THE RELATIONSHIP BETWEEN THE MORPHOLOGICAL AND STRUCTURAL CHANGES OF POPULUS EUPHRATICA OLIV. AND ENDOGENOUS HORMONE CONTENTS

Populus euphratica Oliv. exhibits heterophylly, which is regarded as a manifestation of evolutionary adaptation to extremely arid environments. To clarify the relationship between Morphological and structure changes of P. euphratica (Populus euphratica Oliv) and its physiological characteristics, we studied the changes in the morphological structures, carbohydrates, endogenous hormone levels and their ratios, as well as their relationships during the developmental stages, and heterophylly at crown height. Correlation analysis shows, IAA and GA(3) contents, as well as the ratios of IAA/ABA, GA(3)/ABA and ZR/ABA, were negatively correlated with LW and LA and were positively correlated with LL and LI. IAA, ZR, IAA/ABA, and ZR/ABA were negatively correlated with LT. GA(3), IAA, GA(3)/ABA, and IAA/ABA were significantly or extremely significantly correlated with ECN, PTCL, PTT and PSR. The content of soluble sugar, starch and soluble protein were positively correlated with the LI and negatively correlated with LA, PL, LW, ECN and PTC. P. euphratica regulates the drought resistance at different developmental stages by changing the content and ratio of 4 hormones in heterogeneous leaves and the synergistic changes of some anatomical structures, and adapts to arid environment.