Effect of drought stress and water recovery on endogenous hormone content in roots of pea

Pot experiment was conducted to determine the content of endogenous hormone, including Abscisic acid (ABA), Indole-3-acetic acid (IAA), Gibberellins (GA) and Zeatin (ZT), in the roots of pea (Pisum sativum Linn.) under drought stress and water recovery. The results indicate that different degrees of drought stress increase ABA and IAA contents while decreasing the contents of GA and ZT. With severe drought stress, the effects generally tend to increase. Different degrees of drought stress leads to different proportions of endogenous hormones in the roots at different growth stages. Drought has considerable impact on ZT/ABA, GA/ABA, GA/IAA and ZT/IAA ratios. But drought effect on ZT/GA, IAA/ABA ratios is insignificant. There is compensation effect of water recovery after drought stress on the 4 endogenous hormones at every growth stage which varies with growth stage, drought stress intensity and water recovery rate. Water recovery leads to variations in endogenous hormones ratio.