We investigated the physiological response and compensation mechanism of Lagerstroemia indica seedlings under drought stress and rewatering to provide a reference for the study of drought tolerance mechanisms. In this study, we compared and analyzed the changes in 10 physiological indices of L. indica seedlings after the drought stress (for 30 days) and rewatering (for 7, 14, and 21 days) treatment and conducted a principal component analysis. With the intensification of drought stress, the relative water content of L. indica seedlings decreased, whereas the carotenoid, proline, and soluble protein contents and relative electrical conductivity increased. The chlorophyll and soluble sugar contents and superoxide dismutase and peroxidase activities initially increased but subsequently decreased. The malondialdehyde content varied, with an initial increase, subsequent decrease, and final increase. After rewatering, all physiological indicators, except for malondialdehyde, quickly recovered to the levels of the control seedlings; among them, proline, soluble protein contents, and superoxide dismutase and peroxidase activities produced an overcompensation or compensation effect. However, the most sensitive physiological indices of L. indica seedlings to drought stress and rewatering were soluble sugar, chlorophyll, malondialdehyde, and proline. In the complex process of responding to drought stress and rewatering, L. indica seedlings could effectively regulate the soluble sugar, chlorophyll, and proline contents in vivo to actively respond to drought. When the degree of drought stress did not exceed the tolerance threshold of L. indica seedlings, it could even produce a compensation or overcompensation effect after rewatering, showing their resilience and adaptability.

研究了紫薇幼苗在干旱胁迫和复水条件下的生理反应和补偿机制，为耐旱机制的研究提供参考。本研究比较分析了籼稻幼苗在干旱胁迫（30天）和复水（7天、14天和21天）处理后10个生理指标的变化，并进行了主成分分析。随着干旱胁迫的加剧，籼稻的相对含水量幼苗减少，而类胡萝卜素、脯氨酸和可溶性蛋白质含量和相对电导率增加。叶绿素和可溶性糖含量以及超氧化物歧化酶和过氧化物酶活性最初增加但随后降低。丙二醛含量各不相同，最初增加，随后减少，最后增加。复水后除丙二醛外所有生理指标迅速恢复至对照苗水平；其中，脯氨酸、可溶性蛋白含量、超氧化物歧化酶和过氧化物酶活性产生过度补偿或补偿作用。然而，L. indica最敏感的生理指标对干旱胁迫和复水的幼苗有可溶性糖、叶绿素、丙二醛和脯氨酸。在应对干旱胁迫和复水的复杂过程中，籼稻幼苗能够有效调节体内可溶性糖、叶绿素和脯氨酸含量，积极应对干旱。当干旱胁迫程度不超过籼稻幼苗耐受阈值时，复水后甚至会产生补偿或过度补偿效应，显示出其恢复力和适应性。