铝毒对覆铁膜水稻生长和根尖细胞壁组分的影响

Effects of Aluminum Toxicity on Growth and Root Cell Wall Composition of Rice with Iron Plaque on the Root Surface

以水稻浙辐802为材料,通过缺磷(-P)和供Fe^(2+)(+Fe)两种方式诱导形成根表铁膜,研究根系生长、根尖铝(Al)含量和根尖细胞壁组分差异。结果表明,100μmol/L Al^(3+)处理48 h,-P和+Fe处理的根相对伸长率降低了66.67%和51.25%,其中-P处理的根相对伸长率显著低于+Fe处理。根尖Al和MDA含量分别比对照组(CK)增加了1 105.6%和322.5%,82.45%和51.61%,-P处理的水稻根尖Al和MDA含量显著高于+Fe处理。Al处理也显著增加根尖细胞壁的果胶、半纤维素1和半纤维素2含量,其中-P处理的增加幅度高于+Fe处理。表明-P处理受Al毒害更加严重。由于-P处理诱导形成的铁膜中的Fe含量显著高于+Fe处理,而铁膜中的P含量则是前者显著低于后者,因此可以认为,根表铁膜上吸附的P在水稻耐铝中起主要作用。

In this study,iron plaque on the root surface was induced by phosphorus deficiency（-P）and Fe2 ＋supply（＋ Fe）. Rice,Zhefu 802,was used to investigate the effect of aluminum（Al） toxicity on root growth,Al content in root tips and root cell wall composition. Relative root length in the-P and＋ Fe treatment was decreased by 66. 6% and 51. 25% when treated with 100 μmol/L Al3 ＋,and it was significantly lower in-P treatment than in ＋ Fe treatment. Al content and malonaldehyde（MDA）content in root tips was increased by 1 105. 6% and 322. 5%,82. 45% and 51. 61% in-P and Fe treatment than CK. Furthermore, Al supply significantly increased pectin, hemicellulose 1 and hemicellulose 2 content,and the increase degree in roots treated with-P is higher than that ＋ Fe pretreatment,indicating rice with-P induced iron plaque was more sensitive to Al toxicity. Although iron content was higher in the iron plaque treated by-P than by ＋ Fe,the phosphorus content adsorbed on iron plaque on the root surface was significantly lower in the former than the latter. These results suggested that phosphorus adsorbed on iron plaque played a major role in Al tolerance.