Combining IR imaging, chlorophyll fluorescence and phenomic approach for assessing diurnal canopy temperature dynamics and desiccation stress management in Azadirachta indica and Terminalia mantaly

Infrared (IR) imaging, chlorophyll fluorescence imaging and plant phenomic approach were used to study physiological mechanism of desiccation tolerance in Azadirachta indica and Terminalia mantaly during the period of November 2018 to February 2019. IR imaging instrument was installed in the field for monitoring the canopy temperature dynamics of different canopy level including stem region of the tree throughout the day. Maximum photochemical efficiency (Fv/Fm) was measured with chlorophyll fluorescence measuring system for sun exposed leaves of A. indica and T. mantaly over a period of desiccation. In order to reveal complete understanding of physiological mechanism of desiccation tolerance, plant phenomic approach was used for assessing response of these tree species to exposed desiccation. Results indicated that canopy temperature of upper foliage, lower foliage, stem (trunk) region of A. indica were quite higher during the hotter period of the day as compared to T. mantaly and maximum photochemical efficiency (Fv/Fm) was maintained in A. indica leaves as compared to T. mantaly for same exposed duration of desiccation. Plant phenomic approach also depicted that A. indica twig retained more tissue water and maintained canopy volume area higher than T. mantaly. Thus it provides an indication that A. indica tree is quite desiccation tolerant than T. mantaly by maintaining its canopy temperature, maximum photochemical efficiency, more tissue water and canopy area.