低温胁迫下不同甘蔗品种(系)光合特性的变化及其与耐寒性的关系

以广西农科院甘蔗研究所自育的7个新材料和2个生产上的主栽品种为研究对象,在甘蔗苗期进行低温胁迫处理,研究了各品种(系)甘蔗形态特征的冷害指数、叶绿素含量及光合特性相关指标的变化及其光合特性相关指标与甘蔗抗寒性间的相关性。结果表明:随着低温胁迫处理时间的延长,冷害指数不断增大,但变化的大小与快慢因品种(系)不同表现不一样。各甘蔗品种(系)叶片叶绿素含量均随时间延长而降低。叶片净光合速率、气孔导度在低温处理与常温处理间具有显著差异。低温胁迫处理显著降低了各甘蔗品种(系)最大光化学效率(Fv/Fm)、PSⅡ实际光能转化效率ΦPSⅡ、光适应下PSⅡ反应中心的最大光能转化效率Fv′/Fm′、光化学猝灭系数qP、电子传递速率ETR,而显著提高了初始荧光Fo、稳态荧光Fs、非光化学猝灭系数qNP。相关性分析表明整个测定时期各指标间相关显著,Fv/Fm、Fv′/Fm′、ΦPSⅡ与冷害指数I之间的相关系数在0.800以上,Fv/Fm、Fv′/Fm′、ΦPSⅡ可以作为甘蔗品种(系)抗寒性鉴定的重要参考指标。

Correlation between changes of photosynthetic characteristics of different sugarcane varieties and their cold tolerance under low temperature

In order to explore the correlations between changes of photosynthetic characteristics and cold tolerance in different sugarcane varieties , 7newly bred sugarcane lines and 2main cultivars from Sugarcane Research Institute , Guangxi Academy of Agricultural Sciences were employed to examine the changes of chilling injury index , chlorophyllcontent and photosynthetic perameters under low temperature stress at seedling stage.The chilling injury index was continually increased with the prolonging of low temperature treatment , but different sugarcane varieties showed different changes.The chlorophyll content in all the sugarcane varieties were continually decreased with the prolonging of low temperature treatment.There were significant differences in net photosynthetic rate and stomatal conductance between room temperature treatment and low-temperature treatment.The Fv / Fm , ΦPSⅡ , Fv′ / Fm′ , qPand ETR were decreased obviously , but Fo , Fs and qNP were increased after the low temperature treatment.There were significant correlations between chlorophyll content , various photosynthetic perameters and chilling injury indexes , and the correlation coefficients between Fv / Fm , Fv′ / Fm′ , ΦPSⅡand chilling injury indexes were higher than 0.800 , which suggested that Fv / Fm , Fv′ / Fm′ , ΦPSⅡcould be used as the indexes of cold tolerance identification in sugarcane.