Impact of heat and drought stress on physiological response of Terminalia arjuna grown under elevated temperature condition: An adaptive mechanism to climate change

Abstract

Plant growth and productivity is adversely affected by nature’s wrath in the form of various biotic and abiotic stress factors. Increased atmospheric temperature, water deficit condition (drought) is among the major abiotic stresses which adversely affect tree growth and yield. As global climate warms, plant growth behaviour and distributions are predicted to be influenced due to elevated seasonal temperature regimes. Critical to understanding potential of forest shifts is gaining a better understanding of warming effects on young tree seedlings, the survival and growth of which will influence future forest composition. The present study was conducted in controlled environmental conditions with aim to investigate the impact of elevated temperature (40±1.5 0C) along with drought situation on physiological behaviour and their adoptive nature to changing climatic situation on Terminalia arjuna's seedlings. Five months old seedlings with uniform size were grown in pots under controlled condition of elevated temperature of Open Top Chamber circumstances. A set of five seedlings were placed outside chamber which was considered as controlled (35±1) under natural condition i.e. ambient condition. The plant traits associated to physiological factors were measured. Physiological traits were found to be adoptive under elevated temperature and drought condition. Transpiration rate, water use efficiency, stomatal conductance, mesophyll efficiency, photosynthesis rate was positively responded and achieved by plants of elevated temperature. Under elevated temperature condition with drought, transpiration rate was 0.25 mmol m-2 s-1, water use efficiency (Pn/E) was 28.37% more efficient under drought condition while stomatal conductance was 0.025 mmol m-2 s-1. In carboxylation efficiency only slight difference were observed under OTC.