低温弱光对甜椒幼苗生长和生理生化指标的影响及其与品种耐性的关系

Effects of Low Temperature and Weak Light on the Growth and Physiological and Biochemical Indexes of Sweet Pepper Seedlings and Their Relationship to Varieties Tolerance

以甜椒品种‘P12101’(低温弱光敏感品种)和‘夏寒帝’(耐低温弱光品种)为试材,在光照培养箱中采用常规基质培养法,研究了低温弱光条件下甜椒生长指标、叶绿素含量、叶绿素荧光参数、相对电导率、丙二醛(MDA)含量以及超氧化物歧化酶(SOD)活性在不同处理天数下的变化,以期探讨甜椒耐低温弱光胁迫的生理机制和生理生化指标。结果表明:1)低温弱光胁迫下,甜椒幼苗的生长受到抑制,2个品种的株高、茎粗、地上鲜质量、地下鲜质量均呈下降趋势,‘P12101’的各生长指标下降幅度显著高于‘夏寒帝’;2个品种的叶绿素含量在低温弱光条件下也表现出下降趋势,其中‘P12101’显著低于‘夏寒帝’。2)2个甜椒品种在低温弱光处理下其叶绿色荧光参数Fo和Fv/Fm差异不显著,而Y(Ⅱ)在处理10d,Y(NPQ)和Y(NO)在处理15d2个品种表现出显著性差异。这表明虽然耐低温弱光品种在光能捕获吸收上同低温弱光敏感品种差异性不显著,但其在光能调节和利用上比后者更加有效。3)2个品种的MDA含量和相对电导率在低温弱光处理期间均呈逐渐升高趋势,并且‘P12101’显著高于‘夏寒帝’;4)低温弱光导致2个品种的SOD活性均呈先降后升趋势,处理15d后,2个品种表现出显著性差异。对于甜椒品种耐低温弱光鉴定上,以处理15d为宜,生长指标、叶绿素含量、电导率、MDA含量、叶绿素荧光参数Y(Ⅱ)、Y(NPQ)和Y(NO)均可作为甜椒耐低温弱光鉴定指标,其中叶绿素荧光参数Y(Ⅱ)、Y(NPQ)和Y(NO)较合适。

To elucidate the physiological mechanism of tolerance and the physiological and biochemical indexes of sweet pepper to low temperature and weak light stress,the growth indicators,chlorophyll contents,chlorophyll fluorescence parameters,relative conductivities,malondialdehyde(MDA)content and the change of superoxide dismutase(SOD)activities in different treatment days were studied in two kinds of sweet pepper,’P12101’(a low temperature and weak light sensitive variety)and’Xiahandi’(a low temperature and weak light resistant variety)by using the conventional medium culture method in the light incubator.The results showed that,1)the growth of sweet pepper seedings was inhibited under low temperature and weak light stress,the plant height,stem diameter,fresh shoot weight and fresh root weight of two varieties showed a downward trend.Compared to’Xiahandi’,the decline range of each growth index of’P12101’was significantly higher.The content of chlorophyll of the two varieties also showed a downward trend under low temperature and low light,of which’P12101’was significantly lower than that of’Xiahandi’.2)Chlorophyll fluorescence parameters Fo and Fv/Fm of two sweet pepper varieties had no significant difference under low temperature and week light stress.Y(Ⅱ)showed remarkable difference after 10 days′treatment,and Y(NPQ)and Y(NO)showed remarkable differences after 15 days′treatment.This indicated that although there was no significant difference in optical energy capture and absorption between the low temperature and weak light resistant variety and the low temperature and weak light sensitive variety,the low temperature and weak light resistant variety was more effective in light energy regulation and utilization than the latter.3)MDA content and relative conductivities of the two varieties increased gradually during low temperature and week light treatment,and’P12101’was significantly higher than’Xiahandi’.4)SOD activities of the two varieties decreased firstly and then increased due to low temperature and weak light treatment.After 15 days′treatment,two varieties showed significant difference.The above results indicated that 15 days of treatment was the best time for identification of low temperature and weak light tolerance of sweet pepper varieties.Growth index,chlorophyll content,relative conductivity,MDA content,chlorophyll fluorescence parameters Y(Ⅱ),Y(NPQ)and Y(NO)could be used as identification indexes of low temperature and weak light tolerance of sweet pepper,and among them,chlorophyll fluorescence parameters Y(Ⅱ),Y(NPQ)and Y(NO)were more suitable.