花椰菜叶绿素荧光参数与耐寒性的关系研究

以7个不同基因型花椰菜品种为材料，研究了低温胁迫对不同熟性和相同熟性花椰菜生长指标、冻害指数和叶绿素荧光参数的影响，以及相同熟性花椰菜冻害前后叶绿素荧光参数的变化，分析了花椰菜生长、耐寒性和叶绿素荧光参数的相关性。结果表明：低温胁迫下，冻害指数和叶绿素荧光参数中的初始荧光（Fo）仅在不同熟性的品种间具有显著差异，花球质量、植株营养体质量以及叶绿素相对含量（SPAD）和叶绿素荧光参数中的原初光能转化效率（Fv/Fm）在不同熟性和相同熟性的品种间均具有显著差异。相同熟性品种间在冻害前后Fv/Fm值均有显著差异。对不同基因型的生长指标、冻害指数和叶绿素荧光参数间的相关分析表明，直接反映花椰菜耐寒性的冻害指数与SPAD值和叶绿素荧光参数Fv/Fm值均显著负相关；间接反映花椰菜耐寒性的生长指标花球质量和营养体质量与叶绿素荧光参数Fv/Fm值显著正相关，而生长指标与SPAD值仅在不同熟性花椰菜间显著正相关。光化学转化效率与花椰菜的耐寒性紧密相关，叶绿素荧光参数Fv/Fm值可能为不同基因型间花椰菜耐寒性的鉴定指标。

Studies on the Relationship Between Chlorophyll Fluorescence Parameters and Cold Tolerance of Cauliflower

The effects of cold stress on growth index，freezing injury index and chlorophyll fluorescence parameters in seven different genotype cauliflowers with different or same maturity were studied. The changes of chlorophyll fluorescence parameters in different genotype cauliflowers with same maturity under freezing injury stress were also examined. The correlations among growth，cold tolerance and chlorophyll fluorescence parameters were analyzed in cauliflower varieties with different or same maturity. The results showed that there were significant differences among the varieties with different maturity in freezing injury index and minimal fluorescence（Fo），and there were significant differences among the varieties with the same and different maturity in head weight，vegetative mass weight，SPAD value and conversion efficiency of primary light energy（Fv/Fm）. Significant differences existed among the varieties with same maturity under freezing injury stress. Correlation analysis of growth index，freezing injury index and chlorophyll fluorescence parameters in different genotype varieties showed that freezing injury index which directly reflects cold tolerance were negatively correlated with SPAD and Fv/Fm. Head weight and vegetative mass weight which indirectly but externally reflects cold tolerance，were positively correlated with Fv/Fm in varieties with both same and different maturity，and positively correlated with SPAD only in varieties with different maturity. In conclusion，conversion efficiency of primary light energy closely related to cold tolerance，Fv/Fm could be used as index of cold tolerance identification in cauliflowers with both same and different maturity.