花生对镉胁迫的生理响应及品种间差异

深入研究花生镉毒害机理对于筛选和利用抗镉污染花生种质资源具有重要的理论和实际意义.本文以14个花生品种为材料，以花期花生功能叶叶绿素含量、根系和叶片丙二醛含量、细胞膜透性和根系氧化活力等生理参数为指标，利用人工气候箱砂培试验，研究了6种Cd浓度胁迫下花生植株的生理毒害反应及其品种间遗传差异.结果表明: 在0～60 mg Cd ·L^-1范围内，随着营养液添加Cd浓度的增加，花生叶绿素含量和根氧化活力极显著降低，根、叶细胞膜透性和根、叶丙二醛含量极显著增加，且品种与Cd浓度间具有显著交互作用; 花生根、叶细胞膜透性是对镉胁迫响应最为敏感的生理参数，而叶绿素含量对镉胁迫响应相对不敏感; 各生理参数与营养液Cd浓度关系的线性回归方程的斜率(b)与截距(a)之比值的绝对值︱b/a︱能够较好地描述不同花生品种对镉胁迫的敏感性.对6个生理参数的︱b/a︱值进行综合赋值及敏感性五级聚类分析得知，在供试花生品种中，“中花4号”、“湘农55号”和“湘农3010-w”等3个品种对镉反应高度敏感(Ⅰ级);“莱农29”、“湘农小果w2-7”、“丰花2号”、“莱农13”、“豫花15号”和“丰花3号”等6个品种反应敏感(Ⅱ级);“湘农312”、“祁阳小籽”和“平度01”等3个品种反应一般(Ⅲ级);“花育23 ”和“花育20”等两个品种反应钝感(Ⅳ级).

Physiological responses of different peanut (Arachis hypogaea L.) varieties to cadmium stress.

To have a deep understanding on the mechanisms of cadmium (Cd) toxicit y on peanut plants is of theoretical and practical significances for the selecti on and utilization of Cd-resistant peanut germ plasm resources. With fourteen peanut varieties as test materials and taking the chlorophyll content of functio nal leaves, malondialdehyde (MDA) content and cell membrane permeability of root s and leaves, and oxidative vitality of roots at flowering stage as test physiol ogical parameters, a sand culture experiment was conducted in an artificial clim a te chamber to investigate the physiological responses of different peanut variet ies to six levels of Cd stress. The results showed that within the range of 0〖 KG-*2〗-〖KG-*7〗60 mg Cd·L-1 addition, the chlorophyll content of functional leaves and the oxida tive vitality of roots decreased significantly with increasing Cd addition, whil e the MDA content and cell membrane permeability of leaves and roots were in adv erse. The cell membrane permeability of roots and leaves was the most sensitive physiological parameter, while the chlorophyll content of functional leaves was the least sensitive one in the responses of peanut plant to Cd stress. In the li near regression equations describing the relationships between test physiologica l parameters and Cd concentrations in nutrient solution, the absolute value of s lope (b)/intercept (a) ratio, ︱b/a︱, could better describe the sen sitivity of peanut plants to Cd stress. It was known from the integrative evaluation of︱b/a︱values and the cluster analysis of sensitivity that among the fourteen peanut varieties, “Zhonghua-4”, “Xiangnong-55” and “Xiangnong-3010-w” were hi ghly sensitive to Cd stress (first grade), “Lainong-29”, “Xiangnongxiaoguo-w2-7”, “Fenghua-2”, “Lainong-13”, “Yuhua-15” and “Fenghua-3” were sensitive (second grade), “Xiangnong-312”, “Qiyangxiaozi” and “Pingdu-01” were less sensitive (third g rade), while “Huayu-20” and “Huayu-23” were insensitive (forth grade).