Effect of foliar application of salicylic acid and micronutrients on photosynthetic activities and rapeseed grain yield under water deficit tension

In order to investigate the effect of foliar application of salicylic acid and micronutrients on photosynthetic activities and grain yield of rapeseed under low water tension conditions, an experiment was conducted as a factorial split plot in the form of a statistical randomized complete blocks design with three replications in Agricultural University of Lorestan in the cropping year of 2016-2017. Irrigation at two levels of 20 and 70 percent of field capacity depletion in the main plots and the composition of micronutrients (B1 non-consumption and B2 foliar application at a ratio of 2 per thousand) and salicylic acid factor (concentrations of zero, 0.5, 1 and 1.5 milimolar) were studied in subplots. The results showed that the triple interaction on leaf area index, stomatal conductance, transpiration rate and grain yield were significant. The highest grain yield of 4424 kilogram per hectare was obtained under non-tension  and foliar application of micronutrient fertilizer with a concentration of 1.5 milimolar salicylic acid. Water deficit tension affected plant leaf area index and plant gas exchange and by reducing physiological traits such as photosynthesis rate, stomatal conductance, mesophilic conductance, transpiration rate and increasing the concentration of carbon dioxide under the stomatal chamber finally reduced grain yield in canola; however, foliar application of salicylic acid and micronutrients, while significantly reducing the concentration of carbon dioxide under the stomatal chamber, significantly increased leaf area index, mesophilic conductance, stomatal conductance, transpiration rate and photosynthesis rate. Transpiration rate and photosynthesis rate to some extent reduced the negative effects of drought tension on physiological traits of rapeseed and increased grain yield by 37.79 percent. Therefore, Ferti ‌ triple mix micronutrient (iron + zinc + manganese) with a concentration of 2 per thousand along with a concentration of one and a half millimoles of salicylic acid is recommended to reduce the adverse effects of water deficit tension and achieve proper performance.