有棱丝瓜苗期耐热性及其对热胁迫的生理响应

Thermotolerance of Luffa acutangula Seedlings and Their Physiological Response to Heat Stress

摘要:

为鉴定有棱丝瓜（Luffa acutangula）的耐热性，对32个品种进行了耐热性筛选，并对不同耐热性品种在热胁迫下的生理响应进行了研究。结果表明，这些品种中有耐热品种3个，热敏品种4个，居中的25个。对耐热品种WB121，较耐热品种YL8和热敏品种WB105进行高温处理，结果表明，随着高温胁迫时间的延长，3个品种叶片的丙二醛含量、相对电导率、可溶性糖含量均逐渐增加。3种保护酶（SOD、CAT和POD）活性未表现出与耐热性一致的变化。3个品种的叶绿素荧光参数Fv/Fm、Yeild和ETR随着高温胁迫时间的延长均下降，以热敏品种下降幅度最大。Pearson相关分析表明，热害指数与相对电导率呈显著正相关（r=0.693^*），与丙二醛和可溶性糖含量呈极显著正相关（r=0.814， 0.899^**），与叶绿素荧光参数（Fv/Fm， Yield， ETR）呈极显著负相关（r=-0.892，-0.896，-0.897^**），与3种保护酶活性的相关性不显著。由此可见，叶绿素荧光参数（Fv/Fm， Yield， ETR）可以快速、准确地反映植物热害，建议将其作为有棱丝瓜耐热性鉴定的重要生理指标。

Abstract:

In order to identify the thermotolerance of Luffa acutangula,thirty-two varieties were screened,and the physiological response to heat stress with different heat resistance,such as WB121(tolerant),WB105(susceptible) and YL8(intermediate),was studied.The results showed that 32 luffa varieties included 3 heat-tolerant,4 heat-susceptible,and 25 intermediate varieties.The relative conductivity (RC),the contents of malondialdehyde (MDA) and soluble sugar (SC) in three varieties gradually increased with the prolongation of heat stress.However,there is no significant difference in activities of three antioxidases (SOD,CAT and POD) within these cultivars.The chlorophyll fluorescence parameters (Fv/Fm,Yeild and ETR) of all the three luffa varieties decreased with the time of heat stress,in which the susceptible variety WB105 had significant decline.The Pearson correlation analysis indicated that the heat injury index had positive correlation with RC,MDA and SC,but negative with the chlorophyll fluorescence parameters (Fv/Fm,Yeild and ETR),and the correlations between the heat injury index and three antioxidases (SOD,CAT and POD) activities were not significant.Therefore,the chlorophyll fluorescence parameters (Fv/Fm,Yeild and ETR) are rapid and accurate indicator of the heat injury and could serve as important physiological parameters for identification of thermotolrance in Luffa acutangula at the seedling stage.