石灰性土壤上植物根际中Fe,Mn的形态分布及其与植物吸收的关系

研究了石灰性土壤上５种作物品种根际微生态环境中Ｆｅ、Ｍｎ的形态分布．结果表明，交换态Ｆｅ（ＥＸ－Ｆｅ）、碳酸盐结合态Ｆｅ（ＣＡＲＢ－Ｆｅ）、无定形氧化铁（ＡＯ－Ｆｅ）和交换态Ｍｎ（Ｅ－Ｍｎ）、碳酸盐结合态Ｍｎ（ＣＡＲＢ－Ｍｎ）在根际土壤中都呈现明显的累积．各品种根际中的累积量有较大差异．相关分析表明，黄潮土上植株含Ｆｅ量、吸Ｆｅ量与根际土壤ＡＯ－Ｆｅ含量呈显著正相关．根际有效态Ｆｅ累积不仅是根际ｐＨ作用的结果，与根系分泌物对难溶性Ｆｅ活化有关．根际有效态Ｍｎ累积则受到根际土壤Ｅｈ的影响．

Distribution and forms of iron and manganese in calcareous rhizosphere soils as related to plant uptake

In this paper,the distribution and forms of Fe and Mn in rhizosphere soils planted with five varieties of crops were investigated by using the rhizobag system.The results show that exchangeable Fe(EX-Fe),carbonate-bound-Fe(CARB-Fe),amorphous Fe oxides(AO-Fe)and exchangeable Mn(EX-Mn),carbonate-bound-Mn(CARB-Mn)are accumulated significantly in rhizosphere soils.The amount of which are different among the rkizosphere soils of five crops.Correlation analysis shows that both the Fe content in the plants and the amount of Fe absorbed by plants are positively correlated with AO-Fe content in rhizosphere of yellow fluvo-aquic soil.Besides the influence of PH change in rhizosphere, the mobilization of insoluble Fe-by root exudates may be related to the accumulation of available Fe in rhizosphere.The accumulation of available Mn in rhizosphere is associated with rhizosphere Eh.