基于光合特性评价10个杜鹃花品种的耐热能力

Evaluation of heat resistance of azalea based on photosynthetic characteristics

为了探讨不同杜鹃花品种的耐热性差异,以10个杜鹃花品种2年生扦插苗为材料,对其在人工模拟高温胁迫下叶片的光合特效进行测定,并运用主成分分析法和隶属函数法进行综合评价。结果表明,在高温胁迫下,10个杜鹃花品种的净光合速率、蒸腾速率、气孔导度等共6个光合指标均呈下降趋势,且不同品种的下降幅度不同;利用主成分分析将原来的Pn,Tr,Gs,Ci,WUE,LUE,CUE,Ls共8个相互关联的光合指标转化为4个独立的主成分,其累计贡献率达94.5937%,由这4个主成分的特征向量表达式可知,在第1个主成分中,LUE,CUE占主导作用,在第2个主成分中Tr,Gs占主导作用,在第2,4个主成分中占主导作用的分别是WUE和Gs。并通过隶属函数及其权重,计算得到综合评价值(D值),将10个杜鹃花品种按照耐热性的强弱划分为3类:‘炮仗红’‘石岩杜鹃’‘胭脂蜜’属于强耐热类型,‘晓霞’‘丰美1号’‘媱妃’‘春樱’属于中等耐热类型,‘紫金粉玉’‘小莺’‘粉红泡泡’属于不耐热类型。

In order to explore the differences in heat resistance of different azaleas,the photosynthetic characteristics of 2-year cuttings of 10 azalea cultivars under artificial high temperature stress were measured,and the principal component analysis and membership function method were used for comprehensive evaluation.The results showed that under high temperature stress,the net photosynthetic rate,transpiration rate,stomatal conductance and the other there photosynthetic indexes of 10 azalea cultivars all decreased,and the decrease rates were different among different cultivars.Such eight original correlative photosynthetic indicators as the net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),intercellular CO2 concentration(Ci),water use efficiency(WUE),light use efficiency(LUE),CO2 use efficiency(CUE)and limiting value of stomata(Ls)could be transformed into four independent principal components by using principal component analysis,with the cumulative contribution rate up to 94.593%.According to the eigenvector expressions of these four principal components,LUE and CUE played a dominant role in the first principal component,Tr and Gs played a dominant role in the second principal component while WUE and Gs played a dominant role in the third and fourth principal components respectively.Moreover,the comprehensive evaluation value(D value)was calculated by membership function and its weight.According to the above results of the heat resistance,these 10 azalea cultivars were divided into three categories:‘Paozhanghong’,‘Shiyandujuan’and‘Yanzhimi’belonged to high heat-tolerance type;‘Xiaoxia’,‘Fengmeiyihao’,‘Yaofei’and‘Chunying’belonged to medium heat-tolerance type;‘Zijinfenyu’,‘Xiaoying’and‘Fenhongpaopao’belonged to poor heat-tolerance type.