甘蓝型油菜幼苗期耐镉性评价方法的研究

Development of evaluation method for cadmium tolerance in Brassica napus seedlings

为选择一种科学有效的甘蓝型油菜幼苗期耐镉性评价方法,用0、1、2.5、5、10、20、30mg/L的镉液处理13个品种的幼苗1周,观察形态学变化,统计其生长指标,并利用多种方法进行耐镉性评价。结果表明:(1)镉胁迫后甘蓝型油菜幼苗表现出植株矮小、主根和侧根变短、侧根数减少、叶片面积减小、叶片发黄等症状;(2)选择5mg/L和相对根长、相对茎叶长、相对植株总长、相对根鲜重、相对茎叶鲜重、相对植株总鲜重、相对根干重、相对茎叶干重和相对植株总干重共9个指标,分别作为甘蓝型油菜幼苗期耐镉性评价的处理浓度和评价指标;(3)依据单个指标进行耐镉性评价的结果比较片面,多指标评价综合了幼苗镉胁迫后多方面的表型变化,评价结果更加科学。多指标评价方法中的主成分分析法选择累积方差贡献率为0.92的三个主成分对甘蓝型油菜进行耐镉性评价,能够客观地将参试的材料分成耐镉性和镉敏感两组,较综合得分法和隶属函数值法为最优方法。

To efficiently evaluate cadmium（ Cd） tolerance of Brassica napus seedlings,13 germplasm accessions were studied on morphological responses to 6 different Cd stress concentrations（ 0,1,2. 5,5,10,20,30 mg / L Cd solution）. Results showed that after Cd stress,rapeseed seedlings turned dwarf,taproot and lateral root became shorter with less lateral roots,had smaller leaf area and more yellow leaves. 5mg / L Cd solution was selected as an optional concentration. 9 phenotypic traits（ including relative root length,relative shoots length,relative plant length,relative root fresh weight,relative shoots fresh weight,relative plant fresh weight,relative root dry weight,relative stems dry weight,and relative plant dry weight） were selected as Cd tolerance evaluation indexes.Multiple indicators method was more effective than single index method on evaluation,because it integrated all phenotypic traits responding to Cd stress. Among this methods,principal component analysis method was the best method compared to Subordinate function value method and integrated score method. By 3 principal components（ with APC 0. 92）,materials were classified into Cd tolerance group and Cd sensitive group.