The effect of cytokinin on growth indicators and photosynthesis of Cucurbita maxima L. under different levels of drought

Drought is one of the environmental stresses that have been recognized as the most important limiting factor for plant growth and production in most parts of the world. The aim of this study was to investigate the effects of drought on morpho-physiological indicators of Cucurbita maxima L. in two forms independently and with spraying Kinetin at two concentrations on growth parameters, photosynthetic pigments, and soluble sugars in leaves and roots. To achieve this aim, a pot experiment in a natural environment based on a factorial randomized complete block design was carried out in the form of 9 treatments with four replications. Three levels of drought stress in vegetative phase consisting of 2/3 and 1/3 of field capacity equivalent to mild and severe drought stress were applied with two concentrations of Kinetin including 2 and 4 mg per liter in the form of shoot spraying. The results showed that drought stress reduced the growth parameters, photosynthetic pigments, and starch and application of kinetin increased them significantly. On the other hand, drought stress increased soluble sugars while kinetin application decreased them. Overall results showed that the use of Kinetin in this study could significantly reduce the negative effects of drought on Cucurbita maxima L.