ヒエ属植物およびイネの種子の発芽に及ぼす塩分、蔗糖、PEG溶液の浸透圧の影響

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.

干拓地、塩害地における雑草の発生、植物の対塩生機構の解明の一端として、水田強害草の野生ヒエの塩分に対する発芽反応の研究を行った。水田で発芽生育する作物のイネは塩分による発芽の阻害は浸透圧の増大によるところが大きいことを示した。一方、雑草のヒエは概して浸透圧による発芽の阻害は塩分、蔗糖によって回復される傾向を示し、特に変温条件下の塩分でイヌビエ種の発芽の阻害が相当程度回復することを示した。これは野生ヒエ、特にイヌビエが自然状態の塩分の比較的多いところにでもそれに適応して発芽可能なことを暗示しているものと考えられる。