Up-regulation of photosynthesis and sucrose-P synthase in rice under elevated carbon dioxide and temperature conditions

Abstract

Basmati rice (Oryza sativa L.) cultivars viz. PRH-10 (pusa rice hybrid-10) and PS-2 (Pusa Sugandh-2) were grown under two different day/night temperatures (31/24°C, 35/28°C) at ambient (370 μmol/mol) and elevated (550 μmol/mol) carbon dioxide (CO2) concentration, respectively, to characterize how an increase in CO2 and temperature affects rice photosynthesis and carbohydrate metabolism. At elevated CO2, the photosynthetic rates increased under both the temperature regimes, compared with plants grown at ambient CO2. The photosynthetic rate, sucrose-P synthase (SPS) activity and accumulation of soluble sugars and starch were higher in PRH-10 (pusa rice hybrid-10), compared to PS-2 (Pusa Sugandh-2). Elevated temperature decreased the photosynthetic rates both under ambient and elevated CO2 conditions. The SPS (sucrose-P synthase) activity and the accumulation of soluble sugars and starch were enhanced at elevated CO 2 under both temperature regimes compared with plants grown at ambient CO2. The up-regulation of SPS (sucrose-P synthase) under elevated CO2 and temperature would be beneficial for growth and productivity of rice plants for the future climatic conditions.