Effects of foliar spraying kinetin on growth parameters and photosynthesis of tomato under different levels of drought stress

The effects of 2 concentrations of kinetin, i.e., 2 and 4 mM together with 2 levels of drought stress, i.e., moderate (35% soil saturation capacity) and severe (20% soil saturation capacity) were investigated on the growth parameters of tomato including fresh and dry leaf weight, leaf number, leaf surface area, fruit number, fruit weight, and enzymatic antioxidants. To this end, first tomato plants cultivar super strain were planted in pot culture. During the early growth stage, the plants were subjected to 2 drought stress levels (35% and 20%) as well as normal irrigation (control: 50% soil saturation capacity). Also the plants were treated with foliar spraying of kinetin for 60 days. There were a total of 9 treatments in the experimental study based on a completely randomized design with 4 repetitions. The finding suggested that spraying kinetin at both levels of moderate and severe drought stress improved growth parameters in tomato. While soluble sugars increased under drought stress, the insoluble sugars content decreased. Application of kinetin on the other hand reduced soluble sugars and increased insoluble sugars content under various levels of drought stress. Finally, chlorophyll a and b contents were reduced under drought and kinetin application had no significant effect on plant pigments.