基于主成分–聚类–逐步回归分析构建番茄苗期耐铝性综合评价体系

Establishment of a Comprehensive Evaluation System for Aluminum Tolerance in Tomato Seedlings Based on Principal Component Analysis–Clustering Analysis–Stepwise Regression Analysis

铝毒是限制酸性土壤中作物产量的主要因素之一。番茄(Solanum lycopersicum)是适合在酸性土壤中种植的主要经济作物,不同品种番茄对铝胁迫的响应存在差异,因此,筛选苗期耐铝毒种质对番茄生产及研究具有重要意义。以10个番茄品种为材料,采用室内土培盆栽,设置1 000μmol·L^(-1)AlCl_(3)·6H_(2)O处理,测定反映植物铝胁迫下生长状况的16个形态、生理生化及光合指标。通过主成分分析,将铝胁迫下番茄幼苗的16个指标转化为5个独立的综合指标,累积贡献率达90.779%。基于耐铝性综合评价值(A)的系统聚类分析,将供试种质划分为5类,第Ⅰ类为高度耐铝品种Qianxi,第Ⅴ类为高度不耐铝品种Puluowangsi。经多元线性逐步回归分析得出番茄苗期耐铝评价方程:y=0.046+0.405X_(6)+0.515X_(10)–0.207X_(15)+0.028X_(3)(R~2=0.997),从16个指标中提取出与A值显著相关(P<0.01)的4个指标:丙二醛含量(X_(3))、净光合速率(X_(6))、叶面积(X)和地下部干重(X_(6))。利用评价方程可判断不同番茄品种苗期的耐铝性,使番茄耐铝性鉴定工作快速简便。

Aluminum toxicity is one of the major factors limiting crop production in acid soils. Tomato is a dominant economic crop in acid soil and different varieties of tomato have different responses to aluminum stress. Therefore, screening aluminum tolerant seedling is of great significance for tomato production and research. In this study, 10 tomato varieties were used as materials, which were cultured indoor in pots containing soil, treated with 1 000μmol·L^(-1)AlCl_(3)·6H_(2)O. 16 morphological, physiological, biochemical or photosynthetic indicators reflecting the growth of plants under aluminum stress were determined. Through principal component analysis, 16 indicators of tomato seedlings under aluminum stress were converted into 5 independent comprehensive indicators, with a cumulative contribution rate of 90.779%. Based on the systematic cluster analysis of aluminum resistance value(A), the test germplasms were divided into five levels,category Ⅰ is a highly aluminum-tolerant variety, Qianxi, and category Ⅴ was a highly aluminum-intolerant variety, Puluowangsi. According to the multiple linear regression analysis, 4 of the 16 indicators were found to be significantly correlated with the A value(P<0.01): malondialdehyde content(X), net photosynthetic rate(X), leaf area(X) and dry weight of underground(X), with the following evaluation equation: y=0.046+0.405X_(6)+0.515X_(10)-0.207X_(15)+0.028X_(3)(R~2=0.997). The evaluation equation can be used to judge the aluminum toxicity resistance characteristics of different tomato varieties in seedling stage, which made the identification of tomato aluminum tolerance quick and simplified.