著者

伊藤 健次 井手 欽也 井之上 準

出版者

日本雑草学会

雑誌

雑草研究 (ISSN:0372798X)

巻号頁・発行日

vol.6, pp.100-107, 1967-12-25

被引用文献数

5

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1) In southern part of Japan, the time of flowering of Artemisia princeps Pamp. is late september to early october. As the results of experiments the flowering was observed under short day (8 hours light), and did not under long day condition (continuous light). 2) Number of head per plant was 2,000〜14,000, and a head consisted of about 15〜17 florets. On the other hand, the rate of fructification of the florets was about 2〜40 per cent, averaged about 20 per cent. From the results, number of seeds per plant was about 5,000〜40,000. 3) About 20 days after flowering, the seeds had an ability of germination, and it reached maximum after about 50 days. This result showed that the seeds had no dormancy. From our observations, it seemed that the seeds germinate from late autumn to early winter and pass through winter season with cotyledonary plants. 4) Effect of temperature on germination of the seeds was as follows: minimum temperature O〜5℃, optimum temperature ; 20〜30℃, maximum temperature ; 35〜40℃. 5) The rate of emergence of cotyledonary plants war good under the soil of 10〜20 per cent soil moisture content, and it decreased with the increase of soil moisture content. However, the seeds were able to germinate in boiled water, and it grown up to 6 leaf stage under the water. 6) The rate of emergence was also affected by the depth of seeding, and it decreased with the increase of the depth of seeding. As the effect of soil compaction of cover soil after seeding, in the plot of 0.1kg/cm^3-compaction 30 per cent of seeds emerged at O. 5 cm-seeding depth and did not emerge at 1.0cm-seeding depth. In the plot of 0.2kg/cm^3-compaction no emergence occured even at the plot of 0.5cm-seeding depth.