Relationships between Root Hair Elongation, and the Movement of Nuclei and Cytoplasmic Granules in Root Hairs of Rice Plants

[摘要] This experiment was carried on to find whether some relationship between rot hair formation and their elongation, and movement of nuclei and cytoplasmic granules in them exists or not. The living and killed root hairs were observed with the ordinary and phasic microscope. The following results were obtained. While root hairs initiated at about 1/3 of the way back from the apical ends of the short cells in epidermis, most of nuclei were located at the centre of short cells. After root hairs elongated to about 20∼30 μ, nuclei in short cells moved to the bases of root hairs and then migrated inside them. While root hairs were elongating, the nuclei inside them did not lie in a constant distance from the tip. For example, in the rot hairs measuring 150μ, the nearest and farthest points from the tip where the nuclei were found were 50μ and 125μ respectively. Furthermore, it was found that in the still elongating or already matured root hairs the nuclei continuously moved to-and-fro inside them and sometimes entered back to the hair-bearing cells. Two types of cytoplasmic granules were found in root hairs; one was 2∼4μ in diameter and the other 0.5∼1.0μ. The larger granules moved irregularly and independently of protoplasmic streaming, and strictly speaking, the movement of the small granules also did not keep pace with the protoplasmic streaming, that is, they sometimes stopped moving, and sometimes moved a short distance in the opposite direction against the streaming and followed it again. No difference was observed between the speeds of the protoplasmic streaming of the elongating and matured rot hairs. From these results it is concluded that there is no relationship between root hair formation and their elongation, and the movement of nuclei and cytoplasmic granules in root hairs.

[学科分类] 农业科学（综合）