Abstract: Water content (WC), sap flow and changes in relative water content (RWC) of rice plants damaged by brown planthopper (BPH), were determined in laboratory, and the tolerance of rice plants with different nitrogen regimes to BPH was evaluated in greenhouse at International Rice Research Institute (IRRI). Results indicated that both WC and RWC were increased significantly, while the sap amount flowed from rice plants were reduced statistically, with the increase of nitrogen content in rice plants. RWC in rice plants applied with high nitrogen fertilizer decreased strongly by the injury of BPH nymphs. Those may be considered to be one of the key factors to increase the susceptibility to BPH damage on rice plants applied with nitrogen fertilizer.

Key words: brown planthopper, nitrogen, relative water content, sap flow, tolerance, rice

摘要： 在实验室测定了不同含氮量稻株的含水量和叶鞘伤流液以及被褐飞虱为害后稻株相对含水量的变化，在温室监测和评价了不同氮肥施用量条件下稻株对褐飞虱的耐性。结果表明，随着稻株含氮量的增加，稻株的含水量和相对含水量均显著增加，但叶鞘伤流液总量却明显减少。被高密度的褐飞虱若虫为害后，高氮肥施用量稻株的相对含水量显著低于低氮肥施用量稻株的相对含水量。这些结果可能是高氮肥条件下稻株对褐飞虱为害的敏感性增加的主要原因。

关键词: 褐飞虱, 氮素, 相对含水量, 伤流液, 耐性, 水稻