外源油菜素甾酮处理水稻对褐飞虱取食和产卵选择性等行为的影响
The effects of exogenous castasterone treatment on rice brown planthopper Nilaparvata lugens behaviors, with special reference to feeding and ovipositing preferences

为了解经油菜素甾酮处理后水稻对褐飞虱Nilaparvata lugens的抗性，通过在水稻培养液中添加不同浓度的油菜素甾酮，观察水稻对褐飞虱取食和产卵、若虫生长发育、羽化等行为的影响，评估油菜素甾酮在水稻抗虫防御反应中的作用。结果表明，水稻培养液中的油菜素甾酮可被水稻有效吸收并产生生理活性。经0.01~10 μmol/L油菜素甾酮处理后水稻叶片弯曲程度均显著增加，其叶角分别为对照的3.3~11.0倍。褐飞虱取食和产卵嗜好性与油菜素甾酮处理浓度密切相关，经较低浓度0.005~0.05 μmol/L油菜素甾酮处理的水稻能显著降低褐飞虱雌成虫的取食和产卵嗜好性，其产卵量为对照的35.0%~73.9%；而较高浓度0.1~5 μmol/L油菜素甾酮处理则增加褐飞虱雌成虫的取食和产卵嗜好性，其产卵量为对照的1.3~1.8倍。0.01、1、5、10 μmol/L油菜素甾酮处理的水稻显著降低褐飞虱若虫的羽化率，为对照的32.5%~53.3%。0.1~10 μmol/L油菜素甾酮处理显著缩短褐飞虱若虫发育历期，仅为对照的94.1%~96.9%。褐飞虱若虫存活数和初羽化雌成虫体重分别仅在0.1、10 μmol/L油菜素甾酮处理下显著降低。表明油菜素甾酮处理水稻可对水稻抗虫防御反应产生影响，其具有作为生态功能分子用于褐飞虱田间防控的潜力。
To determine the effects of castasterone (CS) on the rice resistance against rice brown planthopper (BPH), Nilaparvata lugens (St？l), behaviors such as feeding and oviposition preferences, developmental duration and emergence rates of nymphs, BPHs fed on rice plants grown in culture solution with different concentrations of CS were observed. The results showed that CS could be absorbed from culture solution and induce physiological activity in rice, as CS-treated rice leaf angles were bigger than those of the control; 0.01-10 μmol/L CS-treated rice leaf angles were 3.3-11.0 times of the control. The effects of CS on the feeding and oviposition preferences of female BPH adults were dependent on the concentration of CS, and BPH did not prefer to feed and oviposit on low-concentration CS-treated rice plants:the eggs on 0.005-0.05 μmol/L CS-treated rice plants were 35.0%-73.9% of those on the control. Moreover, BPHs preferred to feed and oviposit on higher-concentration CS-treated rice plants:the eggs on 0.1-5 μmol/L CS-treated rice plants were 1.3-1.8 times of those on the control, and the emergence rates of BPH nymphs fed on 0.01, 1, 5, 10 μmol/L CS-treated rice plants were only 32.5%-53.3% of that of the control, all of which were significantly reduced compare to the control; the developmental durations of BPH nymphs fed on 0.1-10 μmol/L CS-treated rice plants were significantly decreased, about 94.1%-96.9% of that of the control; the nymphal numbers of BPH survived fed on 0.1 μmol/L CS-treated rice plants and the weight of freshly emerged female adults on 10 μmol/L CS-treated rice plants were significantly reduced compared to those of the control. The results indicated that castasterone could regulate rice defense responses against herbivores, which could be used for BPH population control in the field as an ecological functional molecule.