Ever-increasing shortage in global agricultural water sources urged the researchers to investigate sustainable strategies for alleviating the negative effects of drought on plants in semi arid or arid regions. In this sense, foliar fertilization gained particular significance as it supports the plant to cope with water shortage. This study was conducted to investigate the leaf physiological response of the grapevine ‘Narince’ to various organic leaf fertilizers. Leaf protein content was also determined to compare treatment effects on nutritional value of grape leaves since the leaves of this cultivar are consumed in various ways. Both stomatal conductance, leaf chlorophyll and protein content increased in response to leaf fertilizers in varying degrees according to the products used. To illustrate, Herbagreen pulverization resulted in the highest stomatal conductance (gs) (324.7 mmol H₂O m^-2 s^-1), and was followed by Cropset (323.5 mmol H₂O m^-2 s^-1) while the lowest gs value was obtained from control vines (295.4 mmol H₂O m^-2 s^-1). The highest chlorophyll and protein contents were obtained from ISR 2000 (32.9 mg kg^-1) and Maxicrop (21.5%) treatments, respectively. Leaf chlorophyll content had a significant positive correlation with leaf protein content when all the observations were pooled. Therefore, the organic leaf fertilizers can be considered as a safe, sustainable and innovative strategies to support plants to cope with drought.

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