作物学报2025，Vol.51Issue(5)：1347-1362,16.DOI:10.3724/SP.J.1006.2025.42046
水稻幼穗分化期至抽穗期高温对籽粒形态和充实的影响及其与粒重的关系
Effect of high temperature during the panicle initiation and heading stages on grain shape and filling and its relationship with grain weight in rice
摘要
Abstract
A pot experiment was conducted with two temperature treatments—normal temperature treatment and high temperature treatment during the panicle initiation and heading stages—using three rice varieties:heat-sensitive varieties Liangyoupeijiu(LYPJ)and Jingliangyouhuazhan(JLYHZ),and heat-tolerant variety Shanyou 63(SY63).The objective was to investigate the effects of high temperature during the panicle initiation and heading stages on spikelet and grain size,grain filling,and their rela-tionship with grain weight.Compared to normal temperature,high temperature significantly reduced thousand-grain weight,spikelets per panicle,seed setting rate,and yield in LYPJ and JLYHZ,but had no significant effect on SY63.High temperature also significantly decreased spikelet and grain size(length,width and thickness)in the heat-sensitive varieties,while SY63 exhib-ited only minor reductions.Additionally,high temperature significantly downregulated the expression of OsLOGL2 in spikelets of LYPJ and upregulated the expression of OsCKX5 in spikelets of JLYHZ,resulting in reduced endogenous active cytokinin levels in spikelets.High temperature decreased the harvest index but had no significant effect on aboveground dry weight at the maturity stage.It also significantly reduced single-grain weight accumulation and the average grain filling rate during the heading and ma-turity stages in the heat-sensitive varieties,with no significant changes observed in SY63.Furthermore,high temperature treat-ment significantly reduced the expression of grain filling-related genes(OsFLO2,OsFLO4 and OsGIF2)and the activities of key enzymes involved in grain filling,including acid/neutral invertases,sucrose synthetase,and ADP-glucose pyrophosphorylase,in the heat-sensitive varieties.Starch branching enzyme activity in grains was also significantly reduced in LYPJ,while these en-zymes and genes were unaffected in SY63.This study demonstrates that high temperature during the panicle initiation and head-ing stages reduces the harvest index and decreases spikelet and grain size by lowering active cytokinin levels in spikelets.It also hinders grain filling by suppressing the expression of grain filling-related genes and enzyme activities.These findings suggest that the reductions in grain weight and yield under high temperature are likely due to decreased assimilate allocation to panicles and reduced sink activity,highlighting the adverse effects of heat stress on grain development and yield.关键词
水稻/幼穗分化期-抽穗期高温/粒重/籽粒形态/籽粒充实/颖花细胞分裂素含量Key words
rice/high temperature,panicle initiation-heading stage/grain weight/grain shape/grain filling/content of cytokinins in spikelets引用本文复制引用
王梦宁,谢可冉,高逖,王飞,任孝俭,熊栋梁,黄见良,彭少兵,崔克辉..水稻幼穗分化期至抽穗期高温对籽粒形态和充实的影响及其与粒重的关系[J].作物学报,2025,51(5):1347-1362,16.基金项目
本研究由国家自然科学基金项目(31871541)和财政部和农业农村部国家现代农业产业技术体系建设专项(CARS-01)资助. This study was supported by the National Natural Science Foundation of China(31871541)and the China Agriculture Research System of MOF and MARA(CARS-01). （31871541）
