Deciphering endurance capacity of mango tree (Mangifera indica L.) to desiccation stress using modern physiological tools

Abstract

• Mango plant can maintain its canopy coolness during desiccation period by its ability to with draw water during water limiting conditions. • Mango plant can maintain its carboxylation capacity during hotter period of the day. • Crucial components of photosynthesis, PSII efficiency is maintained during desiccation period, thereby preventing the plants from desiccation damage and providing tolerance mechanisms. • Mango plant can maintain its structural attributes (mainly by maintaining turgidity due to water retention capacity) such as convex hull area, which also supports desiccation tolerance mechanisms. Capacity of mango tree to withstand drought (absence of soil moisture) can be attributed to stress resilient physiological processes inside the cell and also at whole plant level. To test this hypothesis, photosynthetic traits were recorded over the period of time. Further, desiccation tolerance of photosystem II (PSII) in excised mango leaves were measured by employing chlorophyll fluorescence imaging system. Beside this, the capacity of mango tree to keep its canopy cool was monitored in every 10 min interval throughout the day during dry and rainy season in the field by employing thermal imaging system. Finally, phenomics platform was used to monitor depletion of tissue moisture level as well as changes in structural attributes during desiccation in excised shoots of the tree. It was inferred that mango tree can maintain its carboxylation efficiency over the period of time. IR studies confirmed that mango tree maintained its canopy coolness during dry season. In addition, the chlorophyll fluorescence experiments revealed that mango leaves retained 50% of initial PSII efficiency for as many as 4 days after desiccation and chlorophyll fluorogram also depicted the observations. Phenomics studies concluded that mango twig retained tissue water content even up to the 164 h of desiccation with gradual decrease in canopy area. Hence, it is interpreted that these physiological resilience are amongst the various reasons for evergreen feature of mango tree which has tendency to survive severe soil moisture deficit particularly during the summer in tropical and subtropical regions, which has been revealed for first time using phenomics platform.