花生品种幼苗耐低温鉴定的生理生化指标筛选

Physiological and biochemical indexes in different peanut seedlings with low-temperature tolerance

为鉴定筛选耐低温花生品种,建立花生耐低温评价方法,构建花生耐低温综合数学评价模型,以11个花生品种为材料,5℃低温胁迫72 h,通过测定胁迫前后花生幼苗叶绿素(SPAD)、叶绿素荧光参数、光合参数、相对电导率、超氧化物歧化酶活性、过氧化物酶活性、过氧化氢酶活性、丙二醛含量以及可溶性蛋白含量等15个生理生化指标,利用各单项指标的耐低温系数作为评价依据,运用主成分分析法、隶属函数分析法以及聚类分析法进行花生耐低温综合评价,并利用逐步回归法筛选与花生耐低温关系密切的生理指标。本实验利用主成分分析法有5个主成分入选,可将15个单项生理生化指标转换为5个互相独立的综合指标,通过隶属函数法和聚类分析法将11个花生品种划分为:耐低温型(山花8号、吉花1954Z和吉花1955Z)、中间型(吉花1953Z、狮头企、冀油6、粤油92和中花8)及敏感型(伏花生、开农53和吉花11)3类;利用逐步回归方程建立花生幼苗耐低温评价数学模型,精度大于99.00%,筛选出净光合速率、实际光化学效率、最大光化学效率、光化学淬灭系数、可溶性蛋白、过氧化物酶和过氧化氢酶7个耐低温鉴定指标。耐低温的花生品种(系)低温胁迫后,反应中心的开放程度较大,光系统受到的伤害较低,能维持较高的净光合速率,能更好地清除花生体内细胞的活性氧和自由基类物质,膜脂质过氧化损伤较低。在相同低温处理时可以通过测定7个指标对花生品种耐低温能力进行快速鉴定和预测,为东北花生耐低温品种选育及大规模品种耐低温评价奠定基础。

To screening and identify peanut tolerance to low temperature, and to establish a comprehensive mathematical evaluation model of peanut, low temperature stress on 11 peanut cultivars were carried out at 5℃ for 72 hours. 15 physiological and biochemical indexes were tested, including chlorophyll SPAD value, chlorophyll fluorescence parameters, photosynthetic gas exchange parameters, relative conductivity, SOD activity, POD activity,CAT activity, MDA content and soluble protein content in peanut seedlings at 0 h and 72 h. The chilling tolerant coefficient of each index was used as basis for evaluation. Comprehensive mathematical evaluation model was evaluated by principal components analysis, hierarchical cluster analysis and regression analysis. Results showed that the15 single indexes could be classified into 5 independent comprehensive components. Cluster analysis results showed that 11 cultivars were divide into 3 tolerant types(Shanhua 8, Jihua 1954Z, Jihua 1955Z), intermediate type(Jihua 1953 Z, Shitouqi, Jiyou 6, Yueyou 92, Zhonghua 8) and sensitive type(Fuhuasheng, Kainong 53, Jihua 11).The mathematical evaluation model for low temperature tolerance was established by stepwise regression equation,and evaluation accuracy of the equation was higher than 99.00%. The screened 7 indexes(Pn, ФPSⅡ, Fv/Fm, 1-qP, SP, POD and CAT) were found closely relate to the tolerance. Results indicated that the reaction center was more open and photosystem was more injured after low-temperature stress in tolerant type that could maintain higher net photosynthetic rate, better removal of reactive oxygen species and free radicals from cells, with low peroxide damage on membrane lipids. The rapid identification and prediction of low-temperature tolerance of peanut cultivar could be carried out by measuring 7 indicators at the same low-temperature treatment. The tolerance cultivars were expected to provide a basis for peanut breeding tolerant to low temperature in Northeast China.