The Effect on Germination of Some Species of the Genus Echinochloa and Rice Seeds with Various Osmotic Pressure of Salt, Sugar, and PEG Solutions

To investigate the differences and mechanism of germination among the seeds of some species of genus Echinochloa and rice, the experiments were conducted in solutions of salt, sugar, and PEG(poly-ethylene glycol) under a constant or alternating temperature in the light or the dark. The seeds of Echinochloa oryzicola Vasing., Ehinochloa crus-galli Beauv.var. formosensis Ohwi, Echinochloa crus-galli Beauv.var.crus-galli(awnless and awned type)and Oryza sativa L.(Akebono) were used. In 7000hPa, germination of rice,E. oryzicola and three varieties of E.crus-galli in all the solutions remarkedly decreased except for the case of E.crus-galli in the solution of sale on alternating temperature. The germination of rice and E.oryzicola was secreased markedly, and more markedly in a light condition than in a dark. In the salt solution in 7000hPa, the decreasing of germination of E.crus-galli was low. This species is distributed and grows in the upland and paddy field, while E.oryzicola and rice grow only in the paddy field. The decreade in germination of Echinochloa species with osmotic pressure seemed to be recoverde with salt or sugar solutions under alternating temperature, but the recovery of rice was not seen. In 700hPa or less, the distinct differences of germination were not seen among these plants species.