Abstract: To explore the effect of water stress on the physiology of quinoa in different developmental stages, the drought stress with 30% polyethylene glycol 6000 (PEG6000) and the waterlogging stress with the double basin method were performed to treat the quinoa plants of different developmental stages to determine the content of osmotic substances and physiological indexes. The results showed that, compared with the control group, under drought and waterlogging stresses, the soluble protein (SP) content in the quinoa at four stages showed no significant difference, but the soluble sugar content decreased at seedling stage and increased at other stages significantly. Under drought stress, the activity of peroxidase（POD）displayed no obvious change at filling stage, but it increased significantly at other stages. Malondialdehyde（MDA）content increased at squaring and flowering stage, while it decreased or had no obvious change at other stages. Under waterlogging stress, POD activity of quinoa increased significantly at four stages. MDA showed increased content at squaring stage and a normal content at other stages. These results indicated that quinoa could reduce the adverse effect of water stress by increasing the content of WSS and POD activity. Drought had a great influence on the quinoa at squaring and flowering stages, and waterlogging had a great influence on the quinoa at squaring stage, and quinoa showed a strong tolerance to water stress at seedling and grouting stages.

Key words: quinoa, water stress, osmotic substance, physiological indicator