Response of five introduced Fraxinus chinensis species to drought stress in Yili area.
To provide a theoretical basis for future regional promotion and cultivation of Fraxinus chinensis, the difference of drought resistance of five introduced Fraxinus species in Yili was analyzed. The study used five three\|year\|old Fraxinus chinensis seedlings with four potted water control treatments of 80%~85%, 55%~60%, 40%~45%, and 30%~35% field moisture capacity as CK, T1, T2, T3. The SOD activity, POD activity, MDA content, proline content, soluble protein content, chlorophyll content, and net photosynthetic rate (Pn) were tested. The principal component analysis, membership function and multiple stepwise regression were used to evaluate the drought resistance of five introduced Fraxinus chinensis species. The results were as followes: (1) Under drought stress, proline content and soluble protein content increased significantly compared with the control. The proline content of Fraxinus velutina 'Yuanla-1' increased by 361.85% under T2 treatment, and the soluble protein content of F. chinensis 'Lula-5' increased by 284.87% under T3 treatment. (2) With the increase of drought stress, the POD activity of five species of Fraxinus chinensis increased continuously, and the POD activity of '1275' in T3 treatment increased by 373.88% compared with the control. Compared with the control, the activity of SOD in each treatment group of five species of Fraxinus chinensis increased, and that of F. chinensis 'Jinye' increased by 118.70% under T3 treatment. The MDA content of F. chinensis 'Jinye' was lower, but the change of MDA was not significant. The MDA content of four species in the treatment groups was significantly higher than that in the control group. (3) With the increase of drought stress, the chlorophyll content of five species of Fraxinus chinensis decreased continuously. The Pn decreased significantly, and the chlorophyll content was highly significantly correlated with Pn. The chlorophyll content of F. chinensis 'Jinye' decreased by 55.51% in T3 treatment, and the Pn decreased by 81.08% in F. chinensis 'Lula-5' T3 treatment. The order of drought resistance of chosen five Fraxinus chinensis was F. chinensis 'Lula-5'>1275> F. chinensis 'Lula-6'> F. velutina 'Yuanla-1' > F. chinensis 'Jinye'.