application of fertilizers of vermicompost and sulphur (control) respectively (12.05 g, 443.26 kg.ha-1, 243.66 kg.ha-1, 1440.11 kg.ha-1, 31.44%, respectively). The results also showed that simultaneous use of vermicompost and sulphur fertilizers at levels of 8 tons and 250 kg.ha-1 was the best treatment for increasing soybean yield under experimental climatic conditions

Life cycle assessment is an appropriate method to study the environmental impacts of producing a crop plant throughout its production cycle. This research was conducted with the aim of evaluating the life cycle of irrigated wheat production under nitrogen amounts and splitting in Bushehr province during 2017-18The as split plots based on a randomized complete blocks design with four replications. Four nitrogen rates including 70, 140, 210 and 280 kg urea ha-1 was considered as main plots and three nitrogen splitting in basal, beginning of tillering, stem elongation and booting stages was chosen as sub plot.The results demonstrated that with increase of nitrogen application an amount of cumulative energy demand, cumulative energy demand, acidification, eutrophiction and malodorous air were decreased. The average amount of ecological footprint was 1125.87 m2 per year which CO2 emissions had shown the highest effect on the ecological footprint. The average amount of global warming potential (GWP) was 20a and GWP 500a were 400.53 and 384.30 kg CO2 eq, respectively. All pollutants released into the air and the water experienced a decreasing trend with increasing nitrogen rate. By group comparing between different levels of nitrogen at splitting levels, it can be stated that the main cause of variations in the amount of pollutants was the higher output (yield) compared to inputs. Indeed, nitrogen application in four developmental stages has resulted in maximum plant use, resulting in increased yield and emission reduction per unit area. Therefore, reducing the emission of pollutants by increasing nitrogen consumption can be due to yield increasing.

The present research was done to evaluate the response of seed and oil yields and its components of some rapeseed genotypes at saline areas of Tabriz plain and to select promising lines. The experiment was carried out at the Khosroshah Station of East Azarbaijan Agriculture and Natural Resources Research and Education Center with saline soil (EC of soil and water were 6.7 and 3.2 dS m-1 respectively), during cropping season of 2017-18. The experiment was conducted as randomized complete blocks design with 38 rapeseed genotypes and three replications. Among the genotypes under study significant differences were observed in plant height, seed yield and its components, oil percent, seed and oil yields. The results indicated that WRL-96-01 produced highest silique number per plant (123), seed number per silique (30.3), 1000 seeds weight (3.4 g), seed (3268 kg.ha-1) and oil (1526 kg.ha-1) yields respectively. Comnly used varieties in the area like Okapi and Nima produced lower seed and oil yields under this experiment conditions. Significant and positive correlations were seen among the seed yield and its components, oil yields and also between oil yield with oil percent and seed yield. These results indicate that genotyps under study produced proper seed and oil yields under saline condition. By cluster analysis with ward method, 20 genotypes with higher seed and oil yields, located in one group as promising lines. It seems that these genotypes could be used for future evaluation in saline areas of Tabriz plain and areas with similar climate.