Wang Xinpeng, Liu Hualong, Ma Huimiao, Dang Yuxiang, Han Yiming, Zhang Can, Liu Aixin, Zou Detang, Wang Jingguo, Zhao Hongwei
Key Laboratory of Germplasm Enhancement, Physiology and Ecology of Food Crops in Cold Region, Ministry of Education, Northeast Agricultural University, Harbin, 150030, Heilongjiang, China.
Sci Rep. 2025 Apr 8;15(1):11973. doi: 10.1038/s41598-025-85598-8.
Drought stress at jointing and booting stages of plant development directly affects plant growth and productivity in rice. Jointing and booting stages may overlap in high-latitude areas where water deficits occur. However, little is known about the effects of photosynthesis on grain sucrose metabolism and the differences of sucrose metabolism strategies between superior and inferior grains under different drought stress was unclear. In this study, rice plants were subjected to drought stress for 15 days at jointing-booting. Drought stress affected normal leaf growth, and decreased the leaf area index linearly. Short-term mild drought stress had positive effects on photosynthesis, but long-term drought stress reduced the transpiration rate, stomatal conductance, and intercellular CO concentration. Stomatal conductance increased with drought stress duration but increased intercellular CO concentration did not prevent decrease in net photosynthetic rate. Vacuolar invertase activity was important for panicle development (where its activity differed between superior and inferior grains), but not for rice grain filling. Vacuolar invertase activity of drought-sensitive rice varieties superior grains increased by 111.24%~118.46% under drought stress. Drought stress reduced sucrose-phosphate synthase activities in superior and inferior grains. SuSase activity of inferior grains affected sucrose content significantly.
水稻拔节孕穗期的干旱胁迫直接影响植株生长和产量。在高纬度缺水地区，拔节期和孕穗期可能重叠。然而，关于光合作用对籽粒蔗糖代谢的影响以及不同干旱胁迫下优、劣势籽粒蔗糖代谢策略的差异尚不清楚。本研究中，水稻植株在拔节孕穗期遭受15天的干旱胁迫。干旱胁迫影响叶片正常生长，叶面积指数呈线性下降。短期轻度干旱胁迫对光合作用有积极影响，但长期干旱胁迫降低了蒸腾速率、气孔导度和胞间CO₂浓度。气孔导度随干旱胁迫持续时间增加，但胞间CO₂浓度增加并不能阻止净光合速率下降。液泡转化酶活性对穗发育很重要（其活性在优、劣势籽粒间存在差异），但对水稻籽粒灌浆不重要。干旱胁迫下，干旱敏感型水稻品种优势籽粒的液泡转化酶活性提高了111.24%~118.46%。干旱胁迫降低了优、劣势籽粒中蔗糖磷酸合成酶的活性。劣势籽粒的蔗糖合成酶活性显著影响蔗糖含量。
