苦瓜耐低钾性生理生化指标评估体系的构建

Evaluation system construction of physiological and biochemical indexes of low potassium tolerance of balsam pear

  • 摘要: 【目的】探讨苦瓜种质资源耐低钾胁迫的鉴定方法,为培育耐低钾丰产优质苦瓜品种提供种质资源。【方法】以11份苦瓜种质为材料,设置低钾(K+浓度0.2 mmol/L)和正常钾(K+浓度4.0 mmol/L)处理,采用多元统计的方法综合分析低钾胁迫下的苦瓜种质的各项生长及生理指标。【结果】苦瓜种质的株高、茎粗、节间长、叶面积、地下部干重、地上部干重、根长、根表面积、根体积、叶绿素a、叶绿素b、类胡萝卜素、总叶绿素、丙二醛和钾累积量等15个鉴定指标的变异幅度较大,变异系数均超过10.0%。利用主成分分析将15个鉴定指标的胁迫系数经过标准化(Z-score法)后进行降维处理,从所有的因子中聚焦为4个主成分,共解释总变异的83.690%。根据4个主成分得分计算隶属函数值最终确定综合指标(D值),采用聚类分析方法将11份种质分为4类,第Ⅰ类的04-25、1717、KG01-2和03-8为耐低钾种质,第Ⅱ类的1721、11-8、DD14-1、04-17-4和26-2为中等耐低钾种质,第Ⅲ类的06-16为低钾弱敏感种质,第Ⅳ类的25-15为低钾敏感种质。通过多元回归分析法建立最优的综合评价数学模型: Y=0.768×株高+0.443×钾累积量+0.390×根表面积+0.595×叶绿素a-0.415。【结论】11份苦瓜种质中04-25为最耐低钾种质,株高、钾累积量、根表面积和叶绿素a可作为苦瓜种质耐低钾性评价指标,该评价体系可用于苦瓜种质耐低钾性的快速筛选。

     

    Abstract: 【Objective】The purpose of the study was to explore the identification of balsam pear germplasm resources that were resistant to low potassium stress,and to provide germplasm resources for cultivating high-yield and high-quality balsam pear varieties with low potassium tolerance.【Method】Eleven balsam pear germplasms were used as materials, and two treatments of low potassium(K+ concentration of 0.2 mmol/L)and normal potassium(K+ concentration of 4.0 mmol/L)were set up. The growth and physiological indexes of balsam pear germplasms under low potassium stress were comprehensively analyzed by multivariate statistical method. 【Result】The variation of 15 identification indexesof balsam pear germplasm,including plant height,stem diameter,internode length,leaf area,underground dry weight,above ground dry weight,root length,root surface area,root volume,chlorophyll a,chlorophyll b,carotenoid,total chlorophyll, malondialdehyde and potassium accumulation was large, with the coefficients of variation exceeding 10.0%. Principal component analysis was used to standardize the stress coefficients of 15 identification indexes (Z-score method) and reduce the dimensionality of the coefficients. From all the factors,the stress coefficients were focused into 4 principal components,which accounted for 83.690% of the total variation. According to the scores of the four principal components, the membership function values were calculated and comprehensive index(D value)was finally determined. The 11 germplasms were divided into four categories by cluster analysis method. The germplasms 04-25,1717,KG01-2 and 03-8 in class Ⅰwere low potassium tolerant,the germplasms 1721,11-8,DD14-1,04-17-4 and 26-2 in class II were medium low potassium tolerant,the germplasm 06-16 in class IIIwere low potassium weakly sensitive,and the germplasm 25-15 in class III were low potassium sensitive. The optimal comprehensive evaluation mathematical model was established by multiple regression analysis: Y=0.768×plant height+0.443×potassium accumulation+0.390×root surface area+0.595×chlorophyll a -0.415.【Conclusion】Among the 11 balsam pear germplasms,04-25 is the most lowpotassium tolerant germplasm. Plant height,potassium accumulation,root surface area and chlorophyll a can be used as the evaluation indexes for the low potassium tolerance of balsam pear germplasm. The evaluation system can be used for the rapid screening of the low potassium tolerance of balsam pear germplasm.

     

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