Seasonal changes of endogenous ABA and cytokininsin environmental adaptation of differentecotypes of reed plants

The roots and leaves of four reed ecotypes (Phragmites communis Trinius) growing in the desertregions of northwest China were determined for the levels of abscisic acid (ABA) and cytokinins isopenteny-ladenosine (iPA) and zeatin riboside (ZR) ] using an enzyme linked immunosorbent assay (ELISA) through-out the whole of growing season. Three terrestrial reed ecotypes in drought and saline habitats contained moreABA than swamp reed during the main stages of the growing season. The ABA levels in the roots of theseterrestrial red ecotypes were higher in spring and autumn than in summer , an opposite situation was observedin their leaves. All reed ecotypes contained more iPA and ZR in the leaves than in the roots, and the decreasein iPA and ZR levels was found in both of tissues with thE passage of the season. Compared to the swamp reedecotype, three terrestrial reed ecotypes showed an increase of ABA and a decrease of cytokinins in the rootsand leaves. These results were primarily discussed in relation to the environmental adaptation of resd plants.