Allelopathic Potential of Rice Seed (Oryza sativa L.) on Seed Germination of Monochoria vaginalis var. plantaginea.

Abstract

Laboratory experiments were performed to evaluate the effect of germinating rice seeds (Oryza sativa L.) on seed germination of Monochoria vaginalis (Burm. f.) Presl var. plantaginea (Roxb.) Solms-Laub (here-after Monochoria). Rice seeds (cv. Tsukinohikari) promoted the seed germination of Monochoria at all incubating temperatures except 31°C, an optimal temperature for germination of Monochoria in the light. In darkness, although under non-inductive conditions for germination of Monochoria, rice seeds dramatically induced the seed germination at all incubating temperatures. Such stimulative effects of rice seeds were observed with both nondormant and dormant seeds of Monochoria harvested in different years. Furthermore, seeds of all 12 rice cultivars tested in the experiments exhibited a stimulative effect on the seed germination of Monochoria. Ethylene and carbon dioxide released from rice seeds and seedlings seemed to be involved in the promotion of this germination. Stimulative allelochemical (s) in rice seeds or seedlings may also promote the seed germination of Monochoria.