抄録
This experiment was conducted as a part of studies on physiological and ecological characters of paper mulberry plants. An auto-irrigating nursery bed designed by the junior author in 1941 was used to regulate the soil moisture contents. Each of five plots was kept at a different levels of moisture, 40, 50, 52, 60, and 90% of the water capacity of the soil by controlling the under ground water plane at 90, 42, 30, 20 and 10 cm below the soil surface, respectively. The sesults obtained are summarized as follows: 1) The number of sprouting root-cuttings were 9.4, 31, 2, 25, 0, 25.0 and 17.2% for 40, 50, 52, 60 and 90% moisture levels, respectively. The highest was the sprountig percentage in the plot of 50% moisture, and the lowest in the of 40%. 2) The average total length of branches per plant was 61, 3, 74.3, 100.7, 20.1 and 7.0cm for each plot, respeatively. The 52% moisture plot was of the highest value and 90% of the lowest. 3) Some disparity was found in the optimum soil moisture contents both for sprouting and growth. 4) The optimum soil moisture content for the growth of paper-mulberry as far as the authors experiments were concerned seemed to be lower than those for any of such crop plants, as cotton, flax or jute observd by other investigaters (T. SASAKI and G. NISHIKAMA 1938, K. YOSHIDA 1936, T. TAMAI and H. KATAYMA 1943), and it is particulary worth noticing that its optimum is remakably lower and narrower in range compared with that for jute. 5) Moreover its sprouting is considerably influenced by the thickness of root-cuttings, rather slender ones sprouting better than thicker ones.
