低温处理对云南含笑幼苗生理特性的影响

Effect of Low Temperature on Physiological Traits of Michelia yunnanensis Seedlings

本研究选择云南含笑半年生实生苗为材料,对其进行人工低温处理,共设4个处理组[25(对照)、15、5、0℃],研究其部分生理生化特性对不同程度低温处理的响应差异。结果表明,15℃的低温条件对该树种的影响较小,各项生理指标变化不显著;5℃低温下,叶绿素b含量显著减少,抗氧化酶SOD、APX活性显著增加,抑制了细胞的膜脂过氧化,脯氨酸含量显著增加,说明该树种可以通过自身的积极响应来减轻低温伤害;而0℃低温胁迫对该树种造成的伤害较大,可溶性蛋白含量、叶绿素a及叶绿素b含量都显著下降,膜脂过氧化严重。试验结果说明云南含笑可以抵抗一定程度的低温,但随着温度的进一步降低,该树种的正常生理代谢及生长发育会受到严重影响。

In this study,the half-year old seedlings of Michelia yunnanensis were used as experiment materials,which were determined for some physiological traits by low temperature with four treatments [25（CK）,15,5,0 ℃].The results showed that the physiological indexes were not significantly affected by 15 ℃ treatment.While under the 5 ℃treatment,the content of chlorophyll b was reduced,and the superoxide dismutase（SOD） and the ascorbic acid peroxidase（APX） activities were improved to release the free radicals.In addition,the proline was accumulated,which suggested the Michelia yunnanensis seedlings could alleviate the low temperature damage through it＇s positive responses.The 0 ℃ treatment could cause more serious damage in the Michelia yunnanensis seedlings,and the soluble protein,chlorophyll a and chlorophyll b contents,and high MDA content were significantly decreased.This study suggested that the Michelia yunnanensis plants could resist low temperature stress in a certain degree,while the further low temperature might seriously influence the normal physiology and metabolism,even the growth and development of plants.