Some Observations on the Root Development in Rice Plant with Respect to Its Concurrency with Leaf Emergence and Internode Elongation

[摘要] Growth of the above-and under-ground parts of rice plant was observed to clarify their developmental phase coincidence. 1. The concurrence among the leaf emergence, the internode elongation, and the ascent of node-locus where the emergence of new roots were prevailing in the main stem is presumed as follows: At the time of emergence of the N-th leaf (denote the node number from which the N-th leaf emerged as n), the (n-2)∼(n-3)-th internodes attained their full lengths, and crown root emergence was prevailing on the (n-3)-th node. 2. But, at the conversion stage of leaf emergence, the ascending pace of root emarging locus and the rate of root number increase were checked, and at the stage of uppermost leaf emergence, crown root development was observed on the (n-4)-th node. 3. The total area of the cross section of secondary xylems per single root measured larger as the root emerging node-locus ascended higher, up to the conversion stage of leaf emergence, and it diminished, thereafter. 4. The secondary thickening of the metaxylem was not observed in the root of any locus.

[学科分类] 农业科学（综合）