The effect of kaolin on drought stress tolerance and some physiological responses of bell pepper (Capsicum annuum L.)

Drought stress is considered to be an important abiotic constraint, limiting plant growth and productivity worldwide. The aim of the present experiment was to investigate the effects of exogenous application of kaolin on growth, yield and physiological responses of sweet pepper plants under drought stress. The experiment was conducted in a factorial experiment based on randomized complete block design in three replicates at the Faculty of Agriculture of Ilam University in 2019. The first factor included three concentrations of kaolin (0, 2.5 and 5%) and the second factor included three irrigation intervals (2, 4 and 6 days).The results showed that total yield, growth parameters and chlorophyll content decreased while proline, Malondialdehyde and antioxidant enzymes activities increased with increasing level of water stress. Kaolin treatment improved growth parameters, total yield and chlorophyll content of pepper plant subjected to drought stress and provided significant protection against drought stress. Moreover, kaolin decreased the malondialdehyde accumulation, which was correlated with the increased activities of antioxidant enzymes. In general, the results indicate that foliar application of kaolin (especially 2.5%), could be effectively used to protect pepper’s plants from the adverse effects of drought stress.