中文摘要：

文章采用卷纸培养和分层琼脂培养的方法，研究磷对大豆主根伸长影响的结果表明：低磷[0．2gmol（KH2PO4）·L^-1]显著促进大豆主根伸长，特别是延长大豆主根根尖至最新侧根问的距离；组织切片表明，低磷对主根伸长的促进主要是通过延迟主根伸长区的分化实现的，并且低磷对主根的促进作用不受亚磷酸盐的影响。琼脂分层培养的结果表明，在磷分布不均匀的条件下，低磷影响主根的伸长生长，上层或下层不施磷的大豆主根伸长均有增加。

英文摘要：

The study elucidated the effect of phosphorus （P） on soybean taproot elongation by the methods of rolled paper culture and stratified agar culture. Our results showed that the taproot elongation of soybean, especially the distance from the taproot tip to newest lateral root, was stimulated by low phosphorus. The taproot elongation promoted by low phosphorus mainly attributed to the delay of the differentiation in the elongation zone of soybean root and could not be affccted by applying phosphite. Under the condition of heterogeneous distribution of phosphorus in stratified agar culture, low phosphorus accelerated taproot elongation with no phosphorus in the top or bottom agar.