Journal of Weed Science and Technology
Online ISSN : 1882-4757
Print ISSN : 0372-798X
ISSN-L : 0372-798X
Volume 54, Issue 2
Displaying 1-7 of 7 articles from this issue
Original Reports
  • Ken-ichi Matsushima, Fujio Tamai, Katsuyoshi Noguchi, Tomoji Hirose, M ...
    2009 Volume 54 Issue 2 Pages 55-62
    Published: 2009
    Released on J-STAGE: July 08, 2009
    JOURNAL FREE ACCESS
    The regrowth response and seed-production capability of Asiatic plantain (Plantago asiatica L.) plants after cutting was examined in comparison with those of other native plants. Native plants used were Goosegrass (Eleusine indica (L.) Gaertn.), Common purslane (Portulaca oleracea L.), Southern crabgrass (Digitaria adscendens (H.B.K.) Henr.), Japanese mugwort (Artemisia princeps Pampan) and Cogongrass (Imperata cylindrica (L.) Beauv.), which grow near farm areas.
    The following results were obtained.
    Four weeks after cutting, Asiatic plantain plants of 3cm cutting height had an almost equal number of leaves to those produced by plants in a no-cutting treatment. However, the Goosegrass leaf quantity was 72%-the other four species’ leaf numbers were 67% or less-compared to the respective no-cutting treatments. Moreover, results showed that the type of regrowth differed among species in the case of cutting height at the ground surface:Asiatic plantains regrew with leaves emerging from the cut main stem;other species regrew mainly with shoots emerging from their branches and axillary buds. The leaf emergence rates of Asiatic plantains sown in May and cut in July or August were higher than in no-cutting plants. Results show that the number of leaves recovered to pre-cutting quantities by 28 days after cutting;the number became equal to that of leaves in no-cutting plants by 40 days after cutting. Moreover, inflorescence production of the cut plants started from 30-40 days after cutting. By about 50 days after cutting, inflorescence production was not inferior to that of no-cutting plants. Taken together, these results demonstrate that Asiatic plantain plants promptly reproduce the assimilatory organ by increasing the leaf emergence rate from the main stem, even if aerial parts are cut during the growth period, which enables seed production for the next generation.
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  • Koji Yoshida, Yumiko Kanazawa, Kojiro Suzuki, Masayuki Nemoto
    2009 Volume 54 Issue 2 Pages 63-70
    Published: 2009
    Released on J-STAGE: July 08, 2009
    JOURNAL FREE ACCESS
    The role of seed germination characteristics in facilitating the rapid acclimation of the exotic long-headed poppy (Papaver dubium) in Japan was assessed using indoor and outdoor cultivation experiments. Results of outdoor experiments showed that seeds sown in June germinated in the fall of the same year and the following spring. Indoor germination experiments, conducted using seeds stored under different temperatures and moisture conditions, revealed that seed germination rates were highest under the following conditions:(1) moist, warm conditions for 2 to 3 months followed by storage at 5°C, (2) moist, warm conditions for 3 months followed by storage under moist, cold conditions for half month to a month and then at 10∼20°C, and (3) storage for three months under varying temperature and moisture conditions. These outdoor and indoor germination experiments confirmed that seeds germinated under natural environmental conditions in the fall when temperatures decreased relative to the moist warm conditions of summer and in the subsequent spring when the temperatures increased after the cold winter months. Seed germination in seeds stored at high or room temperatures, under dry conditions for approximately three years, or under dark conditions, was relatively lower. Consequently, seeds that become buried in the ground are likely to remain dormant for extended periods of time. In addition, the optimal germination temperatures for the longheaded poppy observed in this study closely match the meteorological conditions of the numerous regions, both domestically and internationally, where this species is found.
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  • Hidehiro Inagaki, Youichi Kida, Yoshiki Ishida, Motoaki Asai, Minoru I ...
    2009 Volume 54 Issue 2 Pages 71-76
    Published: 2009
    Released on J-STAGE: July 08, 2009
    JOURNAL FREE ACCESS
    In order to establish an integrated weed control system for Italian ryegrass, which causes serious weed damage to wheat crops in Chuen area, Shizuoka, we conducted a field experiment and determined the effect of tillage and non-tillage treatments on the seedling emergence of the weed. The non-tillage of soil for soybean cropping resulted in an increase in Italian ryegrass emergence in the summer. In the subsequent wheat-cropping season, emergence did not decrease when compared to the emergence using the conventional tillage system. The lowest emergence was observed with a combination of tillage for soybean cropping and non-tillage for wheat cropping. For wheat cropping, the soil hardness was greater and the depth distribution of seeds that produced seedlings was shallower in the non-tilled soils than in the tilled soils. It is supposed that the combination of tillage for soybean cropping and non-tillage for wheat cropping is effective for the suppression of Italian ryegrass because the seeds of this weed are buried with tillage in the summer and the emergence is inhibited in the non-tilled and hardened heavy clay soil conditions in the winter.
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  • Mitsuhiro Matsuo, Miyo Sakamoto, Shiori Takasago, Shuichiro Homma, Hir ...
    2009 Volume 54 Issue 2 Pages 77-85
    Published: 2009
    Released on J-STAGE: July 08, 2009
    JOURNAL FREE ACCESS
    The differences in the germination, growth, and production of four seed types, large or small, aerial or subterranean, and in the emergence of two seed types, large or small subterranean, on tropical spiderwort (Commelina benghalensis L.) distributing in southern Kyushu Island, southwestern of Japan, were observed. The large aerial and subterranean seeds germinated higher at temperatures of 25 to 40°C, and the mean germination days were 3 to 4 days at a temperature of 30 to 40°C. The coefficient of uniform germination on the large aerial and subterranean seeds were 0.7 to 1.1 at a temperature of 30 to 35°C. The small aerial and subterranean seeds germinated higher at temperatures of 30 to 35°C, but the values of mean germination days and coefficient of uniform germination were longer and lower than those of the large aerial and subterranean seeds did, respectively. The seedlings from large aerial and subterranean seeds emerged the most from March to May. However, those from small aerial and subterranean seeds exhibited higher emergence intermittently from April to September. Seedlings from large aerial and subterranean seeds emerged from soil depths of 0 to 50 mm, and those from small aer-ial and subterranean seeds emerged from soil depths of 0 to 10 mm. Although the ratio of leaf length to leaf width in the first completely developed leaf blades is about 1.45 in all types of seeds, the leaf width of the seedlings was significantly different among the four seed types. The plant length, numbers of primary branches and leaves, and fresh weight of aerial parts of the plants obtained from the four seed types were almost the same. Furthermore, the numbers of spathes, and large and small aerial and subterranean seeds produced in those plants were also the same.
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  • Yuko Suto, Takuya Abe, Masaru Ogasawara
    2009 Volume 54 Issue 2 Pages 86-95
    Published: 2009
    Released on J-STAGE: July 08, 2009
    JOURNAL FREE ACCESS
    The present study was conducted to investigate seed banks, which are a source of weed seeds, in seams of curbside by the side of Route 4 from Oyama City in Tochigi Prefecture to Shichinohe Town in Aomori Prefecture. Weed vegetation on the verges and around the roads was surveyed at 24 points from June 6 to 9 and from September 22 to October 4, 2007. Soils were also sampled from the verges at the same time. After the soils were air-dried and passed through a φ5 mm sieve, the weed species and the number of seeds were examined. Seed viability was measured by the press method using forceps.
    The results obtained from the study are summarized as follows:1) seed banks were formed in all verges of the road, 2) Seeds of Digitaria ciliaris, Setaria viridis, Taraxacum spp., and Oxalis spp. were abundant in the soil samples, 3) although Plantago asiatica and Artemisia princeps were dominant in the verges, no seeds of either weed species were found in the soils, 4) sources of seeds detected in the soil samples differed according to weed species. For example, seeds of Digitaria ciliaris are supplied from the vegetation of the verges and/or the roads around, whereas many seeds of Sonchus asper are carried over long distances by the wind, and 5) seed viability was high (more than 60%) in Cerastium glomeratum, Oxalis spp., Arenaria serpyllifolia, Poa pratensis, and Senecio vulgaris and low in Digitaria ciliaris and Taraxacum spp.
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