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以重庆酸雨区马尾松林地土壤为例,通过马尾松幼苗盆栽试验法研究了酸性土壤–马尾松根系界面铝(Al)的化学行为.林地土壤中的铝可分级为交换态铝(Alex)、有机态铝(Alor)、氧化态铝(Alox)、碳酸盐态铝(Alc)和不溶态铝(Alin).研究结果表明:共存盐基离子Ca~(2+)、Mg~(2+)、K~+和Na~+对Al~(3+)在土壤–马尾松根系界面行为的影响呈正效应(缓解铝毒),影响顺序为Ca~(2+)>Mg~(2+)>K~+≈Na~+.全氮和全磷含量与根系铝含量呈正相关;土壤有机质(Organicmatter,OM)含量与根际Alor浓度呈正相关.土壤pH值(<5.0)与根际Alex呈负相关,根际Alex大于非根际Alex,马尾松根系铝的吸收主要取决于根际土壤Alex含量,Alex进入根系后逐步与根细胞壁小分子有机化合物配位,主要以Alor累积于根部.图1表5参20
Taking Masson pine forest soil in Chongqing acid rain area as an example, the chemical behavior of aluminum (Al) in acid soil-masson pine root system was studied by means of pot test of Pinus massoniana seedling.Aluminum in forest soil could be graded as exchangeable aluminum (Alex) Alor, Alox, Al and Alin. The results show that coexisting base ions Ca ~ (2 +), Mg ~ (2+ ), K ~ + and Na ~ + had positive effect on Al ~ (3 +) in the soil-masson pine root interface. The order of effect was Ca ~ (2 +)> Mg ~ (2+) > K ~ + ≈ Na ~ +. The contents of total nitrogen and total phosphorus were positively correlated with the content of aluminum in root system. The content of organic Matter (OM) was positively correlated with the Alor concentration in rhizosphere soil. Negatively correlated, the rhizosphere Alex greater than non-rhizosphere Alex, Pinus massoniana root aluminum absorption mainly depends on the rhizosphere soil Alex content, Alex into the root and gradually with the root cell wall small organic compounds, mainly in Alor accumulation in the root. 1 Table 5 Reference 20