All issues
Volume 47 (2002)
- Issue 4 Pages 229-
- Issue 3 Pages 147-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
- Issue Supplement Page･･･
Volume 47, Issue 1
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
-
Mitsuhiro Matsuo, Hidejiro Shibayama2002 Volume 47 Issue 1 Pages 1-6
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSWe investigated growth and adhering strength to the soil surface of a paddy field of Monochoria vaginalis (Burm. f.) Kunth seedlings after applying bensulfuron-methyl (BSM) and benthiocarb (BTC). Juvenile seedlings of M. vaginalis could not adhere to the paddy soil surface after soil treatment with 1ppm of BSM, but treatments with concentrations lower than 0.01ppm did not inhibit their adhesion to soil. Both lengths of their seminal roots and total crown roots after treatment with 0.0001ppm of BSM became longer than those of the untreated control (UTC) by the fifth day after seeding. There were about 100 hypocotyl hairs per seedling in seedlings treated with all concentrations, and lengths of the longest hypocotyl hair were almost the same as those of UTC on the fifth day after seeding. M. vaginalis seedlings could not grow and adhere to soil after treatment with 1ppm BTC. The growth of M. vaginalis seedlings was about the same as or a little less than those of UTC in treatments at concentrations less of than 0.1ppm. The number of hypocotyl hairs and lengths of the longest hypocotyl hair per seedling were similar for all BTC treatment concentrations compared with those in UTC for 5 days after seeding. Adhering strengths of juvenile seedlings of M. vaginalis in UTC were 2.3g, while those treated with 0.001 and 0.0001ppm of BSM were 1.8g and 2.6g at the third day after seeding. The strengths increased and became twice those of UTC on the fifth day after seeding. In BTC, their adhering strengths were less than those of UTC five days after seeding under all treatment concentrations.View full abstractDownload PDF (907K) -
Shizuko Ishikawa, Kinya Masuda, Shigehito Takenaka, Seiichi Toyota2002 Volume 47 Issue 1 Pages 7-13
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSWe investigated weed community diversity and density in direct-seeded and transplanted cabbage fields, in order to establish weed management systems for direct-seeded cabbage in the Tokachi District of Hokkaido.
In direct-seeded cabbage fields, Rorippa islandica (Oeder) Borb., Chenopodium album L., Persicaria longiseta (De Bruyn) Kitag and Parsicaria nepalensis (Meisn.) H. Gross were especially prominent. Although the composition of weed species did not differ between direct-seeded and transplanted cabbage fields, weed densities increased in direct seeding and R. islandica increased.
The cropping season and method of fertilizer application influenced the emergence of R. islandica. During the cabbage growing season, R. islandica began flowering and produced many mature seeds. Some of these seeds emerged from late summer to fall, and winter survival of fall-emerging seedlings influenced the following rotational crops.
Although soil-applied herbicide (trifluralin) successfully in the controlled common weeds, it did not control R. islandica. Results indicated that R. islandica should be considered in weed management systems for direct-seeding cabbage production in the Tokachi District of Hokkaido.View full abstractDownload PDF (933K) -
Akira Koarai, Hirohiko Morita, Masayuki Hattori, Hidejiro Shibayama2002 Volume 47 Issue 1 Pages 14-19
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSOne hundred grams of unhulled rice or 20 grams of rice hull were extracted with 1000ml water at 5°C during 48 hours. Thereafter, the water was filtered and diluted twofold with distilled water and was used for 0.5% agar culture media in plant boxes, on which seeds of Monochoria vaginalis were sown at 1mm depth. Distilled water was used for the 0.5% agar culture media in the boxes as untreated control.
M. vaginalis seeds germinated well at incubation temperatures ranging between 20 and 25°C in the agar media of the water extract of unhulled rice. The length of the seminal root was maximum at a 30°C incubation temperature in the agar media (Table 1). Seed germination rates of M. vaginalis were high in the agar media of the water extract of unhulled rice diluted two or four times (by volume), and were also high in the agar media of the water extract of rice hull diluted two times (by volume) (Table 2).
Seed germination rates and seminal root and cotyledon length of M. vaginalis were determined after the species were cultured in agar media consisting of the water extract of unhulled rice of 43 rice cultivars including Japonica and Indica types at 30 (light) -25 (dark) °C during seven days. The germination rate of M. vaginalis seeds in the agar media of the untreated control was 13.3%, while these in the agar media of the water extract of unhulled rice of all the cultivars ranged from 78.3 to 96.7%. Seminal roots of M. vaginalis seedlings elongated more in the agar media of the water extract of unhulled rice of all the cultivars except for three cultivars, compared with the media of the untreated control. Cotyledons of M. vaginalis seedlings grew longer in the agar media of the water extract of unhulled rice of all the rice cultivars than in the media of the untreated control (Table 3).View full abstractDownload PDF (845K) -
Akira Koarai, Hirohiko Morita2002 Volume 47 Issue 1 Pages 20-28
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSusceptibility of Monochoria vaginalis to bensulfuron-methyl was investigated in seeds collected in fifteen paddy fields in three Prefectures, namely Akita, Ibaraki and Gifu, in eastern Japan, where the species had been growing profusely. The susceptibility was assayed based on the effect of the application of bensulfuron-methyl on the seminal root length in agar media. M. vaginalis seedlings which germinated from seeds collected in a paddy field in Kyowa town, Akita Prefecture, and in three paddy fields in Miho village, Ibaraki Prefecture, were found to be resistant to bensulfron-methyl (Tables 1, 3, 6, Fig. 1), where a combination of sulfonylurea herbicides had been applied during more than three consecutive years (Table 4). However, the resistant biotype of M. vaginalis was controlled by mefenaset and pretilachlor in agar culture medium test (Table 5). The biotype of M. vaginalis resistant to bensulfuron-methyl displayed a cross-resistance to other sulfonylurea herbicides in Wagner pot experiments (Table 6). The application of a combination of sulfonylurea herbicides including mefenacet, pretilachlor or benthiocarb and pyrazolate enabled to control the sulfonylurea-resistant biotype of M. vaginalis effectively, when the herbicides were applied at the 1st leaf stage of the species in Wagner pot experiments (Table 6).View full abstractDownload PDF (1121K) -
Hidehiro Inagaki, Yoko Oki2002 Volume 47 Issue 1 Pages 29-32
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (424K) -
Masaru Ogasawara, N. Park, Yuko Suto2002 Volume 47 Issue 1 Pages 33-35
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (373K) -
Seiichi NISHIMURA, Kazuyuki ITOH2002 Volume 47 Issue 1 Pages 36-41
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSWe investigated concentrations of dioxins in paddy soil, green algae and paddy weeds in paddy and fallow paddy fields in the Tohoku region of Japan. Residue levels of dioxins were highest in paddy soil, where they ranged between 43, 000 and 83, 000pg/g (26-72pg/g TEQ). The next highest residue level was observed in a green algae (Pithophora zelli Wittrock) with 1, 600pg/g (0.64pg/g TEQ). In contrast, residue levels of dioxins were lower than 70pg/g (0.1pg/g TEQ) in shoots, new buds and rhizomes of paddy weeds (Sagittaria trifolia L., Bidens tripartita L., Phragmites australis (Cav.) Trin. ex Steud, Typha latifolia L. and Zizania latifolia L.) except one sample. Analysis of the isomer composition revealed that the main congener of the contained dioxins was 1, 3, 6, 8-TCDD in all samples, followed by 1, 3, 7, 9-TCDD or OCDD, which indicates that most part of the contaminated dioxins were derived from chlornitrofen formerly applied to the paddy fields. The effect of other agrochemicals and municipal solid waste incinerators was also indicated by some minor isomers such as OCDD or PCDFs. 2, 3, 7, 8-TCDD, the most toxic congener, was detected only in soil and algae samples, which amounted to less than 0.005% of the total amount of dioxins.View full abstractDownload PDF (797K) -
Yukari Sunohara, Masatoshi Gohbara, Shizuko Ishikawa, Reiichi Miura, H ...2002 Volume 47 Issue 1 Pages 46-51
Published: April 30, 2002
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (889K)
- |<
- <
- 1
- >
- >|