This paper reviews the formation and feature of iron and manganese plaque , alleviation of metal ( loid ) toxicity via adsorption and accumulation , eutrophication purification , plant acid proof and barren resistance 文章综述了植物根表铁锰氧化物的形成与特征，对有害金属和类金属污染物、有机污染物的吸附和富集作用，对富营养化水体的净化作用，以及提高植物的耐酸和耐贫瘠能力。
2.
Y chromosome is transmitted in the form of hap - loid , leading to extreme disequilibrium of y chromosome genetic markers distribution in different population . the prerequisite of str application in forensic medicine is establishment of a database of population y - str loci haplotype distribution . therefore we need to form haplotypes by using the known highly polymorphic str loci and detect more local population 由于y染色体呈单倍体遗传，导致y染色体遗传标记在不同人群中的分布极不平衡，群体差异比常染色体str位点更加显著，在法医学应用的前提条件是：建立含有多个y - str位点的单倍型的群体分布数据库。
