Effects of Fulvic Acid and Putrescine on the Morpho-Physiological, Biochemical Characteristics and Nutrients Uptake in Grapevine (Vitis Vinifera L.) Cv. Shahani Exposed to Alkaline Soil Conditions

Alkaline stress is one of the major environmental factors that limit plant growth and development and crop production. In order to investigate the effect of fulvic acid and putrescine on some morphophysiological, biochemical characteristics, and nutrient uptake of Shahani grapevines cultivar under alkaline soil conditions, a factorial experiment was conducted in a completely randomized design with two factors including four concentrations of fulvic acid (0, 100, 200, and 300 mg L-1 as soil application) and four concentrations of putrescine (0, 1, 2, and 4 mM as foliar spray) in four replications and under greenhouse conditions. Alkaline soil had a negative effect on the vegetative characteristics of Shahani grapevines cultivar. The highest shoot fresh weight was observed treating of 200 mg L-1 fulvic acid along with 2, and 4 mM putrescine treatments. The highest root fresh weight was obtained at concentrations of 300 mg L-1 fulvic acid and  2 mM putrescine. The lowest amount of ion leakage was observed at the highest concentration of putrescine. The amount of soluble sugars increased by 23.4 and 23.4% , in 2, and 4 mM putrescine concentrations compared to the control, respectively. At the level of 300 mg L-1 fulvic acid and concentrations of 2, and 4 mM putrescine, the nitrogen content increased by 33.16 and 35.35%, compared to the control, respectively. Also, the levels of iron, copper and manganese also improved with increasing concentrations of fulvic acid and putrescine. The findings of this research confirm the positive role of fulvic acid and putrescine treatments in mitigating the harmful effects of alkaline stress on Shahani grapevines cultivar.