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Volume 40 (1995 - 199･･･
- Issue 4 Pages 245-
- Issue 3 Pages 157-
- Issue 2 Pages 69-
- Issue 1 Pages 1-
- Issue SupplI Pages 2-
Volume 40, Issue 3
Displaying 1-13 of 13 articles from this issue
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Akio Hongo1995 Volume 40 Issue 3 Pages 157-162
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
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Fan Deng, Kenji Usui, Kozo Ishizuka1995 Volume 40 Issue 3 Pages 163-171
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe growth and glutathione S-transferase (GST) activities of rice and early watergrass seedlings as affected by pretilachlor and/or fenclorim were investigated, especially in early growth stages.
After the seeds were treated with pretilachlor for one week, the I50 value in rice was higher than that of the early watergrass. The inhibition of growth by pretilachlor treatment to seeds was reversed in the rice by fenclorim treatment but not in the early watergrass seedlings. The effects of pretilachlor were similar to the seed treatment, but fenclorim reversed the growth inhibition caused by pretilachlor treatment in the two plants of 1-leaf-stage.
GST(pret.) activities of both plants increased progressively with growth from 0.5- to 2-leaf-stage, although these activities were higher in rice. As the plant grew, however, difference in GST activities between two plant species lessened. GST(pret.) activities in rice were increased with individual or simultaneous treatments of fenclorim (2×10-5M) and pretilachlor (10-5 or 10-4M); the activities in early watergrass were increased mainly with the simultaneous treatment at the seed and 1-leaf-stage. GST activities of both plants varied with different substrates, i. e., pretilachlor and CDNB. Differences in GST(pret.) activities might explain the selectivity between rice and early watergrass of pretilachlor. Moreover, the recovery from growth inhibition caused by pretilachlor might be due to induction of GST enzyme by fenclorim.View full abstractDownload PDF (1032K) -
Fan Deng, Kenji Usui, Ie Sung Shim, Katsuichiro Kobayashi, Kozo Ishizu ...1995 Volume 40 Issue 3 Pages 172-178
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSome properties such as molecular weight, pH optima, Km, Vmax and substrate specificity of glutathione S-transferase (GST) from rice and early watergrass seedlings were characterized.
The molecular weight of GST catalyzing pretilachlor (GST(pret)) or CDNB (GST(CDNB)) with reduced glutathione (GSH) was almost the same in the two plant species and calculated to be about 52, 000 dalton (Fig. 1). The optimum pH value of GST(pret) in both rice and early watergrass was pH 6.5 (Fig. 2).
The Km of GST(pret) for pretilachlor and glutathione (GSH) was similar in both plants. On the other hand, the Vmax value of GST(pret) from rice was about 1.5 times higher than that from early watergrass (Table 1). The Km values of GST(pret) decreased while the Vmax value increased when pretilachlor and/or fenclorim were applied to rice seedlings at the 2-leaf stage for 24 hours. In the case of early watergrass, however, the combination of pretilachlor and fenclorim only led to the decrease the Km(GSH) value and increase of the Vmax value. When CDNB or fenclorim was added in vitro, the GST(pret) activity of rice decreased by 0-22% or 6-39%, respectively, and by 0 or 0-43% in early watergrass, regardless of whether the plants were pretreated with pretilachlor or fenclorim (Table 2).
It is suggested that in rice the substrate specificity of GST is different from that of early watergrass. Furthermore, selectivity of pretilachlor between rice and early watergrass may be related to GST(pret) activity and induction of GST(pret), and the safening effect of fenclorim may also be related to the induction of GST(pret).View full abstractDownload PDF (768K) -
Reiichi Miura, Hisao Kobayashi, Tokuichi Kusanagi1995 Volume 40 Issue 3 Pages 179-186
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSStellaria media (L.) Vill. is an annual agrestal weed often infesting horticultural fields, whereas S. neglecta Weihe grows in ruderal habitats such as roadsides and forest margins. Field censuses were carried out in representative habitats of the two species to compare their germination strategies. In vegetable and vine gardens, S. media individuals emerged after tillage from spring to autumn, and started flowering about 30 to 40 days after emergence. The cohorts that emerged earlier after tillage had larger plant size and higher survivorship to flowering than later-emerging ones. This trend suggests a potential selection pressure favoring quicker emergence after tillage. In ruderal habitats, S. neglecta individuals emerged in autumn, grew through the winter, flowered in the following spring and died before summer. The cohorts that emerged earlier in autumn suffered higher mortality, probably due to shading by summer plants and herbivory, but attained larger plant size if they survived. This trade-off between survivorship and plant size seems to determine the optimal emergence time in autumn.View full abstractDownload PDF (905K) -
Kenji Usui, Tosapon Pornprom, Hiroshi Matsumoto, Shinichi Shirakura, K ...1995 Volume 40 Issue 3 Pages 187-193
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSCharacterization of cross-tolerance of selected oxyfluorfen-tolerant and non-selected (normal) soybean cell lines to protoporphyrinogen oxidase (Protox) inhibiting herbicides (oxyfluorfen, 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene; bifenox, methyl 5-(2, 4-dichloro-phenoxy)-2-nitrobenzoate; nitrofen, 2, 4-dichloro-1-(4-nitrophenoxy) benzene; and oxadiazon, 3-[2, 4-dichloro-5-(1-methylethoxy) phenyl]-5-(1, 1-dimethylethyl)-1, 3, 4-oxadiazol-2-(3H)-one) or acetolactate synthase (ALS) inhibiting herbicide (bensulfuron-methyl, methyl α-[[3-(4, 6-dimethoxypyrimidin-2-yl) ureido] sulfonyl]-o-toluate, BSM) was determined. The sensitivities of both cell types to oxyfluorfen were compared by determination of the growth rates and target enzyme inhibition using various Protox inhibiting herbicides. On the I50 values of growth, the tolerant cells showed about 100-, 200-, 5, 000-, and >30, 000-fold more tolerance than the normal cells to oxyfluorfen, oxadiazon, bifenox, and nitrofen, respectively. The cells were found to have cross-tolerance to all Protox inhibiting herbicides tested, however, a lack of cross-tolerance (<1.0) to BSM was observed. Determination of the inhibition on Protox activity showed that the sensitivity of the enzyme preparations between the two cell types differed about 15-fold to oxyfluorfen, 30-fold to oxadiazon, 45-fold to bifenox, and 100-fold to nitrofen. There was a positive correlation between the tolerance ratio determined by growth rate and that at the enzyme level.View full abstractDownload PDF (724K) -
Motoaki Asai, Misako Ito, Tokuichi Kusanagi1995 Volume 40 Issue 3 Pages 194-202
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSTo determine the optimal mowing regime for the maintenance of two cultivars (Grasslands Huia and California Ladino) of white clover sod and its weed suppression, field trials were conducted for two years beginning in 1991. Sixteen mowing regimes were evaluated: all combinations of frequency and time of mowing 4 times a year, spring (mid April or early May), June, August and October. During the first year, mowing regimes little affected clover growth and the vegetation dynamics, but in the second year they significantly affected them. Clover coverage declined in the summer of 1993 because of the depression of clover growth and weed invasion caused by creation of a gap after mowing. June mowing, in particular, induced emergence of large summer grasses, e. g., Setaria faberi and Digitaria ciliaris, which suppressed clover. Mowing in August and October increased emergence of winter annuals, while June mowing increased that of summer annual weeds. The winter annuals were not noxious, but some summer grasses had adverse effects on clover. Regardless of mowing, Rumex spp. and Lolium multiflorum increased their dominance ratio in all the treatments. ‘Ladino’ exhibited more continuous dense cover and superior weed suppression than ‘Common’. Mowing at other than ‘spring flush’ stage should be avoided to maintain established clover sod.View full abstractDownload PDF (1000K) -
Masayuki Nemoto, Kyoichi Shibuya, Masahiko Saigusa1995 Volume 40 Issue 3 Pages 203-208
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn the past, common comfrey (Symphytum officinale L.) was cultivated extensively in Japan for medicinal use, as well as for use as a vegetable and feed of domestic animals in the 1960's. In recent years, however, due to the reduced demand for common comfrey production, the plant has tended to remain in crop fields and to behave like a weed.
1) Individuals of common comfrey which exhibit various sizes and growing stages formed a dominant population in the field surveyed. Within this population the height and the area occupied by each plant in the reproductive stage tended to be barger than in the vegetative stage (Fig. 1).
2) The common comfrey plants which emerged in the field were derived from the buried root fragments remaining in the soil of this field. The fragments can be divided into two types: fragments with or without a crown (Fig. 2). The former developed to the reproductive stage, while the latter remeined in the vegetative stage and in some of them the top of the leaf bud did not sprout on the soil surface (Fig. 3).
3) Plant size of common comfrey emerging from former ridges was relatively larger than that from the former furrows. The position of the root fragments under the former ridges was shallower in soil than that under the former furrows (Fig. 4). The proportion of the newly formed underground organs (NUO) to the whole new organs (WNO) was calculated and a positive correlation between NUO/WNO and depth of buried old root fragments was recognized (Fig. 5).View full abstractDownload PDF (684K) -
Shizuko Ishikawa, June Abe1995 Volume 40 Issue 3 Pages 209-214
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSGenerally, the trait for seed germination is strongly associated with the persistence of weed species under disturbed conditions. Seeds of Capsella bursa-pastoris collected in an orchard exhibited a very wide variation in germination time. Such a pattern of seed germination appeared to be advantageous under unpredictable environmental conditions, because the replacement of seedings was secured.
To analyse the factors controlling the even germination of Capsella bursa-pastoris, analysis of variance of nested design was conducted for the germination behavior, using 12 seed families. These ANOVAs partitioned phenotypic variance in each trait into components associated with families, plants within families and two age classes, immature yellow seeds and mature brown seeds, within plants. Yellow seeds germinated more slowly than mature seeds, but the differences between age classes was not statistically significant. On the other hand, there were significant differences among families in the germination rate, germination time (GT) and coefficient of variance for GT. These differences suggest that genetic diversity for seed germination may play an important role in the occurrence of Capsella bursa-pastoris in the orchard.
Since the germination of buried seeds was enhanced by the disturbance of the soil surface, it is suggested that environmental factors also affect the germination pattern of Capsella bursa-pastoris.View full abstractDownload PDF (597K) -
Masaru Ogasawara, Shin-ya Kitamura, Koichi Yoneyama, Yasutomo Takeuchi ...1995 Volume 40 Issue 3 Pages 215-217
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
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Shinichi Shirakura, Kenji Ito, Hiroyasu Aizawa1995 Volume 40 Issue 3 Pages 218-220
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
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Yasutomo Takeuchi, Takesi Sassa, Shun Kawaguchi, Masaru Ogasawara, Koi ...1995 Volume 40 Issue 3 Pages 221-224
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
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1995 Volume 40 Issue 3 Pages 232-235
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
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Soichi Nakayama, Tomoko Shibuya, Yoshiaki Kawana, Yasuhiro Yogo1995 Volume 40 Issue 3 Pages 236-240
Published: October 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (578K)
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