%0 Research article
%T Adaptive responses to progressive drought stress in two poplar species originating from different altitudes
%A Yang, Fan
%A Miao, Ling-Feng
%D 2010
%J Silva Fennica
%V 44
%N 1
%R doi:10.14214/sf.160
%U https://silvafennica.fi/article/160
%X Cuttings of Populus kangdingensis C. Wang et Tung and Populus cathayana  Rehder, originating from high and low altitudes in the eastern Himalaya,  respectively, were examined during one growing season in a greenhouse  to determine the effects of progressive drought stress. The results  manifested that the adaptive responses to progressive drought stress  were different in these two species from different altitudes.  Significant changes in stem height, leaf development, relative water  content (RWC), malondialdehyde (MDA) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)  appeared earlier in P. cathayana than in P. kangdingensis, whereas  changes in soluble protein, soluble sugar, free proline and antioxidant  enzymes appeared earlier in P. kangdingensis. In addition, changes in  these parameters became more and more significant when the drought  stress progressed, especially under severe drought stress in P.  cathayana. Plant growth showed significant positive correlations with  soluble proteins and sugars, free proline and antioxidants and a  significant negative correlation with RWC under water stressed treatment  in two poplar species. Compared with P. cathayana, P. kangdingensis was  able to maintain a superior height growth and leaf development under  drought stress. Also, P. kangdingensis possessed greater increments in  soluble protein, soluble sugar, free proline and antioxidant enzymes,  but lower increments in MDA and H<sub>2</sub>O<sub>2</sub> than did P.  cathayana when the cuttings were exposed to progressive drought stress.  Our results suggest that P. kangdingensis originating from the high  altitude has a better drought tolerance than does P. cathayana  originating from the low altitude. Furthermore, this study manifested  that acclimation to drought stress are related the rapidity, severity,  duration of the drought event and the altitude of two poplar species.