STUDIES OF PROMOTIVE EFFECTS OFRICE PLANTS ON GERMINATION AND GROWTH OF PADDY WEEDS

本研究旨在阐明水稻种子和秧苗对日本一年生杂草之一--阴道单胞菌萌发和生长的影响。在10月下旬收获种子时，由于种皮机械限制和种胚休眠，种子在有无淹水的光照或黑暗条件下不能萌发。这些种子是3月初在一块稻田里采集的。由于冬季暴露在低温下，胚胎的休眠被打破。种子干燥后在5ﾟC条件下贮藏2~3个月。淹水条件下种子在光照下萌发，淹水或不淹水条件下种子在黑暗中不萌发。当种皮被刺穿靠近胚根的地方时，种子在光照和黑暗中萌发，没有淹水。无论有没有淹水，生长素、赤霉素、细胞分裂素、乙烯或油菜素在黑暗中都不能诱导种子萌发，但…在没有淹水的情况下，在光照下用乙烯诱导种子萌发。在温室和水田条件下，研究了水稻种子和秧苗对稻纵卷叶蝉萌发和生长的影响。2~3叶期的水稻种子和秧苗促进了杂草的萌发和生长。相反，4~5叶期的秧苗对杂草的萌发没有促进作用，反而抑制了杂草的生长。无芒藜种子和香附的种子不能促进单白草种子的萌发和生长。将种子与水稻种子在黑暗中浸泡培养皿中培养，诱导种子萌发。对水稻种子中阴道单胞菌发芽促进剂的分离进行研究。对水稻种子水提物进行了溶剂分配、ODS柱层析、凝胶过滤和离子交换柱层析。刺激剂(S)似乎是相对低分子量的高度水溶性阳离子化合物(S)。较少

This study was conducted to clarify the effects of rice seeds and seedlings on germination and growth of Monochoria vaginalis, one of the troublesome annual weeds in Japan. When the seeds were harvested in late October, the seeds did not germinate in the light or dark with or without submerged condition because of mechanical restriction of the seed coats and the dormancy of embryo. The seeds were collected in a paddy field in early March. The dormancy of the embryo was broken as a result of exposure to low temperatures during the winter. The seeds were dried and stored 2 to 3 months at 5ﾟC.The seeds germinated in the light under flooded condition, on the other hand they did not germinate in the dark under flooded or nonflooded conditions. When the seed coats were punctured near the radicle, seeds germinated in the light and dark without flooding. Seeds germination was not induced by auxins, gibberellins, cytokinins, ethylene or brassinosteroids in the dark with or without flooding, but … More the germination was induced by ethylene in the light without flooding. Seed germination was also induced by cotylenins in the dark without flooding.Effects of seeds and seedlings of rice on germination and growth of Monochoria vaginalis were studied in a greenhouse and in a paddy field. Rice seeds and seedlings at 2 to 3 leaf-stage promoted the germination and growth of the weed. In contrast, rice seedlings at 4 to 5 leaf-stage did not promote the germination of the weed and on the contrary, inhibited the growth. Seeds of barnyardgrass (Echinochloa oryzicola) and tubers of Cyperus serotinus did not promote the seed germination and growth of Monochoria vaginalis. When the seeds were incubated with rice seeds in petri-dish in the dark with flooding, the germination was induced.Study was conducted to isolate Monochoria vaginalis germination stimulants in rice seeds. Water extracts of rice seeds were subjected to solvent partitioning, ODS,gel filtration and ion-exchange column chromatographies. The stimulant (s) appeared to be highly water soluble cationic compound (s) of relatively low molecular weights. Less