‘玉霞’含笑与其亲本抗寒生理特性比较

Comparison of physiological characteristics of cold resistance between Michelia ‘Yuxia’ and its parents

通过测定人工低温胁迫下叶片生理指标和常温下叶片解剖结构指标,比较研究‘玉霞’含笑(Michelia‘Yuxia’)及其亲本醉香含笑(M.macclurei)和云南含笑(M.yunnanensis)的抗寒性强弱,结果表明:人工低温胁迫下,3种含笑的半致死温度(LT50)范围为-14.362^-8.881℃;随着胁迫温度的降低,丙二醛含量和相对电导率呈现逐渐上升的趋势,超氧化物歧化酶活性和可溶性蛋白含量呈现先上升后下降的趋势;聚类分析表明,角质层厚度、叶片厚度和栅海比3个指标能较好地反映植物的抗寒性。综合LT50和各指标隶属函数分析,得出3个树种的抗寒性强弱排序为:醉香含笑>云南含笑>‘玉霞’含笑。

By measuring the physiological indexes of leaves under artificial low temperature and the anatomical indexes of leaves under normal temperature,the cold resistance of Michelia‘Yuxia’and its parents,M.macclurei and M.yunnanensis,were comprehensively compared.The results show that under artificial low temperature stress,semi-lethal temperature(LT50)of three Michelia varieties was between-14.362 and-8.881℃.With the decrease of stress temperature,relative electric conductivity(Rec)and the content of malondialdehyde(MDA)increased;the superoxide dismutase(SOD)activity and soluble protein content increased firstly,and then decreased.Cluster analysis showed that the three factors of cuticle layer thickness,leaf thickness and ratio between palisade tissue and spongy tissue could better reflect the cold resistance of plants.Based on the LT50 and the membership function analysis of each indicator,the cold resistance of three Michelia varieties was ranked as M.macclurei>M.yunnanensis>M.‘Yuxia’.