Effects of Water Regulation during Panicle Initiation Stage on Photosynthetic Characters and Yield of Rice under Straw Returning

BAI Chenghan; JI Linshuang; WANG Siwen; LIU Liang; MA Wei; LIU Xiaoliang; YANG Yongzhi; SUN Yi'nan; GUO Wanqing; LIN Zhe; HOU Linhan; PIAO Jin; HOU Ligang

doi:10.15933/j.cnki.1004-3268.2025.05.004

Abstract：The treatment without straw returning(A1)and treatment with straw returning(A2)were set up,and the effects of water regulation[mild water control(WP1,Ψsoil=0 kPa),moderate water control(WP2,Ψsoil=-15 kPa),medium-to-severe water control(WP3,Ψsoil=-30 kPa),severe water control(WP4,Ψsoil=-45 kPa),conventional flooding(CK)]during panicle initiation stage on photosynthetic characters[leaf SPAD value,net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)],antioxidant properties[superoxide dismutase(SOD)activity,catalase(CAT)activity and malondialdehyde(MDA)content],yield and its components(number of spikes per hole,thousand-grain weight,number of primary branches,number of grains from primary branches,number of secondary branches and number of grains from secondary branches)were studied,so as to provide a theoretical basis for water management during panicle initiation stage under straw returning condition.The results showed that,the SPAD value,Gs and Tr of A2 treatment were higher than those of A1 treatment under WP1 condition,and the MDA content was lower than that of A1 treatment.The 1 000-grain weight,number of grains from primary branches,number of secondary branches,number of grains from secondary branches and yield of A2 treatment were higher than those of A1 treatment under WP1 and WP2 conditions.Under A1 condition,the SPAD value,Pn,Gs,Tr,CAT activity,SOD activity,yield and its components generally decreased with the decrease of soil water potential;Under A2 condition,the SPAD value,Pn,Gs,Tr,SOD activity,number of panicles per hole,1 000-grain weight,number of secondary branches,the number of grains from secondary branches and yield of WP1 treatment were the highest,and the overall order was WP1>WP2>CK>WP3>WP4.The photosynthetic capacity,antioxidant capacity,yield and its components of A2WP1 treatment were generally the highest,followed by A1CK,A2WP2 treatments.In summary,when the soil water potential was 0 kPa and-15 kPa,returning straw can enhance the photosynthetic capacity and antioxidant capacity of rice leaves,effectively alleviate the adverse effects of water stress on rice leaves,and increase the yield by increasing thousand-grain weight,number of secondary branches and number of grains from secondary branches,and the A2WP1 treatment is the best.