双子葉類側生前葉の着生方向に関する研究

第1報 概論

抄録

In this paper, purposes, methods and materials were described and a part of the results obtained in some species of annual and biennial dicotyledonous plants was preliminarily reported. Special studies in detail will appear in the future papers of this series.
The primary and secondary branches were observed in genetic sequence from the lowest one towards the upper along the respective mother axis. After the observation on hundreds of branches, the cathodic prophylls on the branches of the same genetic number were added together. The results thus obtained in each species were expressed by the frequency curve of cathodic prophylls of its own.
In the case of the primary branch, the frequency curves may be divided by their trend into three types, i.e. type A (Xanthium canadense Mill., Fig. 4, A), type B (Erigeron sumatrensis Retz., Fig. 4, B; Nigella damascena L., Brassica Napus L., Brassica Rapa L. var. laciniifolia Kitam.) and type C (Impatiens Balsamina L. Fig. 4, C1, C2; Kochia Scoparia Schrad., Fig. 4, C3; Amaranthus ascenders Loisel.). In the case of the well-developed secondary branch, the frequency curve of cathodic prophylls is fundamentally similar in each species to that of the primary branch, but it is somewhat simpler.
In every species the cathodic prophylls on the branches situated at the basal and terminal parts of a main axis and of a primary branch axis show characteristic local variations of frequency, different from the general trend of the frequency curve. It was preliminarily interpreted that these basal and terminal variations have resulted from some factors such
as the special phyllotaxis, the plastochrone change, etc., characteristic to the basal and terminal parts of an axis. Analytical studies on the basal and terminal effects will give some suggestions upon the mechanism which determines the anodic or cathodic positions of prophylls.