隔月発芽試験による雑草生育期の季節的消長

抄録

1. Twelve kinds of annual weeds were selected to clarify the autecological characters of weeds in the fields cultivated in 1956. These weeds were planted on porcelaine germinating dishes every other month since May, and the differences of the following six stages were observed : budding stage, seedling stage, vegetating stage, flowering stage, fruiting stage and withering stage. 2. The results of these germinating tests are as follows : 1) The weeds which germinated in the early season, were remarkable in the growth of their leaves and stalks in the growth stage, and those which germinated a month later than the former were distinguishably slow in their growth, their branching and tillering declined and they became gradually dwarfed. 2) The earlier the seeds germinated, the longer their flowering period became. 3) The later the seeds germinated, the lewer the seeds were produced, depending upon the growth, branching and tillering. 3. Most of the seedlings which sprouted after August flowered, but their seeds did not ripen fully. Seedlings which sprouted after September stopped growing and most of them died in the middle of October owing to the frost. 4. From the results of the observations mentioned above, the writer is of opinion that the amount of seeds of the annual weeds sprouting after August is extremely small in Hokkaido, and the cultivating fields are not greatly influenced by the weeds sprouting after August.