Studies on the Emergence of Rice Seedlings in the Direct-Sowing Culture. : 1. On the elongation of plumule through soils after germination.

[摘要] In order to make clear the process of the emergence of plumule in the direct-sowing on dry fields, elongation of plumule through soils after germination was studied. 1) The rate of emergence of plumule decreased with the increase of seeding depth of soil covering. In the case of 5 cm-seeding-depth, the more the amount of larger clods, the more the number of plumules perished under ground. 2) The growth of the plumule of 3 cm-seeding-depth plot and that of darkness was more rapid than those of 5 cm-and 7 cm-seeding-depth plots. In this case, somewhat positive correlation exists between the time of the emergence of leaves from coleoptile and the growth of the plumule. 3) The elongation of plumule was affected by temperature. In the plot of 5 cm-depth of seeding, the number of days from seeding to emergence of plumules at 30°C, 25°C and 20°C were 5∼6, 8∼9, and 11∼12 days respectively. 4) The elongation of plumule was also affected by the hardened texture of the seed bed. When the soil covering was conducted with larger clods, the degree of the inhibitive effects of soil moisture content (130∼100 per cent soil moisture content of field moisture capacity) on the emergence was decreased.

[学科分类] 农业科学（综合）