Physiological and Ecological Studies on Barnyard Grass (Echinochloa crus-galli Beauv. var. oryzicola Ohwi) : V. On the germination of the seed.

[摘要] The emergence of barnyard grass seeds is divided into two processes, that is, germination in soils and elongation of plumule through soils after germination. The former process was studied in the present report. 1) Maximum, optimum and minimum temperatures for germination were 45°C, 30°to 35°C and 10°C to 15°C respectively. The completely after-ripened seeds were not accelerated under the alternating temperature condition. 2) The seeds were able to germinate with pH ranging from 4.7 to 8.3. So, it was concluded that this plant was adaptable to soil acidity for the germination. 3) Oxygen tension of 20 per cent (air) was favorable for germination. But, germinaion percent was decreased in the oxygen tension below 1 per cent. 4) Germination did not occure in water contained 1×10-3M KCN and NaN3, while not affected DICA, MIA and 8-hydroxyquinoline. Therefore, we thought that cytochrome oxidase played an important role in the process of germination of barnyard grass seeds. 5) Soil water content influenced the germination of the seeds, and 70 to 95 per cent soil moisture content of field capacity was optimum for germination. 6) Germination per cent of the seeds in the submerged soil varied with Eh values of the soil. In the below 350 to 400 mV of Eh6 of the soil, germination per cent decreased according to the fall of Eh value, and hardly germinated in the soils below 100 mV of Eh6. 7) As the results of these findings, germination of seeds were good in the field of the wet upland condition (above 70 per cent soil moisture content of field capacity) in which Eh value was kept high. And, dry upland soil condition and submerged soil condition with low Eh value were unfavorable to germination.

[学科分类] 农业科学（综合）