Abstract: To understand the relationship between rice tolerance and endogenous plant hormones under Nilaparvata lugens infestation, the response of abscisic acid (ABA) in roots and leaves at the tillering and grain-filling stages of representative rice varieties （super-high yield rice Peiai 64S/E32，Xieyou 963 and TN1）to N. lugens nymph infestation was studied using enzyme-linked immunosorbent assay （ELISA）. The results indicated that ABA contents in leaves at 3 d after N. lugens infestation at the tillering stage for superhigh yield rice Peiai 64S/E32 and TN1 significantly increased. Ratio of ABA contents in roots to those in leaves （R∶L ratio） decreased significantly. ABA contents in leaves at 6 d after infestation for super-high yield rice Peiai 64S/E32 significantly decreased, but the R∶L ratio significantly increased. But ABA contents in leaves of TN1 significantly increased and the R∶L ratio decreased. At the grain-filling stage, change of ABA for Xieyou 963 was similar to Peiai 64S/E32 at the tillering stage. For TN1, ABA contents in leaves at 3 d after infestation increased and the R∶L ratio decreased. ABA contents in leaves at 6 d after infestation for 40 nymphs per plant and the R∶L ratio increased. Percent of increase or decrease of ABA contents showed that change of ABA contents at the tillering stage was greater than that at the grain-filling stage, and that for tolerant variety was greater than that for susceptible rice variety, but the effective duration was shorter. The change of ABA contents in leaves was greater than that in roots. Comparison of change of ABA contents of the two rice varieties showed that, for tolerant rice variety, ABA contents in leaves at 3 d after infestation increased and those at 6 d after infestation decreased, and the R∶L ratio at 3 d after infestation decreased, that at 6 d after infestation increased; while for the susceptible rice variety, ABA contents in leaves at 3 d and 6 d after infestation increased and the R∶L ratio decreased at the tillering stage at 3 d and 6 d. At the grain-filling stage, the R∶L ratio at 3 d after infestation decreased while that at 6 d after infestation increased. The change of ABA contents in roots after N. lugens infestation was not distinct. The results demonstrated that the effect of N. lugens on ABA contents in plants varied with rice variety （tolerant and susceptible）. The findings have scientific value for ascertaining the tolerance mechanism of rice variety.

Key words: Nilaparvata lugens, rice variety, plant resistance, roots, leaves, abscisic acid (ABA) content