foliar application of salicylic acid, methyl jasmonate and potassium sulfate on photosynthetic characteristics and fruit quality of pomegranate

the present research designed to evaluate the effects of foliar application of methyl jasmonate (meja), salicylic acid (sa) and potassium sulfate on improving fruit quality and photosynthesis system. ten treatments include: sa (0.3, 0.6 and 0.9 mm), meja (0.5, 1 and 2 mm), potassium sulfate (0.5, 1 and 1.5%) and distilled water (control) were sprayed on pomegranate trees 2 and 7 weeks after full bloom early in the morning. results indicated that sa, meja and potassium sulfate increased phenolic compound and 1.5% of potassium sulfate and 0.5 mm of meja significantly increased the antioxidant activity of pomegranate fruit. application of sa at 0.6 mm increased significantly hue angle of fruit peel. foliar application of potassium significantly increased fv/fm and pi parameter. furthermore, total chlorophyll, b chlorophyll and cartenoids increased by 0.5 % of potassium sulfate, however,  the differences were not significant. besides, 1% and 1.5% of potassium sulfate significantly increased the ph of fruit juice.