低温胁迫下八个澳洲坚果品种的抗寒性综合评价

Comprehensive evaluation of cold resistance of eightmacadamia varieties under low temperature stress

关键词:  澳洲坚果, 低温胁迫, 生理指标, 叶片形态, 抗寒性, 综合评价

Key words:  macadamia(Macadamia spp.), low temperature stress, physiological indices, leaf morphology cold resistance, comprehensive evaluation

摘要:

为了解澳洲坚果抗寒性强弱,选育抗寒性强的澳洲坚果品种,该研究采用-8 ℃低温胁迫8个广西澳洲坚果主要栽培品种的枝条,测定其叶片超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、可溶性糖(SS)含量、可溶性蛋白(SP)含量、脯氨酸(Pro)含量、丙二醛(MDA)含量、相对电导率(REC)和叶绿素(Chl)含量等抗寒性生理指标,运用相关性分析、主成分分析、隶属函数分析和聚类分析等方法,综合评价澳洲坚果抗寒性强弱。结果表明:(1)低温胁迫下10个抗寒性生理指标差异显著。(2)通过主成分分析可将10个生理指标转化为3个新生理指标,累计贡献率达90.194%; 结合相关性分析结果,筛选出SOD、POD、SS、SP、Pro、Chlb和Chl(a+b)作为澳洲坚果抗寒性鉴定的主要生理指标。(3)结合聚类分析结果和综合抗寒能力D值,可将8个澳洲坚果品种按照抗寒能力强弱划分为3类:第Ⅰ类抗寒性强,包括‘桂热引4号'‘桂热7号'‘HY'和‘JW'; 第Ⅱ类抗寒性中等,包括‘桂热5号'和‘桂热1号'; 第Ⅲ类抗寒性弱,包括‘A16'和‘桂热6号'。其中,‘桂热引4号'抗寒性最强; 而‘桂热6号'抗寒性最弱。低温胁迫后的叶片形态观察结果与聚类分析结果相一致。该研究为澳洲坚果的抗寒性研究提供了理论基础,并且对澳洲坚果在广西寒区种植及北移种植具有重要意义。

Abstract:

In order to assess the cold resistence of macadamia and select varieties with strong cold resistance. In this study, eight main cultivated varieties of macadamia in Guangxi were treated at -8 ℃ to determine physiological indices related to cold resistance, including superoxide dismutase(SOD)activity, peroxidase(POD)activity, soluble sugar(SS)content, soluble protein(SP)content, proline(Pro)content, malondialdehyde(MDA)content, relative electric conductivity(REC)and chlorophyll(Chl)content. The cold resistance of macadamia was comprehensively evaluated by correlation analysis, principal component analysis, membership function analysis and cluster analysis. The results were as follows:(1)A total of 10 physiological indices of cold resistance were significantly different under low temperature stress.(2)By principal component analysis, 10 physiological indices were converted into three new physiological indices, with a cumulative contribution rate of 90.194%. Combined with the correlation analysis results, SOD, POD, SS, SP, Pro, Chlb and Chl(a+b)were selected as the main for the identification of cold resistance of macadamia.(3)Based on the results of cluster analysis and D value of comprehensive cold resistance, eight macadamia varieties were divided into three categories according to the strength of cold resistance. The first group had the strongest cold resistance, including ‘Guireyin No. 4', ‘Guire No. 7', ‘HY', and ‘JW'; the second group had moderate cold resistance, including ‘Guire No. 5' and ‘Guire No. 1'; the third group had the weakest cold resistance, including ‘A16' and ‘Guire No. 6'. Among them, ‘Guireyin No. 4' had the strongest cold resistance; while ‘Guire No. 6' had the weakest cold resistance. The observation results of leaf morphology under low temperature stress were consistent with the clustering analysis results. These results provide a theoretical basis for the study of cold resistance of macadamia, which is of great significance for planting macadamia in the cold area of Guangxi and planting in the North of China.