2005 Fiscal Year Final Research Report Summary
Study on promotive effects of rice on seed germination of Potenderiaceae paddy weeds
| Project/Area Number |
15380012
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Crop science/Weed science
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| Research Institution | Utsunomiya University |
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Principal Investigator |
TAKEUCHI Yasutomo Utsunomiya University, Center for Research on Wild Plants, Professor, 野生植物科学研究センター, 教授 (90008003)
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| Co-Investigator(Kenkyū-buntansha) |
YONEYAMA Koichi Utsunomiya University, Center for Research on Wild Plants, 野生植物科学研究センター, 教授 (00114174)
YOKOTA Takao Teikyo University, School of Science and Engineering, 理工学部, 教授 (40011986)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Potenderiaceae / Monochoria vaginalis / Rice / Stimulation of seed germination / Stimulants for seed germination / Stimulation of emegence / nitrogen-fertilizer |
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| Research Abstract |
Monochoria vaginalis var. plantaginea and Heteranthera limosa are very serious aquatic weeds in paddy fields. In recent years, they became a more serious problem in Japan where the number of the weeds was increased by the method of transplanting : direct-seeding and infant-seedling culture.
This study was conducted to determine the effects of rice seeds, seedlings, hulls and straw on the germination of the weed seeds, and the following results were obtained.
The emergence of M.vaginalis was promoted by the rice seeds, straw, hulls, and bran under submerged condition. The germination of the M.vaginalis seeds was stimulated in the dark by rice seeds, hulls and straw regardless of the cultivars tested. The germination and emergence of H.limosa were also promoted by rice seeds, hulls and straw.
The aqueous residues extracted from rice straw, bran and hulls stimulated the seed germination of M.vaginalis in the dark. The stimulants seem to have replaced light. Amino acids (23 compounds) and phosphoric acid were isolated from rice straw as the candidate compounds for the stimulants. When the amino acids and phosphoric acid were mixed, they induced the seed germination in the dark. However, the mixture did not induce the germination of the sterilized seeds. These results suggest that stimulants produced by rice straw induce the seed germination possibly through enhancing the growth of microbes, which may play important roles in the seed germination.
The emergence of M.vaginalis was promoted by urea and ammonium-nitrogen. Urea and rice seeds synergistically increased the number and growth stage of the seedlings.
Fluridone and norflurazon, carotenoid biosynthesis inhibitors, promoted the emergence of M.vaginalis. They broke the seed dormancy and prevented the seeds from entering dormancy, thus these compounds can be usefull in decreasing the number of seeds in the seed bank.
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