The Effects of Thermal and Waterlogging Stresses at Booting Stage on Photosynthesis and Yield of Rice

Abstract

【Objective】 Crops often endure various biotic and abiotic stresses during their growth. This paper investigates how thermal and waterlogging stresses occurring at booting stage affect photosynthesis and the ultimate yield of paddy field rice. 【Method】 The experiments were conducted in pots and consisted of four treatments: waterlogging stress by keeping the water on the soil surface 15 cm deep (T1), higher them stress (T2), high thermal stress combined with the waterlogging stress (T3). Conventional irrigation with water on the soil surface kept at 0~5 cm deep was taken as the control (CK). In each treatment, we measured the change in SPAD, photosynthetic traits and yield of the rice. 【Result】 Compared to CK, T2 reduced the photosynthetic rate by 30.77%, while T3 increased SPAD, photosynthetic rate and stomatal conductance of the leaves by up to 51.90%. Compared to CK, the impact of the stresses occurring at booting stage on shoot growth lasted into mature stage. It hence reduced the yield, especially T2 and T3 which reduced the rice yield by 80.09% and 12.33%, and 1 000-grain weight by 16.31% and 11.86% respectively. 【Conclusion】 To alleviate the adverse impact of thermal stress at the booting stage on yield, water in the soil surface should be kept about 15 cm deep to ameliorate the potential thermal damage.

Keywords

• rice
• thermal and waterlogging stress
• spad
• photosynthetic traits
• yield