科研之友
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摘要
This study aimed to investigate the effects of simulated acid rain (AR) treatments, differing in pH levels (5.5 (control), 4.5, 3.5 and 2.5), on the antioxidant enzyme activities, growth and fruit yields of pepper and watermelon plants. Results of this study showed that a single application of the AR treatments had no effect on the growth of watermelon plants, whereas significant decreases in the growth and fruit yield of pepper plants were observed at both of the AR-pH 3.5 and AR-pH 2.5 treatments. The stem and leaf dry weight, fruit fresh weight and fruit number of pepper decreased approximately 23, 22, 21 and 30% (P < 0.05) respectively, at the AR-pH 3.5 treatment compared to those of control plants (AR-pH 5.5), while decreases of approximately 29, 22, 39 and 43% (P < 0.05) respectively, were observed at the AR-pH 2.5 treatment. This result indicates that the difference in the reduction of fruit yield of pepper between the AR-pH 3.5 and AR-pH 2.5 treatments was greater than the difference in the reduction of the stem and leaf dry weight between the two treatments. These results coincided with higher degree inhibition and continuing reduction of the APX enzyme activity in the pepper leaves, compared to those of the watermelon plant. Calcium (Ca) and potassium (K) concentrations decreased approximately 22 and 6% (P < 0.05) in the leaves exposed to the AR-pH 2.5 treatment for 3 h, compared to those of control plants (AR-pH 5.5 treated plants). Either water or Fe-EDTA (0.1 mM) was sprayed onto the leaves exposed to the AR-pH 2.5 treatment for 30 min at the fruit growth stage and seedling stage in order to alleviate the injury of the AR. The foliar-applied water prevented the development of leaf symptoms, growth reduction and yield loss at the fruit growth stage as well as at the seedling stages of the pepper plant. The stem dry weight, leaf dry weight, fruit fresh weight and fruit number of fruiting pepper plants applied with water increased by approximately 33, 34, 35 and 40% (P < 0.05) respectively, compared to those of the AR-pH 2.5 treated plants. The post-treatment of either water or Fe-EDTA resulted in no leaf symptoms in plants at both stages. The plant height, leaf area and leaf dry weight of pepper seedlings increased by approximately 7% (P < 0.05), 17% (P < 0.05), and 3% (P < 0.001) respectively, compared to the AR-pH 2.5 treated seedlings.
- 出版日期2010-10
