Response of Gas Exchange Activity and Relative Water Content of Neem in Relation to Weather

Neem is known for its medicinal values and is a hardy plant that can grow in a wide variety of environmental conditions. However, productivity is impacted by unfavourable weather conditions due to different geographical locations. The present study was conducted to study the influence of prevailing weather conditions on certain physiological parameters deciding the reproductive ability of neem trees. The study was conducted in two different locations at different agro-climatic regions of Tamil Nadu, India. Gas exchange parameters like photosynthetic rate, stomatal conductance, transpiration rate and leaf temperature and relative water content during pre-flowering, flowering and post-flowering stages were measured and correlated with temperature, relative humidity, precipitation and wind speed observed from the corresponding location. In both locations, the neem trees recorded significantly higher values for these physiological parameters during the pre-flowering and fruiting stages compared to the flowering stage. The trees with higher Diameter and breast height (DBH) showed higher values for gas exchange parameters compared to the trees with lower DBH.