| A study was conducted, using some physiological parameters related to water relations of plants such as water potential, soluble protein, net photosynthetic rate, stomatal conductance, and so on, to determine the responses of three tree species Populus alba x Populus breolinensis, Ulmus pumila L. and Betula platyphylla to drought in order to explore the regulative mechanism of exogenous substances in the drought-resistance of seedlings. By means of pot-cultivated experiment , two-year-old seedlings of these three species were treated with different concentrations of Multi-Effect-triagle (MET), mimic acid and abscisic acid. Responses of seedlings for these three tree species to drought were synthetically evaluated by principal component analysis, and the most effective specie and concentration proportion of exogenous substances were screened out. The data acquired in this study showed that the resistances of three species experimented were improved after application of MET at 250, 1000 and 750mg/L.The effect of humic acid with the concentration of 850mg/L on improving the drought-resistance of Populus alba x Populus breolinensis seedlings was very obvious, and favorable regulative effects of humic acid with the concentrations of 850 and 650 mg/L on Ulmus pumila seedlings were also observed, but the effect of humic acid on Betula platyphylla seedlings was not distinct. The drought-resistance of Populus alba x Populus breolinensis seedlings treated with abscisic acid of 2~3mg/L can be significantly improved, and abscisic acid with the concentrations of 1-2 mg/L and 4 mg/L had better regulative effects on Ulmus pumila and Betula platyphylla seedlings, respectively. MET, as a retardant, can reduce cell volume so as to increase relative concentration of cell to control (ck).
|
PDF Full Text Request