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Volume 48 (2003)
- Issue 4 Pages 211-
- Issue 3 Pages 109-
- Issue 1-2 Pages 1-
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Volume 48, Issue 3
Displaying 1-7 of 7 articles from this issue
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Shigeya Yamakawa, Min Wang, Hirofumi Yamaguchi2003 Volume 48 Issue 3 Pages 109-116
Published: October 10, 2003
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn order to learn the ecological characteristics of B. echinosperma, a threatened aquatic species, we assessed its amount of emergence, water availability and types of herbicides used in the paddy-fields of Kii-Ooshima island. We also monitored its annual phenology, changes in the number of young, middle and flowering mature plants, and the traits of reproductive capacity in a paddy field densely inhabited by this species. B. echinosperma was found to be dominant in submerged paddies, with high density, regardless of herbicide application, sub-dominant in semi-submerged paddies, and rare in well -drained paddies. B. echinosperma seedlings started to emerge in early June, two weeks after the emergence of harmful weeds. Seedlings continued to emerge throughout June, and a larger number of plants were observed from June to September. Many small seedlings emerged from the bare-soil surface in September after rice harvest, and the maximum number of plants was observed in October. Well grown, larger plants with more than 30 leaves started to flower in the middle of July, and the smaller plants with less than 29 leaves began to flower after that. The number of fruits per plant increased gradually from August to October. The number of seeds per fruit was associated with fruit length, and the total number of seeds per individual was strongly associated with plant size. Small plants emerged after rice harvest, like large plants emerged at early season, produced mature fruits in mid-autumn. This continuous fruiting throughout the season may contribute to the increase of buried seeds in rice paddies. It is highly probable that these reproductive features and the seed bank establishment play an important role in the adaptive strategy of this plant in the disturbed habitats of ill -drained paddies.View full abstractDownload PDF (861K) -
Shimpei Uraguchi, Izumi Watanabe, Katsuji Kuno, Yoshinobu Hoshino, Yos ...2003 Volume 48 Issue 3 Pages 117-129
Published: October 10, 2003
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSWe evaluated allelopathic activity of leaves of floodplain vegetation species collected from the floodplain of the middlecourse of the Tama River, where the invasion of alien plants and decline of floodplain endemic plants are remarkable, by the sandwich method using lettuce (Lactuca sativa L., Great Lakes 366) as the receptor plant. Dominant aliens in the floodplain, such as Robinia pseudoacacia L., Sicyos angulatus L. and Ambrosia trifida L., and dominant endemics such as Pueraria lobata (Willd.) Ohwi, Salix integra Thunb. and Miscanthus sinensis Anderss. exhibited strong activity. We sand-cultured Aster kantoensis Kitam., an endangered floodplain endemic plant, and 10 species distributed characteristically around A. kantoensis for 1.5 to 2 months after seeding. Then we evaluated the allelopathic activity of these plants by the sandwich method for leaf activity, and the plantbox method for root activity. All alien plants around A. kantoensis except Erigeron canadensis L. displayed strong activity in both leaves and roots. These results indicate the probability that the allelopathy of dominant alien plants is involved in their invasion and domination.
As leaves and roots of A. kantoensis also exhibited strong activity, the soil sickness that is often observed in A. kantoensis populations over 10 years old might be due to its allelopathic effect. Leaves of other floodplain endemics such as Artemisia capillaries Thunb. and Potentilla nipponica Th. Wolf collected from the Tama River, didn't displayed strong activity.
Allelopathic activities of floodplain vegetation species of the Tama River could vary with specific conditions as high soil pH, as well as growth stages of plants. It is quite important to clarify the effect of those elements against allelopathic activity as well as the relationship between succession and allelopathy in floodplain vegetation.View full abstractDownload PDF (1678K) -
Mitsuyoshi Suzuki2003 Volume 48 Issue 3 Pages 130-139
Published: October 10, 2003
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSixteen main upland weeds seeds (i. e, Stellaria media (L.) Villars, Rumex obtusifolius L., Digitaria ciliaris (Retz.) Koeler, Echinochloa crus-galli (L.) Beauv. var. crus-galli, Commelina communis L., Pensicaria lapathifolia (L.) S. F. Gray, Pensicaria longiseta (De Bruyn) Kitag., Pensicaria vulgaris Webb et Mog., Chenopodium album L., Amaranthus lividus L., Portulaca olenecea L., Rorippa islandica (Oeder) Boed., Acalypha australis L., Cerastium glomeratum Thuill., Senecio vulgaris L., and Sonchus asper (L.) Hill) in Akita Prefecture were collected from June to October 1998 and in June 1999. These seeds were buried 15cm below the soil surface in the same year. The germination characteristics exhibited in the secondary dormancy were investigated by digging up the buried seeds after winering or burying every 1 to 2 months.
The results were as follows.
1. Weed species that exhibited clear secondary dormancy in the first year and secnd year after burying were Pensicaria lapathifolia (L.) S. F. Gray, Pensicaria vulgaris Webb et Mog., Echinochloa crus-galli (L.) Beauv. var. crus-galli, and Commelina communis L.
2. Weed species that exhibited clear secondary dormancy in the first year after burying but not in the secnd year were Pensicaria longiseta (De Bruyn) Kitag. and Rorippa islandica (Oeder) Boed.
3. Weed species for which secondary dormancy was not recognized were Rumex obtusifolius L., Chenopodium album L., Amaranthus lividus L., Portulaca olerecea L., Stellaria media (L.) Villars, Cerastium glomeratum Thuill., Senecio vulgaris L., and Sonchus asper (L.) Hill.
4. Weed species for which the secondary dormancy was not clear were Acalypha australis L. and Digitaria ciliaris (Retz.) Koeler. 5. There was a tendency for seeds with secondary dormancy such as Echinochloa cnusgalli (L.) Beauv. var. crus-galli to have less longevity than species without the secondary dormancy such as Chenopodium album L. therefore, the relationship between longevity and dormancy was not clear.View full abstractDownload PDF (1284K) -
R. Miura, M. Doi, M. Yoshino2003 Volume 48 Issue 3 Pages 140-142
Published: October 10, 2003
Released on J-STAGE: December 17, 2009
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Hirohiko Morita, Tomoko Nishida, Misako Ito, Bruce Auld, Peter Michael2003 Volume 48 Issue 3 Pages 143-154
Published: October 10, 2003
Released on J-STAGE: December 17, 2009
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Jun Ushiki, Shinichi Shirakura, Masayuki Hattori, Mitsuhiro Matsuo2003 Volume 48 Issue 3 Pages 161-165
Published: October 10, 2003
Released on J-STAGE: December 17, 2009
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Hirohiko Morita2003 Volume 48 Issue 3 Pages 166
Published: October 10, 2003
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (91K)
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