火龙果幼苗对低温胁迫的生理响应及其抗寒性综合评价

Physiological Responses of Pitaya(Hylocereus spp.) Seedlings to Chilling Stress and Comprehensive Evaluation of Their Cold Resistance

以野生火龙果量天尺和贵州主栽品种‘紫红龙’、‘晶红龙’、‘粉红龙’扦插幼苗为试材,人工控温进行抗寒锻炼、低温冷害处理及恢复生长,以未处理作对照,测定不同处理下幼苗的电解质渗出率(REC)、可溶性糖、可溶性蛋白、游离脯氨酸和丙二醛(MDA)含量的变化。结果表明,电解质渗出率随温度降低逐渐增加,恢复生长后电解质渗出率与对照之间没有显著差别。幼苗中的可溶性糖、可溶性蛋白、脯氨酸及丙二醛含量在抗寒锻炼和低温处理后升高,恢复生长后降低。可溶性糖和脯氨酸含量随不同处理变幅较大,MDA和可溶性蛋白随不同处理变幅较小。运用Fuzzy数学中隶属函数法进行抗寒性综合评价,得出火龙果抗寒性强弱表现为量天尺>‘晶红龙’>‘粉红龙’>‘紫红龙’,与恢复生长的试验结果基本一致。

The dynamic changes of relative electric conductivity （REC）, soluble sugar, soluble protein, proline and malonadehyde （MDA） in cold acclimation, chilling stress and recovery growth were investigated using the pitaya cutting seedlings of a wild type （Hylocereus undatus Liangtianchi） and three main cultivars （Hylocereus polyrhizus ＇Zihonglong＇, Hylocereus undatus ＇Jinghonglong＇, Hylocereus monacanthus ＇Fenhonglong＇）. The results indicated that REC increased with the temperature decrease, and there was no significant difference between contrast and recovery growth experiment. The contents of soluble sugar, soluble protein, proline and MDA increased in low temperature treatment and decreased in recovery growth in all materials. Furthermore, the variation of soluble sugar and proline contents were remarkable with different treatments, but MDA and soluble protein contents had no apparent changes in the whole processes. By using fuzzy mathematics method, the cold resistance of these pitaya cultivars were evaluated as Liangtianchi〉＇Jinghonglong＇〉 ＇Fenhonglong＇〉＇Zihonglong＇, which was in agreement with the results of recovery growth experiment.