On the Development of Branch-roots on Successive Nodes of Rice Plants

[摘要] In the present experiment the author wanted to obtain some further understandings on the relations existing between development of the branch-roots and emergence of the leaves, and on the growth mode of the branch-roots under lowland conditions in comparison with that under upland conditions. 1. The author noticed two kinds of branch-roots (bigger and smaller). Diameter of the smaller one was 0.035∼0.075 mm and that of the bigger 0.25∼0.30 mm. The bigger branch-roots branched further but the smaller didn't. 2. Development of the primary, the secondary, the tertiary and the fourthly branch-roots etc. on successive nodes proceeded at the same pace as the period of leaf emergence in the similar way as has been seen in wheat plants. 3. The roots under upland conditions made many branches waving conspicuously, and the number of big secondary roots (mentioned at 1) was twice to three times that under lowland conditions. And branching was repeated so much as to make even fourth order branch-roots under upland conditions, while it did not go further than to have tertiary branch-roots under lowland conditions. Mat roots developed vigorously at the nodes higher than the 8th node under lowland conditions, but they were not observed under upland conditions. Under lowland conditions the root maintain its activity for a shorter period becoming to decrepitude earlier than upland conditions.

[学科分类] 农业科学（综合）