Rangel Andrés Felipe, Rao Idupulapati Madhusudana, Horst Walter Johannes
Institute of Plant Nutrition, Leibniz University of Hannover, Herrenhaeuser Strasse 2, Hannover, Germany.
Physiol Plant. 2009 Feb;135(2):162-73. doi: 10.1111/j.1399-3054.2008.01183.x. Epub 2008 Dec 5.
The role of the intracellular distribution and binding state of aluminum (Al) in Al toxicity, using Al exchange and Al fractionation methodologies, were studied in two common bean (Phaseolus vulgaris L.) genotypes differing in Al resistance. These two genotypes are characterized by a similar initial period (4 h) of Al sensitivity followed by a contrasting recovery period (8-24 h). A higher initial Al accumulation in Quimbaya (Al resistant) in the 5-mm root apex compared with VAX-1 (Al sensitive) could be related to its higher content of unmethylated pectin and thus higher negative charge of the cell walls (CWs). The binding state and cellular distribution of Al in the root apices revealed that the root elongation rate was significantly negatively correlated with the free apoplastic and the stable-bound, not citrate-exchangeable CW Al representing the most important Al fraction in the root apex (80%), but not with the symplastic and the labile-bound, citrate-exchangeable CW Al. It is postulated that the induced and sustained recovery from the initial Al stress in the Al-resistant genotype Quimbaya requires reducing the stable-bound Al in the apoplast thus allowing cell elongation and division to resume.
利用铝交换和铝分级分离方法，研究了铝（Al）在细胞内的分布和结合状态在两种耐铝性不同的普通菜豆（Phaseolus vulgaris L.）基因型铝毒性中的作用。这两种基因型的特点是，铝敏感性的初始阶段（4小时）相似，随后是对比鲜明的恢复期（8 - 24小时）。与VAX - 1（铝敏感型）相比，Quimbaya（铝抗性型）在5毫米根尖中较高的初始铝积累量可能与其未甲基化果胶含量较高有关，因此细胞壁（CWs）的负电荷也较高。根尖中铝的结合状态和细胞分布表明，根伸长率与自由质外体铝和稳定结合铝显著负相关，而不是与代表根尖中最重要铝组分（80%）的不可柠檬酸交换的细胞壁铝负相关，但与共质体铝和不稳定结合的、可柠檬酸交换的细胞壁铝无负相关。据推测，铝抗性基因型Quimbaya从初始铝胁迫中诱导并持续恢复需要减少质外体中稳定结合的铝，从而使细胞伸长和分裂得以恢复。
