Abstract

The effect of ultraviolet (UV) radiation on the water-logging resistance of Tibetan peach (Amygdalus mira Koehne) remains unclear. In this study, Tibetan peach seedlings were subjected to 9-days of UV-B (280 - 320 nm) supplementation, water-logging or the combination of both, and the growth indicated by leaf number, net photosynthetic rate and stomatal conductance were monitored. In addition, the activities of protection enzymes SOD and POD, as well as the concentrations of hormones ABA, ZR, GAs and ZR in leaves were examined. The results show that UV-B or water-logging or the combination of both factors restrained the growth trend, net photosynthetic rate and stomatal conductance. Both UV-B and water-logging increased SOD activity, and synergistically led to a drastic increase in POD activity. Furthermore, UV-B and water-logging condition increased the concentrations of ABA, ZR and GAs, while it decreased ZR. The results suggest that the changes of hormone concentrations in Tibetan peach leaves may explain the increased activities of protection enzymes and decreased photosynthesis under water-logging condition.

Key words: Tibetan peach, water-logging, UV-B, photosynthesis, protection enzymes, hormones.

Abbreviation

ABA; abscisic acid, GA; gibberellic acid, IAA; indole-3-acetic acid,ZR; zeatin riboside, SOD; superoxide dismutase, POD; peroxidase.