根系生长空间对玉米生长和养分吸收的影响

Effects of root growth space on growth and N and P uptake in corn(Zea mays L.)

【目的】研究根系生长空间对玉米植株生长、养分吸收及产量的影响。【方法】采用根箱限根的方法,使玉米根系生长空间分别为25,50,75和100 L/株。分别在玉米大喇叭口期和吐丝期取样,测定其生长和养分吸收状况,在生理成熟时测定产量及其构成因素。【结果】与无限制根系生长空间（100 L/株）处理相比,限制根区体积在生殖生长阶段（大喇叭口期-吐丝期）使玉米地上部和根系干质量显著降低（P〈0.05）,在营养生长阶段（出苗-大喇叭口期）使玉米地上部干质量显著降低（P〈0.05）;在营养生长和生殖生长阶段,使玉米植株氮浓度、含氮量和含磷量及氮养分比吸收率显著下降（P〈0.05）,但对磷养分比吸收率没有显著影响;玉米籽粒产量随根区体积的增加而提高。【结论】限制根区体积可抑制玉米根系下扎,导致过多根系充满0~20 cm表层土壤孔隙,使玉米根系生长受抑制,N吸收效率下降。

【Objective】The influence of confinement of root growing space of corn（Zea mays L.） upon plant growth,N and P uptake and crop yield in corn was discussed.【Method】Soil culture was carried out with the corn planted in different volume containers（25,50,75 and 100 L/plant） to confine the space of root growth by using root boxes.Samples were taken at male tetrad and at silking stage.Dry weight,N and P concentrations and contents of shoot and root in corn were measured.Grain yield and its components were measured at the physiological maturity.【Result】From emergence to male tetrade and from male tetrade to silking shoot specific dry weight increment,N and P specific absorption rate were calculated.Restriction of root growth space reduced shoot and root growth（P〈0.05）at silking stage,while it reduced only shoot growth（P〈0.05）at tetrade stage.At both stages,restriction of root growth space decreased N concentration and N and P content,reduced recovery of both nutrients,decreased N specific absorption rate（P〈0.05）,but did not affect P specific absorption rate.Corn grain yield increased with the increase of root growth space.【Conclusion】This showed that the restriction in root zone volume results in a high root density in the surface soil layer,so a high percentage of soil pores fills mass roots and root growth and nutrient uptake efficiency are also reduced.