荳科飼料作物の不稔種子発生機構の形態学的並びに生理学的研究 : 第5報 キドニーベツチに於ける1粒莢の生成に就いて

抄録

The pod of kidney vetch (Anthyllis vulneraria L.), when matured, contains usually only one seed. But the ovary at its young stage involves several ovules, ranging 2-4. In this experiment, some embryological observations were carried out, using two-ovuled ovaries, to know the causes concerned about formation of one-seeded pod. The results obtained are summarised as follows : 1) When classified by the ovule number in ovary, 81.5% of 363 ovaries examined were two-ovuled ovaries as shown in Fig. 1. 2) When the ovaries are classified by numbers of fertilized ovules involved, 17.4% of them contained only one fertilized ovule as shown in Fig. 2. Out of them, 8.7% contained one normal but non-fertilized ovule, the remained 8.7% contained one abnormal ovule in which the embryosac was not normally formed. Those ovaries should grow into one-seeded pods. 3) Meanwhile, 77.3% were the ovaries containing two fertilized ovules. In this case, however, the two fertilized ovules never develop evenly, but one of them was arrested in its growth and degenerated without exception. The degeneration of fertilized ovule began from about 4th day after pollination, and one-seeded pods were confirmed on about 7 th day. 4) As to the position of normal seeds in the pods, so far as this experiment is concerned, the seed-setting was found more highly at the apical (stylar) position of the ovary than at the basal as shown in Fig. 3. 5) As to the one-seeded pod formation in 3- and 4- ovuled ovaries, the main cause was the degeneration of fertilized ovules as in the case of two-ovuled ovaries.