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Volume 34 (1989)
- Issue 4 Pages 273-
- Issue 3 Pages 181-
- Issue 2 Pages 87-
- Issue 1 Pages 1-
- Issue Suppl Pages 1-
Volume 34, Issue 2
Displaying 1-12 of 12 articles from this issue
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S. TAKEDA, T. YUYAMA, R. C. ACKERSON1989 Volume 34 Issue 2 Pages 87-93
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
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Yasuo TOMIHISA1989 Volume 34 Issue 2 Pages 94-100
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
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Kazuyuki ITOH1989 Volume 34 Issue 2 Pages 101-106
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
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Yoko OKI, K. R. REDDY1989 Volume 34 Issue 2 Pages 107-116
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSNineteen clones of water hyacinth were collected from different freshwater habitats of Florida (areas ranging from northwest to southeast) in order to determine the differences in productive characters. Clones obtained were characterized for parameters such as plant height, leaf area, leaf width and length, petiole length and width, photosynthetic area and shoot/root ratio by dry weight.
Since the clones obtained from the various habitats were morphologically different, one original ramet from each collection was then cultured under identical conditions (unilimited nutrient conditions) in a controlled aquaculture system. Daughter ramets produced were examined for differences in productive characters after 40 and 120 days culture. The productive characters (except shoot/root ratio) of daughter ramets showed the same variation as their respective original ramets at the time of 100% coverage (after 40 days of culture); however, after 120days, the variability among daughter ramets decreased significantly.
In a second experiment after original ramets had been cultured for about 40 days, daughter ramets produced were examined for productivity under unlimited nutrient conditions for 4 weeks. At the end of that period, net productivity of daughter ramets was significantly affected by dry weight and photosynthetic area of the parent ramet. However, this effect was gradually reduced as the new generation progressed.View full abstractDownload PDF (972K) -
Yuh-Lin CHEN, Hann-Chyuan CHIANG, Lai-Quey WU, Yei-Shung WANG1989 Volume 34 Issue 2 Pages 117-122
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIsopropylamine salt of glyphosate [N-(phosphonomethyl) glycine] was applied to control water hyacinth [Eichhornia crassipes (MART.) SOLMS] in ponds and in irrigation canals. To evaluate the dissipation of the herbicide applied, water bodies both with and without this plant were treated with glyphosate. Glyphosate was surface sprayed at the rate of 1.166kg a. e./ha in the model experiment and 1.020kg a. e./ha in the field experiments. The water hyacinth in ponds and irrigation canals was controlled at the rates applied and residue of the herbicide in the aquatic environment immediately after the treatment was found to be less than 1ppm. Moreover, glyphosate dissipated rapidly from the aquatic environment, with less than 22% of the maximum concentration remaining 1 day after the treatment in the ponds; no detectable residue was found in the canals 4hr after treatment. Glyphosate was thus concluded to be an effective and safe herbicide to use in the control of water hyacinth in an aquatic environment.View full abstractDownload PDF (702K) -
Tutomu KUWABARA, Yoshihisa ISHII, Yutaka NOMA1989 Volume 34 Issue 2 Pages 123-130
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSWe applied Paraquat herbicide to the same experimental fields (raising seedling fields of vegetable at the experimental farm of Faculty of Horticulture, Chiba University) three times a year for twenty years (1965-1984) consecutively (adding a mixture of herbicide 2, 4-D and Amitrole for the first seven years), and the effect of the herbicide application on the kinds and volume of weeds, that vegetated in the fields, was investigated (Tables 1, 2 and 5).
1. In the fields where weeding was practiced by man, no significant change was observed in the species composition and volume of weeds during the period of study (Table 3).
2. In the herbicide-treated fields, on the other hand, perennial and annual winter weeds disappeared after the continuous herbicide application for the twenty year period (Table 4).
3. The unique pattern of disapperance shown by each kind of weed was investigated. For perennial weeds, we assume the pattern might have been induced by such factors as the characteristics of the herbicide used and substantial time needed for the weeds to regenerate their plant body. For annual winter weeds, the pattern might be attributed to their specific vegetative period of winter.
4. As for annual summer weeds, the volume of vegetation was reduced to the 15% level of the initial value and remained unchanged for the rest of the period (Table 4).View full abstractDownload PDF (1029K) -
Masaru OGASAWARA, Makoto KONNAI, Tetsuo TAKEMATSU, Shozo KATO, Masahik ...1989 Volume 34 Issue 2 Pages 131-137
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn order to identify a new effective rice herbicide, α-chloroacetanilide derivatives were synthesized and their herbicidal activity and safety to rice were examined in a pot test carried out in a green house. The results are summarized as follows:
1. Pre-emergence treatment
The effects of the compound substituted on the amide nitrogen atom (Y) on the pre-emergence herbicidal activity against Echinochloa oryzicola VASING. and rice phytotoxicity were studied and the 2-thienylmethyl group was found to be most suitable (Table 2). The introduction of a methoxyl, methyl or chloro group at the 3 position on the thiophene ring further enhanced the activity (Table 3). The compounds used for substitution of the aniline moiety (X) greatly affected the activity and high activities were associated with the 2, 6-disubstituted compounds (Tables 4 and 5).
2. Post-emergence treatment
Post-emergence herbicidal activities against Echinochloa oryzicola VASING., Cyperus difformis L., Monochoria vaginaris L. and Rotala indica (WILLD.) KOEHNE for the selected compounds which had shown strong pre-emergence herbicidal activities were evaluated. Among them, α-chloro-N-(3-methoxy-2-thienyl) methyl-2′, 6′-dimethyl acetanilide (code number, NSK-850) which showed the highest activity, effectively controlled all the paddy weeds tested at a dose of 2.5g a. i./a and was active at lower doses than those of butachlor and pretilachlor against Echinochloa oryzicola VASING. (Table 6).View full abstractDownload PDF (785K) -
Masaru OGASAWARA, Makoto KONNAI, Tetsuo TAKEMATSU, Shozo KATO, Masahik ...1989 Volume 34 Issue 2 Pages 138-145
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSNSK-850, α-chloro-N-(3-methoxy-2-thienyl) methyl-2′, 6′-dimethylacetanilide, was studied for its herbicidal activity, selectivity and behavior in soil, including residual activity and mobility. The results are summarized as follows:
1. In a pot test carried out in a green house, NSK-850 effectively controlled Echinochloa oryzicola VASING., Cyperus difformis L., Rotala indica (WILLD.) KOEHNE, Scirpus juncoides ROXB. subsp. juncoides ROXB. and Cyperus serotinus ROTTB. at a dose of 1g a. i./a by pre-emergence treatment. The herbicide inhibited the growth of directly sown rice plants at a dose of 0.125g a. i./a, while transplanted rice plants were not affected even at a dose of 2g a. i./a (Table 4). NSK-850 showed a stronger herbicidal activity than pretilachlor against Echinochloa oryzicola at the 2-and 3-leaf stages, when the two herbicides were applied at doses at which they exhibited almost equal activities against the weed at the 1-leaf stage (Fig. 1). Activities of the herbicides decreased with the decrease of the depth of flooding water (Fig. 2). Echinochloa oryzicola once treated with 2g a. i./a NSK-850 at the 2-leaf stage slightly recovered from the inhibition 27 days after treatment. However, in the case of pretilachlor, recovery from the inhibition was observed 17 days after the plants had been treated with the herbicide at a dose of 4g a. i./a (Fig. 3).
2. In a field test, NSK-850 effectively controlled Echinochloa oryzicola, from the pre-emergence to the 2-leaf stages, at a dose as low as 3g a. i./a without adverse effect on transplanted rice plants. However, the control of Scirpus juncoides or Cyperus serotinus was not adequate (Table 5).
3. NSK-850 applied to flooded soil remained active for 30 days at a low temperature (5°C), whereas it lost its activity rapidly under high temperature conditions (30°C) (Fig. 4). When NSK-850 and pretilachlor were applied at doses at which they exhibited almost equal activity against Echinochloa oryzicola, 1 and 2g a. i./g respectively, the latter herbicide showed a slightly longer residual activity than the former. NSK-850 was less mobile than pretilachlor in the soils tested. Relative mobility of NSK-850 in the soils decreased in the order of sandy loam soil>loam soil>clay loam soil (Table 6).View full abstractDownload PDF (938K) -
IV. Control with HerbicidesKazuo CHIBA, Makoto KONNAI1989 Volume 34 Issue 2 Pages 146-153
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSExperiments were carried out to evaluate the effect of chemical control on Scirpus planiculmis FR. SCHM.
The results obtained are as follows;
1. Bentazon which was applied as foliar treatment in S. planiculmis, was a highly effective herbicide and did not cause injury to rice plant (Tables 3 and 4).
2. Foliar treatment with bentazon was ineffective in primary shoots less than 10cm in height (Figure 2). The optimum application time of bentazon was 30-40 days after transplanting of rice plant and repeated application of bentazon was recommended in the case of high planting density.
3. The parent tuber could not sprout as it withered by foliar treatment with bentazon (Table 9).
4. Bensulfuron methyl was most effective without causing injury to rice plant in the case of soil-application (Tables 1 and 2).View full abstractDownload PDF (832K) -
IV. Time of Dormancy Breaking of Tubers in Paddy FieldsKazuyuki ITOH, Masuji MIYAHARA1989 Volume 34 Issue 2 Pages 154-162
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn order to determine the time when the dormancy of arrowhead tubers (Sagittaria trifolia L.) was broken in paddy fields in normal season cultivation, the studies were carried out by changing the sampling time as under dark and light-sprouting conditions. The degree of dormancy breaking was estimated from the sprouting percentage for the first ten days.
The results obtained were as follows;
1) The dormancy of tubers formed in well-drained paddy fields was less deep at a low temperature (2-5°C) during winter. However, the tubers were still partially dormant in the field even in the beginning of March.
2) As the temperature (5-17°C) rose in spring, the dormancy of the tubers located at the soil surface and exposed to light was completely broken until the middle of May, while dormancy breaking of the tubers within the soil was broken in the end of June.
3) The above results suggest that light required for the breaking of dormancy of arrowhead tubers, as observed in the seeds of other weed species.
4) The dormancy of tubers formed in ill-drained paddy fields and under submerged conditions was gradually broken at a low temperature in winter. However some tubers with deep dormancy did not awake until the middle of May.
5) The above results of experiments under natural conditions confirmed the experiments of storage treatments in which the period of storage, temperature and soil water conditions were modified by the use of incubators.View full abstractDownload PDF (1027K) -
Yasuo HANIOKA1989 Volume 34 Issue 2 Pages 163-168
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESS1. The biotypes of Youngia japonica (L.) DC., a weed with a strong resistance to paraquat were investigated in April 1986 in mulberry fields located in Saitama Prefecture.
2. Leaf discs of such resistant plants were punched and dipped in a solution of paraquat and the degree of discoloration of the leaf in relation to the concentration of paraquat was examined. While the discs of plants tolerant to paraquat turned brown within 48 hours at a 1ppm concentration, those of the resistant plants retained their green color even at concentration of 10ppm but in some areas they displayed a brown discoloration at a paraquat concentration of 100ppm. Such a reaction was similar to that of the Erigeron philadelphicus L. and Erigeron canadensis L. plants resistant to paraquat. In addition, although the plants were resistant to diquat, the degree of resistance was lower than that to paraquat.
3. In the main sericultural zone of Saitama Prefecture, in May 1986, the distribution of Youngia japonica (L.) DC. plants resistant to paraquat was studied in mulberry fields corresponding to 235 sites in 5 areas. Although there were differences among the areas, resistant plants were recorded in 34% of the sites where they had occurred.View full abstractDownload PDF (699K) -
Hiroshi MATSUMOTO, Toru TOMINAGA, Tadashi SUMIYOSHI, Masaji KOSHIOKA1989 Volume 34 Issue 2 Pages 169-177
Published: August 30, 1989
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (1242K)
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