作物の養分吸収に関する動的研究(第3報) : 亜硫酸の生成より見たる作物根の還元力と生育期

抄録

In the course of some dynamic studies on the nutrient uptake by 7crop plants the reducing power of the roots of growing plants as revealed by nitrite formation in the nutrient solution was determined through the whole periods of growth. The results may be summarized as follows. 1. As seen from Table 2 & 3 the accumulation of nitrite nitrogen by seedling of crop plants increased gradually as the days passed, although its amount was scarce in generaland for lowland rice and taro it was o〜trace indicating some oxidative power of their roots as contrasted to other crop. 2. Fig. 1-12 and Table 3 show the general trend of nitrite formation of 13 kinds of crop through their complete growth periods. For cereals such as lowland rice, upland rice, corn, kaoliang, wheat, barley and rye it began to increase about one month before heading (period of elongation), attained its maximum at flowering or heading followed by gradual or sudden decrease to maturing stage. The lowland rice, one of the typical aquatic plant, was by no means exception. Rape showed similar trend as cereals, but the maximum was attained far later from the flowering stage. Taro, which is said to prefer near aquatic soil humidity and usually reproduces without flowering, behaved peculiar, the feeble nitrite formation gradually increasing without any peak until its harvest time was reached. 3. The mechanism of nitrite formation will be discussed in the next report, but the result was discussed on some agronomical meanings, for instance, the possible contribution of the reducing power of the roots of lowland rice and wheat and barley at their vigorous growth to the enhanced injury of hydrogen sulfide and of the too high water level respectively. Moreover, the increasing phosphate absorption in the spring time in many winter cereals as experienced by fertiliser experimenters might well be partially explained by the increasing reducing power of the roots of the cereals at this period by which partial reduction of ferric to ferrous-the increase in phosphate solubifity-in the rhizosphere is meant.