MORPHOLOGICAL, PHYSIOLOGICAL AND BIOLOGICAL OVERVIEW ON FOUR TROPICAL FOREST TREE SPECIES UNDER DIFFERENT DROUGHT AND SALINITY INTERACTION STAGES

Plants suffered majorly when encountered the combined drought and salinity stresses. In current study, different levels of combined drought and salinity stresses impact on growth characteristics, some physiological and biochemical parameters of Tectona grandis, Gmelina arborea, Dalbergia latifolia and Pongamia pinnata seedlings have been examined. The pot culture method adopted in the CRBD manner for one year. Stress conditions were set according to CPE values, PWP and saline water respectively. Five treatments viz: control, 4 dS/m + moderate drought, 4 dS/m + severe drought, 8 dS/m + moderate drought, and 8 dS/m + severe drought, were considered to perform the experiment. The height, collar diameter, total biomass and leaf size reduced with the increasing combined drought and salinity levels in each species seedlings. This also includes reduction of photosynthetic rate, stomatal conductance, transpiration rate, total chlorophyll content, protein and ascorbic acid (T. grandis). The ascorbic acid in the rest of the species and proline content come up with the reverse trend. D. latifolia seedlings exceptionally showed higher growth, physiological and biochemical performances under severe drought conditions at the same salinity level. Furthermore, evaluation of tree species for drought and salinity stresses can help in raising plantations in such areas.