On the Elongation of Root Hairs of Rice Plants

[摘要] A few studies on the elongation of root hairs of rice plants in relation to ecological conditions (nitrogen fertilizer, water percolation, etc.) had been carried out by the authors. But the study on the elongation of root hairs in relation to physiological conditions of roots has not been ascertained. The present work was carried out to study the elongation of root hairs in relation to the speed of root growth, root diameter, and thickening of vessel element. The following results were obtained: Generally, at the root apex, papilla bears firstly and then elongation of root hair begins; in this case, at the early stage the growing speed is very slow. Gradually the growing speed of root hairs becomes speedy with time, but at the later stage it decreases and finally stops. As regards the elongation of root hairs in relation to the diameter and the growing speed of the roots, it was found that the thicker roots have longer root apex-papilla distance (i.e. the distance from the root apex excluding root cap to the first papilla), longer root-hair-growing zone and longer root hairs as compared with the thinner roots, and that the roots which grow speedy have longer root hairs than the roots which grow slowly. It was also found that there is close correlation between the elongation of root hairs and the thickening of vessel elements; at the point that papilla were ascertained, matured protoxylem elements (PX) were seen, and at the point that elongation of root hair becomes maximum, matured early metaxylem elements (MXV I) were seen, and at the point that elongation of root hairs stopped, matured late metaxylem elements (MXV II) were observed.

[学科分类] 农业科学（综合）