Flooding or drought which one is more offensive on pepper physiology and growth?

Both extreme usage of water in agriculture i.e., drought and flooding affect physiological and growth aspects of the plant as well as gene expression undertaken in water absorption. These affect depend on the stress duration i.e., shock or gradual stress exposer. The factorial experiment based on CRD with 10 replicates was conducted to investigate the physiological and water relation as well as aquaporin expression in (Capsicum annuum L.). Drought stress was applied gradually from – 2, − 3, − 4 to − 5 MPa during 8 days but in shock stress − 5 MPa applied at one time. The gradual flooding stress adjusted with changing the aeration duration from 15 to 0 min gradually every 2 days and for the shock- flooding, peppers keep in a nutrient solution without aeration in a sealed container. Results showed that both extreme water stress had a deleterious effect on the growth and physiological parameter of pepper for a longer duration. Antioxidant, proline, fluorescence chlorophyll stimulate in the gradual period except for ABA content, which is higher in shock stress. PIP1expression showed a reverse effect in leaf and root at flooding i.e., PIP1expression raised in root while it was reduced in leaf at shock-flooding. The highest PIP1expression was observed in gradual-drought of root and gradual duration of drought and flooding stress in leaf. In the physiological aspect of plant response to stress in pepper, results showed an enhanced in proline and phenol content to help osmotic adjustment and keep water status in moderate condition. Conclusively, shocked stress first, motivated these defense systems, and then in the next step, the other adaptive mechanism like gene expression activated to help pepper face stress. On the other hand, shock stress showed down-regulation, but when the stress lasted for a longer time results in up-regulation.