油菜根尖细胞壁果胶含量及其甲基酯化程度与耐铝性的关系

以耐铝性差异显著的2个油菜基因型湘油杂3号(耐性)和赣油杂2号(敏感)为材料,研究了铝胁迫条件下根系生长情况,根尖铝含量,根尖细胞壁果胶含量及其甲基酯化程度与耐铝性的关系。结果表明,湘油杂3号的耐铝性显著高于赣油杂2号;0~5 mm根段积累的铝显著高于5~10 mm根段;距油菜根尖0~5 mm根段,敏感基因型果胶含量高于耐性基因型,且前者根尖及细胞壁对铝的积累量也显著高于后者;采用1.0 mol/L NH3.H2O预处理根尖2 h降低细胞壁果胶甲基酯化程度后,耐性和敏感基因型根尖细胞壁对铝的积累量分别下降了14.5%和19.1%。这些结果表明,细胞壁果胶含量及其甲基酯化程度可能是导致不同油菜基因型根尖及细胞壁铝含量、耐铝性差异的重要原因。

Cell Wall Pectin Content and Methylation Degree in Relation to A1 Resistance in Brassica campestris L.

In this paper,two genotypes of Brassica campestris L.,Alresistant Xiangyou No.3 and Al-sensitive Ganyou No.2,were used to investigate the effects of Al stress on the root growth,root tip Al content,cell wall pectin content and the methylation degree that were related to Al resistance.The result showed that the root elongation was decreased with the increase of Al concentrations applied,but the inhibition was more conspicuous for Ganyou No.2,indicating the higher Al resistance for Xiangyou No.3.In both genotypes,the Al content in 0-5mm root segments was significantly higher than that in 5-10mm.In 0-5mm root segments,the cell wall pectin content of Ganyou No.2 was significantly higher than that of Xiangyou No.3.The Al contents accumu-lated by root tip and cell wall in Ganyou No.2 were significantly higher than that in Xiangyou No.3.Reducing the methylation degree of pectin in cell walls with 1.0mol/L NH3·H2O for 2h,the accumulated amount of Al in cell wall was decreased by 14.5% in Xiangyou No.3 and 19.1% in Ganyou No.2.These results indicated that cell wall pectin content and the degree of methylation contributed to genotypic differences in Al accumulated content in root tip and cell wall,thus in Al resistance in Brassica campestris L.