两种常绿杜鹃亚属幼苗耐热性的主成分及隶属函数分析

Analysis of Principal Components and Subordinate Function on Heat Tolerance of Two Seedlings of Rhododendron Subgenus Hymenanthes

摘要:

以常绿杜鹃亚属(Rhododendron subgenus Hymenanthes)的井冈山杜鹃(R. jinggangshanicum Tam)、猴头杜鹃(R. simiarum Hance) 4年生实生苗为材料,在人工气候箱中模拟高温试验,测定不同温度下叶片的丙二醛(MDA)、过氧化氢(H₂O₂)、脯氨酸(Pro)、可溶性蛋白质、抗坏血酸(AsA)含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)及抗坏血酸过氧化物酶(APX)活性等生理生化指标,并采用主成分分析与隶属函数相结合的方法对其种间耐热性进行综合评价。结果表明,与杜鹃幼苗耐热性密切相关的生理生化指标有MDA、H₂O₂、SOD、CAT、POD及APX,6个指标的隶属函数值(U值)与所有指标的U值高度相关(r=0.987^**),达到了极显著水平;在30℃和38℃高温条件下,猴头杜鹃的U值及其增幅均大于井冈山杜鹃,评价结果与其田间耐热性一致。因此,本方法可用来对该亚属杜鹃幼苗的种间耐热性进行客观评价。

Abstract:

In order to explore the indices and evaluation method of heat tolerance of Rhododendron subgenus Hymenanthes, 4-year-old seedlings of R. jinggangshanicum Tam and R. simiarum Hance were planted in artificial climate chamber under different high temperatures (30℃, 38℃, and with 22℃ as control). The contents of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), proline (Pro), soluble protein, ascorbic acid (AsA) and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) were determined after treated for 6 days. The heat tolerance of two species was comprehensively evaluated by principal components analysis and fuzzy subordinate function based on the measurement values of tested parameters. The results showed that MDA, H₂O₂, SOD, CAT, POD, APX were the most important physiological and biochemical indexes for heat tolerance of Rhododendron seedlings. A very significant correlation (r=0.987^**) was found between the subordinate function values (U value) of 6 main indices and U value of whole indices. The U value and increased range of U value in R. simiarum were larger than those in R. jinggangshanicum at 30℃ and 38℃, the evaluation results accorded with their behavior in the field. It is suggested that the method can give an objective evaluation on the comprehensive heat tolerance between different species of Rhododendron subgenus Hymenanthes seedlings.