香蕉冷害过程叶片抗坏血酸含量及过氧化氢酶活性的变化

CHANGES OF ASCORBIC ACID AND CATALASE ACTTVITYOF BANANA LEAVES DURING THE OCCURRENCEOFCHILING INJURY

在人工气候室中通过人工降温使香蕉及大蕉受低温胁迫。在气温降至１℃时香蕉植株出现冷害而大蕉植株仍生长正常。香蕉在冷害过程中，叶片中抗坏血酸含量明显下降。大蕉在低温胁迫过程中，叶片中的抗坏血酸含量一直高于香蕉且降幅很微。香蕉及大蕉的过氧化氢酶活性在温度从１０℃降至４℃时有增强的趋势，继续降温时则下降。但大蕉叶片中过氧化氢酶的活性在整个低温胁迫过程均高于香蕉。自然越冬过程田间大蕉叶片中抗坏血酸含量及过氧化氢酶活性均明显高于香蕉。本文对香蕉、大蕉的耐冷能力与抗坏血酸含量及过氧化氢酶活性的关系进行了讨论。

Potted banana(Musa AAA group CV. Dazhong Gaoba and Musa ABB group CV.Aiba Dajiao)plants suffered from low temperature stress caused by the artificial low-ering of temperature in the phytotron. Chilling injury occurred in AAA bananaplants when air temperature went down to 1℃,while ABB banana grew normallyunder this temperature.The ascorbic acid content of AAA banana leaves decreased ob-viously during the occurrence of chilling injury. The ascorbic content of ABB bananaleaves remained higher than that of AAA banana and decreased slightiy in the pro-eess of low temperature stress.Catalase activity in the leaves of both bananas in-creased when the temperature lowered from 10℃ to 4℃,and then decreased whenthe temperature lowered further。 But catalase activity in ABB banana leaves wereconsistently higher than that of AAA banana leaves in the whole process of lowtemperature stress. The contents of ascorbic acid and the activity of catalase offield─grown ABB banana were consistently higher than those of field─grown AAA banana during the winter.The correlation between chilling injuryresistance and the contents of ascorbic acid and the activity of catalase in AAA andABB banana were discussed.