低温诱导胁迫下不同烟草品种电导率及抗氧化酶活性的变化

Changes of antioxidant enzyme activity and conductivity of different tobacco varieties under low temperature induced stress

为筛选抗寒烟草品种,选择具有代表性的6种烟草品种为试材,研究了低温诱导胁迫下烟草叶片的相对电导率、半致死温度、抗氧化酶活性和丙二醛(MDA)含量等生理生化指标的变化规律。结果表明:随着低温胁迫的加剧相对电导率呈递增趋势,6种烟草的半致死温度由大到小依次为云烟87、NC95、建平大人头、吉烟九号、漂河一号和延晒七号;随着温度的下降抗氧化酶活性均呈先增长后下降的趋势,抗氧化酶活性增幅越大或降幅越低,则抗寒性越强,增幅由大到小依次是延晒七号、漂河一号、吉烟九号、建平大人头、NC95和云烟87;随着低温胁迫加剧MDA含量也呈先升高后下降趋势,且各烟草品种含量达到峰值的温度有所差异,其峰值越早或增幅越大,则抗寒性越弱。其中,云烟87在8℃时达到峰值且增长幅度最大,NC95和建平大人头均在6℃时达到峰值且增长幅度次之,而延晒7号、漂河1号和吉烟9号均较晚,在4℃时达到峰值,且增长幅度均较低。结合烟草叶片相对电导率、半致死温度、抗氧化酶活性和MDA含量生理生化指标的表现来看,延晒7号、漂河1号抗寒能力较强;吉烟9号、建平大人头抗寒性中等;云烟87和NC95抗寒能力较弱。

In order to screen cold-resistant tobacco varieties,the relative conductivity and semi-lethal temperature of tobacco leaves under low temperature induction stress,changes of physiological and biochemical indexes such as antioxidant enzyme activity and content of MDA were studied.The results showed that with the intensification of low temperature stress,the relative conductivity increased.The semi-lethal temperature of six kinds of tobacco was arranged in the order of Yunyan 87,NC95,Jianping adults,Jiyan No.9,Yanshai No.1 and Yanshai No.7.With the decrease of temperature,the activity of antioxidant enzymes increased first and then decreased.The larger or lower the increase in the activity of antioxidant enzymes,the stronger the cold resistance,and the higher the increase was from large to small.The MDA content ofXianghe No.1,Jiyan No.9,Jianping adults,NC95 and Yunyan 87 also increased first and then decreased with the increase of low temperature stress,and the temperature of each tobacco variety reached the peak value,and the earlier the peak value or the greater the increase.The cold resistance of Yunyan 87 reached its peak at 8℃,and the increase amplitude of NC95 and Jianping adult head reached its peak value at 6℃,and the increase range was the second,while Yanshai 7,drifter river 1 and Jiyan 9 were all late.In combination with the relative electrical conductivity,semi-lethal temperature,antioxidant enzyme activity and physiological and biochemical indexes of MDA content in tobacco leaves,Yanshai No.7 and Piaohe No.1 had stronger resistance to cold,Jiyan No.9 and Jianping adult head had medimum cold resistance to cold,Yunyan 87 and NC95 had weaker cold resistance.