低温处理对北美冬青叶片抗氧化能力的影响

Effect of Low Temperature Stress on Antioxidant Ability in Ilex verticillata Leaves

摘要:

为了解低温对北美冬青（Ilex verticillata）生长的影响，对2年生扦插苗经低温处理（-6℃）后的生长和抗氧化能力进行了研究。结果表明，随着低温处理时间的延长，北美冬青叶片的叶绿素/类胡萝卜素比值和叶绿素b含量增加，而其他色素含量都呈下降趋势；相对电导率（REC）和H₂O₂含量（72 h除外）显著增加。低温处理对超氧化物歧化酶（SOD）活性影响不大，却显著降低CAT的活性。低温处理过氧化物酶（POD）活性显著提高，48 h活性达到最高；而抗坏血酸过氧化物酶（APX）活性在处理12 h达最高，然后下降。还原型抗坏血酸（AsA）、还原型谷胱甘肽（GSH）含量均呈先升高再下降的趋势。因此，北美冬青在短时间内（≤24 h）能够忍受低温（-6℃），抗氧化防御系统在低温初期起关键的作用，但随时间延长（72 h）其抗氧化能力减弱。

Abstract:

In order to understand the effect of low temperature on growth of Ilex verticillata, the photosynthetic pigment contents, antioxidant enzymes activities and antioxidant ability of 2-year-old seedlings under -6℃ were studied. The results showed that the chlorophyll, carotenoids contents in leaves decreased, while the ratio of chlorophyll/carotenoids and chlorophyll b content increased under low temperature. The REC (relative electrical conductivity) and H₂O₂ content significantly increased under low temperature. There was no significant difference in superoxide dismutase (SOD) activity, but the catalase (CAT) activity significantly reduced. Under low temperature, the peroxidase (POD) activity significantly increased, and reached the peak treated for 48 h. The ascorbate peroxidase (APX) activity enhanced treated for 12 h, and then decreased. The AsA (ascorbic acid) and GSH (glutathione) contents increased at first 24 h then decreased from 48 to 72 h. Therefore, Ilex verticillata seedlings could endure low temperature stress for short term (12-24 h), and antioxidant system could play key role in cold stress at early stage, but it might suffer damage with time extension under low temperature.