マメ料作物の根群形成に関する研究 : 第7報 冬作物の胚軸における不定根の生育について

抄録

1. The object of the experiment was to study the growth of adventitious roots from the epicotyl or hypocotyl of winter legumes. Eight species (broad bean, pea, lupin, red clover, subclover, Egyptian clover, common vetch and Chinese milk vetch) were examined under the three methods of cultivation i. e. a standard cultivation, mulchirlg, and deep sowing (6cm below soil surface). 2. In broad bean, the roots developed adventitiously from the epicotyl even under the standard method of cultivation (Table 1 and Fig. 1), although fresh weight of the adventitious roots was only 5 % of the total root weght. Under both mulching and deep sowing, development of adventitious roots was marked (Fig. 2 A-E), particularly, in the plot mulched at the time when fourth leaf on the main stem spread out (Fig. 2-A). 3. Adventitious roots did not developed on neithdr pea nor common vetch except the deep sowing treatment (Fig. 3). 4. A large number of adventitious roots developed from the hypocotyl of lupin after flowering (Fig. 4-C), it would be caused by heavy rain. Clovers and Chinese milk vetch have a large and deep tap root compared with other species but very few adventitious roots developed (Fig. 4-D). 5. Among factors which influence the adventitious roots were considered to be: secondary thickening growth of the epicotyl or hypocotyl (Table 3 and Fig. 3) and the type of root system. The close relation between the growth of adventitious roots and that of secondary thickening of the epicotyl or hypocotyl was recognized. In broad bean with vigorous growth of the secondary thickening, the adventitious roots greatly developed and in pea or common vetch belonging to the little thickening type, the adventitious roots hardly developed. On the other hand, in spite of Chinese milk vetch and clovers belonging to the extensive thickening type, the adventitious roots did not developed. This would be related to the root system with big and deep tap root.