Abstract: The comparative experiments were conducted to study the difference between direct-seeded dry cultivation with plastic film mulching(DC) and conventional paddy cultivation(PC) in physiological characteristics of root and leaf,and its influence on grain yield in early-season indica rice.Under DC conditions,the rice had lower 1000-grain weight,which was one of the most important factors resulting in lower grain yield in comparison to PC.The lower grain weight under DC was mainly attributed to early and quick senescence of rice root and leaf at the grain-filling stage,showing that the activity of root system,chlorophyll content,leaf area index and net photosynthetic rate were reduced faster,and the superoxide dismutase and peroxidase activities in flag leaf were reduced quickly but the malondialdehyde content in flag leaf increased from heading to maturity under DC.Therefore,it is very important to slow down the rate of senescence in root system and leaf at the grain-filling stage for higher yield under DC.

Key words: early-season indica rice, direct-seeded dry cultivation with plastic film mulching, root system, leaf, physiological characteristics, grain-filling stage

摘要： 对早稻直播覆膜旱作与常规水作栽培对灌浆成熟期根叶生理特性及产量的影响进行了比较研究。与常规水作栽培水稻相比，直播覆膜旱作早稻千粒重显著下降，是导致产量明显下降的主要原因之一。而粒重的下降则主要归因于直播覆膜旱作较常规水作水稻灌浆成熟期根叶生理机能的衰退要快，表现为根系活力、叶片叶绿素含量、叶面积指数、净光合速率等下降较快，叶片超氧化物歧化酶、过氧化物酶等保护酶活性迅速下降，而丙二醛含量较高，使籽粒干物质积累受阻，揭示出提高灌浆成熟期根叶生理机能是进一步提高直播覆膜旱作早稻粒重和最终产量的重要途径。

关键词: 早籼稻, 直播覆膜旱作栽培, 根系, 叶, 生理特性, 籽粒灌浆期