高温、强光对苹果树冠不同方位果皮的氧化胁迫研究

Effects of High Temperature and Strong Light on Oxidative Stress of Apple Fruit Peel on Different Exposures of Tree Crown

自然条件下,树冠不同方位果实抗氧化胁迫能力有很大差异。树冠西南面最易发生高温和强光胁迫。生长季晴天树冠西南面果实接受的日最大光照强度比其它4个方位(东北、东、北、西北)高600～1260μmol穖-2穝-1,果面日最高温度比其它4个方位高5～6.5℃。一般在中度高温强光胁迫条件下,处于树冠西南方位外围充分暴露的果实,其表皮组织中超氧物自由基和MDA含量以及SOD和POD活性都高于其它方位。果实日灼症状出现前后,表皮组织中SOD和POD活性变化趋势不同,可能与其作用位点及对高温的抗性差异有关。

Under natural conditions, there was a considerable difference in resistance to oxidative stress among fruist on different exposures on a canopy. The high temperature and strong light stress frequently happen on the southwest exposure. In a clear and sunny day, the light intensity received by the fruit on southwest canopy was 600-1260μmol穖-2穝-1 more than those from northeast, east, north and northwest exposures, and the maximum fruit surface temperature was 5-6.5℃ higher than other direction exposures. Under medium temperature stress, the contents of O2-. and MDA as well as the activities of SOD and POD in the fruit peel on southwest canopy were significantly higher than those from other exposures. A difference of enzymatic activity with SOD and POD was documented at different stages of fruit sunburn, which might be related to the tolerance of POD to heat stress and its particular function.