Root growth is reduced in soils with low pH [H⁺] and abundant soluble aluminum [Al³⁺], which can be a consequence of the interaction between Al³⁺ and cell wall composition. The competition between Al³⁺ and Ca²⁺ toward binding to pectin molecules was evaluated in roots of Urochloa decumbens, an African grass highly adapted to acidic Al-rich soils. Variations in the composition and distribution of pectins can change the extensibility, rigidity, porosity, and adhesive properties of plant cell walls, which were tested in seedlings of U. decumbens exposed to pH 3.5, 4.5 and 5.8 and to 0, 80, 160 and 320 μM of Al³⁺ for 80h. Root growth corroborated that U. decumbens is very tolerant to soil acidity, with effective reduction of root growth only at pH 3.5. Immunocytochemical approaches demonstrated variations in pectin composition induced both by Al³⁺ and by H⁺ in root tissues and zones. Based on the usual linkage between Ca²⁺ and pectins, Density Functional Theory (DFT) analyses indicated that Al³⁺ bound easier to pectins than Ca²⁺ did, leading to the formation of more Al³⁺-pectate complexes than Ca²⁺-pectate complexes, which resulted in higher rigidity of cell walls, and hampered cell extension.

pH值[H ⁺ ]低且可溶性铝[Al ³⁺ ]丰富的土壤中根系生长减少，这可能是Al ³⁺与细胞壁成分相互作用的结果。在Urochloa decumbens（一种高度适应酸性富含Al的土壤的非洲草）的根中评估了Al ³⁺和Ca ²⁺之间与果胶分子结合的竞争。果胶组成和分布的变化会改变植物细胞壁的延展性，刚度，孔隙率和粘附性，这在暴露于pH 3.5、4.5和5.8以及暴露于0、80、160和0.1的U. decumbens的幼苗中进行了测试。320μM的Al ³⁺持续80h。根的生长证实了U. decumbens非常耐土壤酸度，仅在pH 3.5时有效减少了根的生长。免疫细胞化学方法表明，在根部组织和区域中，Al ³⁺和H ⁺均可诱导果胶组成的变化。基于CA之间的通常的联动²⁺和果胶，密度泛函理论（DFT）分析表明，铝³⁺到果胶除Ca结合更容易²⁺那样，导致更多的Al的形成³⁺ -pectate络合物除Ca ²⁺ -果胶复合物，导致细胞壁更高的刚性，并阻碍了细胞的延伸。