中文摘要：

选择品种粳籼89，设计水分和养分能自由通过而根系不能穿过的根袋[根袋d分别为3、4、5cm，h为25cm]，通过水培试验研究水稻根系在根袋处理后对不同光照强度条件的反应．结果表明，在相同光照水平条件下，不同根袋处理对植株地上部干物质积累和茎鞘贮存性碳水化合物含量无显著影响，而对地下部影响较大．根袋处理后根质量和根冠比明显降低，而且根袋越小，降低得越严重．而遮阴处理无论是抽穗期还是成熟期根系和地上部干物质积累明显下降，根系体积降低，叶片叶绿素含量降低．遮阴70％处理后无论是抽穗期还是成熟期，较大根袋处理（d=5cm）的根系吸收能力均比不套根袋处理有提高的趋势，其中在抽穗期根系总吸收面积、活跃吸收面积和比表面积分别增加57．7％、26．0％和41．5％，成熟期活跃吸收面积、活跃吸收面积所占比例分别增加74．1％、58．2％，均达显著水平．

英文摘要：

A hydroponic experiment was conducted to study the physiological response of rice plant to different light intensity after decreasing root/shoot ratio. Root system was placed in cylindrical nylon bags to cause root confinement. The diameters of the root bags were 3, 4, 5 cm, respectively and the height was 25 cm. The results showed that under the same shading level, root confinement had no significant effects on the dry matter accumulation in the aboveground parts, but had significant effects on underground parts. The root mass and root/shoot ratio decreased significantly after root confinement, the smaller the root bag, the more the root/shoot ratio reduced. After shading, root and shoot dry matter accumulation, root volume, leaf chlorophyll content reduced significantly at heading and ripening stage. Under 70% shading treatment, the total surface area, active area and surface area per volume of the root system in 5 cm treatment increased by 57.7% ,26. 0% ,41.5% at heading stage, and the active area and percentage of active area of root system increased by 74. 1% , 58.2% at ripening stage compared with control.