减弱UV-B辐射对烟草(Nicotiana tabacum L.)叶片SOD、POD和CAT活性动态变化影响初探

Effects of UV-B radiation on SOD,POD and CAT activity in tobacco(Nicotiana tabacum L.) leaves

以云南种植面积较广的烟草品种K326作为供试材料进行盆栽种植,选择云南烟叶主产的玉溪烟区种植烤烟海拔最高的通海县(1806米)为试验点,通过在自然条件分别减弱25%(T1)、50%(T2)和65%(T3)的太阳UV-B辐射,研究同一种植地不同UV-B辐射对烤烟中部叶片发育过程中SOD、POD和CAT活性动态变化的影响。结果表明:T1和T3处理对烤烟SOD活性没有大的影响,但能减轻叶片衰老时的氧化胁迫,而T2处理虽能使烟叶SOD活性在7月22日之前维持稳定的且较低的水平,但之后SOD活性波动较大且高;减弱UV-B辐射没有改变烟叶生长过程中POD活性的上升趋势,但T1和T2处理在8月1日之前稍降低了POD活性,T2处理提高了8月1日～8月15日时段烟叶POD活性,而T3处理的该时段烟叶POD活性不变;减弱UV-B辐射对CAT的活性没有影响。结果说明3种酶中SOD和POD相对较UV-B辐射敏感,在降低75%～80%全光照条件下,烤烟有较宽的低UV-B辐射耐受范围。

Tobacco variety K326 which is widely grown in Yunnan province was used in pot experiment to investigate effects of different levels of UV-B radiation on SOD,POD and CAT activities in middle tobacco leaves. The experiment was carried out in Tonghai county where altitude is the highest （1 806 m） in Yuxi tobacco grow region. Different UV-B levels reduced by 25% （T1）,50% （T2） and 65% （T3） were created. No significant change was observed in SOD activity in T1 and T3 treatments compared with control,but increased in old leaves. T2 treatment resulted in stablized SOD activity in lower level before 22nd July,and thereafter fluctuated to become higher. Reduced UV-B radiation did not change the increasing trend of POD activity during leaf growth. However,T1 and T2 treatments reduced POD activity before 1st August,and T2 treatment increased activity from 1st August to 15th August,while it remained the same in T3 treatment. Reduced UV-B radiation showed no effect on CAT activity while SOD and POD activity were relatively sensitive to UV-B. In 75%～80% reduced entire illuminations conditions,variety K326 can tolerate a wide range of low UV-B radiation.