抄録
Investigation has been carried out on the effect of provisional transplanting of rape seedlings in the nursery bed since 1949. Their results may be summerized as follows. (1) The growth of the provisionally transplanted seedlings in the nursery bed was discouraging and that of its seedlings also was small in size. Accordingly the fresh weight of the aerial part of the seedlings was low. The growth of the aerial portion of the plants after transplanting in the main field was also not satisfactory. Flower bud differentiation and both flowering and maturing were delayed and the yield was also relatively low. (2) Most of the roots had been damaged by provisional transplanting in the nursery bed. Though the rest roots grew up rapidly and vigorously, the growth of the tap-root stopped and it remained short. So that the roots then developed shallow root system which had fine roots around the short tap-root. The stele of root was remarkably lignified, and fine roots were apt to get damaged when seedlings were pulled up from the nursery bed. The increase of roots weve lower in comparison to control seedlings, because of the poor development of new roots. (3) The provisionally transplanted seedlings could take roots quickly after setting in the main field. But the absolute number of leaves were fewer, as a result of which sound leaves were less in number. (4) At any kinds of spacing in the nursery bed, the provisionally transplanted seedlings could not become large, but the growth of the seedlings was uniform. On the contrary, the controlled seedlings were able to get large, but their growth was not uniform. (5) Close correlation could be found between the fresh weight of seedlings and the yield, but on the other hand there was less correlation between the ratio of pith length to the width and the yield.
