湿地挺水植物根系土壤中的磷形态变化与分析

The morphological changes and analysis of phosphorus in the root soil of emergent aquatic plant in the wetland

以野鸭湖湿地中扁秆藨草、芦苇和茭白3种优势挺水植物为研究对象,利用化学连续提取法对根际和非根际土壤中不同形态无机磷和有机磷进行分级提取,分析了不同形态磷的含量特点和分布规律,探讨了植物对磷素的潜在吸收机制.结果表明,根际Ca-P含量均显著低于非根际,Ex-P、Fe-P和Oc-P相反.4种形态有机磷含量均为根际高于非根际,表现出累积的趋势.根际Ca-P/TP值显著小于非根际,说明植物将有效性低的Ca-P形态大量转化为其他形态无机磷以供自身利用;根际HR-OP/TP值小于非根际,而MR-OP/TP大于非根际,表明稳定有机磷形态有向活性高的有机磷转化的趋势;TIP/TP均为根际小于非根际,而TOP/TP根际大于非根际,推测根系在吸收利用磷素的过程中主要吸收无机磷,同时积聚大量有机磷供转化后利用.

Take Scirpus planiculmis、Phragmites communis and Zizania aquatica in Yeyahu Wetland as studied objects, then different forms of inorganic phosphorus （IP） and organic phosphorus （OP） in rhizosphere and non-rhizosphere soil samples were extracted by chemical continuous extraction. The content characteristics and distribution regularities of different P forms were analyzed, and the P absorption mechanism of plants was also discussed.Results show that the content of Ca-P in the rhizosphere is significantly lower than non-rhizosphere,while Ex-P、Fe-P and Oc-P are the opposite.Also there is a OP cumulative trend as all the four different forms of OP in rhizosphere are higher than non-rhizosphere. The Ca-P/TP in rhizosphere is significantly less than that of non-rhizosphere, which indicated that the plants can transform Ca-P which is difficult to be absorbed into other forms to use.HR-OP/TP in rhizosphere is less than non-rhizosphere, but MR-OP/TP is just the opposite, indicating that there is a trend that the stable forms of OP can convert into high activity ones. TIP/TP in rhizosphere of all the three plants is less than the non-rhizosphere, meanwhile, almost the whole TOP/TP in rhizosphere is greater than non-rhizosphere. Accordingly, a hypothesis can be infered that in the P up-take process of roots, IP is the main part which is absorbed, yet a large number of OP wil be accumulated until transformed.