土层水分非均匀供应下施锌对玉米植株中Ca、Fe、Mn、Cu吸收积累的影响

进行分层盆栽试验,模拟田间土壤剖面上下层水分不均匀分布条件,研究表层土壤施锌对玉米植株吸收Ca、Fe、Mn和Cu养分的影响。结果表明:上层土壤干旱抑制了苗期玉米植株生长,降低了地上部Ca、Fe、Mn分配比例。上层土壤干旱情况下,增加下层土壤水分供应,并没有提高植株生长和养分元素的吸收量。施锌明显促进了玉米地上部生长,在土壤水分充足时,施锌对植株生长效果更明显。不论土壤水分状况如何,施锌显著降低了植株中Ca、Fe、Mn、Cu浓度,对植株吸收积累Fe有拮抗作用;上层土壤干旱条件下,施锌还降低了地上部和整株中Mn以及根部Cu的积累量。施锌对植株体内Ca、Fe、Mn、Cu向上运输没有显著性影响。研究表明土壤表层干旱条件下,即使增加土壤水分,尚不能提高玉米植株生长和对Ca、Fe、Mn、Cu等养分的吸收利用。施用锌肥可以提高作物对土壤水分利用,但要注意对作物吸收Fe与Mn的拮抗作用,适当配合铁锰等养分供应。

Effects of Zn application on uptake of Ca, Fe, Mn and Cu by maize plants under different water conditions in soil layers

A pot experiment with splitting vertically layer culture systems was conducted to study the effects of Zn application in topsoil on maize plant growth and the uptake of Ca,Fe,Mn and Cu in two soil layers under different water conditions.The results showed that plant growth was inhibited by soil water deficit in topsoils,even when the water supply in subsoils was improved.The translocation of Ca,Fe and Mn to shoots in maize plants was decreased by drought in topsoil.The shoot biomass and Zn accumulation in shoots were significantly enhanced by Zn application.Under adequate moisture supply in whole soil layers,the increases of plant growth and Zn uptake due to Zn application were more remarkable than that under drying conditions.Whatever soil water condition,Zn application decreased Ca,Fe,Mn and Cu concentrations in shoots and plant Fe accumulation.However,Zn application did not affect Ca,Fe,Mn or Cu translocation to shoots.Under drought in upper soil layer,Zn addition also reduced Mn accumulation in shoots and Cu accumulation in roots.Our research suggested that adequate water supply in subsoil couldn′t enhance plant growth or plant Ca,Fe,Mn and Cu uptake if maize plants were grown under drought stress.Zn was recommended to apply if irrigated adequate water in soil layer so as to promote plant water use,but more attention should be paid to the antagonism of Zn on crop Fe and Mn uptake.