수도의 동일요소에 형성된 각 관근의 신장량은 다음과 같은 관계에 있음을 알았다. 1. 분벽아를 제거하여 각 관근만을 sink로 하였을 경우에는 중륵의 가까운 곳에 형성된 관근이 분벽아쪽에 형성된 관근보다 신장량이 좋았다. 2. 분벽아가 관근과 같이 sink로서 존재할 경우, 전출엽요소에서 출근한 관근이 가장 길었으며 또 분벽경 부근에 형성된 관근이 그 다음이었고 중륵 쪽에 형성된 관근이 가장 짧았다.

1t is well known that the stem is filed with shoot units in the rice plant and each internode bears several crown roots. But it has not yet been ascertained that what controls the differential elongation of the crown roots in the same internode. Thereupon, author had been carried out this experiment to ascertain what controls the elongation of the crown roots in the same internode, especially on the conception of sink-source by leaf-cutting method. Generally, one shoot unit has two important sinks: one axillary bud (tiller) and several crown roots. When we removed the axillary bud, namely shoot unit has one sink: several crown roots, the crown roots formed near the midvein (source) were longer than the crown roots born near the axillary bud. And when the shoot unit has two sinks: one axillary bud and several crown roots, the other way, the crown roots formed at the prophyll unit of the tiller were longest, and the crown roots formed near the midvein were shortest and the crown roots born the near the tiller showed interim length. Juding from the present results, we can suppose that, when shoot unit has two sinks, axillary bud is superior sink than the crown roots. So that axillary bud grows faster than crown roots and tiller becomes a new source. Therefore the crown roots which formed at the new source and the crown roots born the near the new source are longer than others.

• 鄭元一(단국대학교 생물학과) | 정원일