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Volume 32 (1987)
- Issue 4 Pages 239-
- Issue 3 Pages 157-
- Issue 2 Pages 73-
- Issue 1 Pages 1-
- Issue Suppl Pages 1-
Volume 32, Issue 4
Displaying 1-10 of 10 articles from this issue
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Yukihisa OSHIRO1987 Volume 32 Issue 4 Pages 239-242
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
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Nobufumi NOMURA1987 Volume 32 Issue 4 Pages 243-246
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
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II. Distribution Pattern of Orchardgrass and Broadleaf dock (Rumex obtusifolius L.) in Newly Established SwardMamoru NASHIKI, Norikazu HARASHIMA, Kenzi SATO1987 Volume 32 Issue 4 Pages 247-254
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSCompetition among orchardgrass and R. obtusifolius plants, and plant performance in an orchardgrass sward were investigated in 1983 from the viewpoint of the distribution pattern of the plants expressed by the number and distance from neighboring plants which are represented by the Iδ index and Voronoi polygons.
The results obtained were as follows;
1) Invasion of R. obtusifolius into the orchardgrass sward resulted in a contagious distribution (Table 1, Fig. 1) of clumps consisting of a mixture of orchardgrass and R. obtusifolius plants.
2) The number of neighboring plants was the largest for orchardgrass close to both R. obtusifolius and orchardgrass clumps, as compared with orchardgrass close to an orchardgrass clumps only and R. obtusifolius close to both orchardgrass and R. obtusifolius clumps (Table 2).
3) Mean distances separating an orchardgrass clump (close to both R. obtusifolius and orchardgrass) from an R. obtusifolius clump of and another clump of orchardgrass were 7.51cm, 7.03cm, respectively. On the other hand, the distance separating a clump of R. obtusifolius from another R. obtusifolius clump was 6.10cm, and that between orchardgrass clumps close to an orchardgrass clumps was only 5.08cm (Fig. 3). The differences in the combinations of these neighboring plant species resulted in the difference in the distance between target plant species, which may account for contagious distribution mentioned above.
4) Invasion of R. obtusifolius decreased the population density of orchardgrass plants very close to R. obtusifolius shortly after sward establishment, but also promoted orchardgrass intraspecific competition resulting in a profuse growth of R. obtusifoius in the orchardgrass sward.
5) These results illustrate an example of competition for biological space between herbage and weeds. Further studies should be carried out to validate these data.View full abstractDownload PDF (966K) -
Hideo HOSAKA, Hideo INABA, Atsushi SATOH, Tohru TANOUE1987 Volume 32 Issue 4 Pages 255-262
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe herbicidal action of sethoxydim, 2-[1-(ethoxyimino)-butyl]-5-[2-(ethylthio) propyl)-3-hydroxy-2-cyclohexen-1-one, on red fescue (Festuca rubra L.) and tall fescue (Festuca arundinacea SHREB.) was studied in hydroponic and callus culture. Red fescue as a tolerant plant and tall fescue as a susceptible plant responded quite differently to root treatment with sethoxydim. Uptake, translocation, and metabolism of 14C-sethoxydim root-applied to red fescue and tall fescue were examined to elucidate the selective herbicidal action of sethoxydim between the plants. The amount of absorbed and translocated radioactivity was rather greater in tolerant red fescue than in susceptible tall fescue. The two species yielded similar metabolites and exhibited a similar degradation pattern.
Callus culture derived from both fescue species also reacted differently as well as in the hydroponic study.
Tolerance to sethoxydim in red fescue appears to be related to some physiological differences at the site of action rather than to differential uptake, translocation, and/or metabolism in whole plants in hydroponic culture, in comparison to tall fescue.View full abstractDownload PDF (2410K) -
Yuji YAMASUE, Kunikazu UEKI1987 Volume 32 Issue 4 Pages 263-267
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSeed germination of Echinochloa oryzicola, a gramineous weed in flooded rice, was studied to obtain substantive evidence for the operation of alcohol fermentation by comparing the patterns of change in alcohol dehydrogenase and cytochrome c oxidase activities with those in shoot and root growth, and by determining the quantitative relationship between CO2 and ethanol production. Non-dormant seeds incubated in air at 30°C, in the light had initially high activity of alcohol dehydrogenase, but it rapidly decreased and the activity of cytochrome c oxidase started to increase when the radicle growth began. However, the seeds in nitrogen, which showed good growth of the coleoptile with no radicle protrusion, maintained high activity of the dehydrogenase and low activity of the oxidase. Non-dormant seeds both in air and nitrogen produced ethanol and CO2 at constant rates, and molar ratios of the production, ethanol/CO2, until radicle protrusion were nearly 0.8 in air and 1.0 in nitrogen. These results indicated that the seeds respired mainly through alcohol fermentation regardless of O2 tension of the surrounding atmosphere. Moreover, the seeds grew shoots even under the anaerobic condition, but with no radicle growth, as often observed at water flooded rice fields.View full abstractDownload PDF (555K) -
Seed Dormancy and Germination of Echinochloa oryzicola VASING.: Ethanol as a Dormancy-Breaking AgentYuji YAMASUE, Ryo HASEGAWA, Kunikazu UEKI1987 Volume 32 Issue 4 Pages 268-273
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDormancy-breaking efficacy on seeds of Echinochloa oryzicola VASING. was studied with ethanol, the end product of alcohol fermentation, which is endogenously produced in a large amount in non-dormant seeds prior to the redicle protrusion. Primary dormancy of the seeds was markedly broken when dehulled seeds (fruits) were imbibed in 5% (v/v) ethanol solution or exposed to 80% ethanol for 30min. Methanol also showed a dormancy-breaking efficacy, but required higher concentration, among the other alcohols and organic solvents.
No germination was observed when intact seeds (spikelets) were treated with ethanol, probably because of its insufficient penetration, and the intact seeds vacuum infiltrated in 5% ethanol solution showed relatively high germination percentage. No significant difference in rate and amount of water absorption was observed between ethanol-treated and nontreated seeds.View full abstractDownload PDF (644K) -
Yukio ISHIMINE, Misao NAKAMA, Sigeo MATSUMOTO1987 Volume 32 Issue 4 Pages 274-281
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe allelopathic potential of Paspalum urvillei STEUD., Bidens pilosa L. ver. radiata SCHERFF. and Stellaria aquatica Scop., the dominant weeds in sugarcane fields in the Ryukyu Islands was investigated. The interaction between these weeds and their effects on five crop species was determined.
1. The plant height, top dry weight and leaf number of kidney bean were significantly reduced by weeds (Fig. 1, Tables 1, 3). The exudates of Paspalum and Bidens significantly reduced the root dry weight in squash, while no significant inhibition was exhibited by the exudate of Stellaria (Table 2). The exudate of the living plant and extract of the dead plant of Bidens inhibited the plant height in all the crops (Fig. 2) and significantly reduced the top dry weight in radish and the root dry weight in tomato (Table 4). The leaf number was generally much less affected and even increased when the crops were watered with the dead plant extract (Table 4).
2. The plant height was reduced significantly in Paspalum and much less in Bidens (Fig. 1). The top and root dry weights were reduced significantly in Paspalum (Tables 1, 2). The exudate of the living plant and extract of the dead plants of Bidens inhibited the plant height in Bidens (Fig. 2) and significantly reduced the top and root dry weights (Table 4). The top and root extracts of Bidens greatly inhibited radish and tomato from germinating, while the seed extract had little effect (Table 5).
The results suggest that the three weed species of the present investigation contain substances inhibitory to crop and weed growth, which may contribute allelopathically to the stable dominance of these weeds in sugarcane fields in the Ryukyu Islands.View full abstractDownload PDF (865K) -
Takeshi YUYAMA, Robert C. ACKERSON, Shunji TAKEDA, Yoshihisa WATANABE1987 Volume 32 Issue 4 Pages 282-291
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSTime-course changes in the concentration of bensulfuron methyl in the water of simulated rice paddies revealed a rapid decline in the concentration of the compound within 4 days of application. The decrease in water concentration was related to paddy soil type. On soils having the highest capacity to bind bensulfuron methyl, water concentrations declined more rapidly compared with soils that did not bind the compound as readily. Isothermal soil adsorption studies indicated that soil organic matter, total cation exchange capacity and soil pH influenced the degree of binding. Soils exhibiting a high content of organic matter, high clay content and low pH bound bensulfuron methyl most readily. Freundlich constants (K) were calculated for seven different soils and the values ranged from 2.1 to 112. The impact of water management was also examined in relation to the herbicidal efficacy of bensulfuron methyl.View full abstractDownload PDF (1034K) -
Misako ITO, Yukihide IYAMA, Kunikazu UEKI1987 Volume 32 Issue 4 Pages 292-299
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSFloristic composition was studied from July to August in 27 stands of an orchard where weeds were uniformly managed by mowing but species, ages and training systems of trees were different among the stands (Fig. 1).
Interstand similarity was evaluated by the values of Euclidean distance,
Djk=√Σni=1(Xij-Xik)2
where j and k are the stands that are compared, i is the weed species under consideration and X is the score, frequency. Light intensity was found to significantly affect the interstand similarity, as illustrated in the constellation pattern shown in Fig. 2. Among the stands with weak shading the similarity was very high as compared with that among the stands with strong shading. The stands which belonged to the blocks of immature trees (2 to 4 years old), however, were markedly different although they were not shaded or exposed to limites shading. This phenomenon was mainly ascribed to the high dominance of perennial species specific to each stand (Fig. 3), presumably caused by the dispersal of vegetative-reproductive organs which was associated with the soil disturbance at the time when the trees were replanted.
The proportion of several species varied among the stands, depending on the light intensity gradient. As the light intensity increased, the coverage of Digitaria adscendens increased whereas that of Polygonum logisetum decreased (Fig. 3). Paspalum distichum appeared more frequently under lighter conditions, while Microstegium japonicum, Poa annua, Plantago asiatica and Oenanthe javanica were mainly found under darker conditions (Fig. 4).
Total coverage of C4 plants tended to increase with the increase of the light intensity and was largely affected by the amount of D. adscendens (Fig. 5). The effects on the number of C4 species were not as apparent as those on the coverage.View full abstractDownload PDF (815K) -
Hiroyoshi OMOKAWA, Keiko NAKATANI, Hiroaki WATANABE1987 Volume 32 Issue 4 Pages 303-307
Published: December 18, 1987
Released on J-STAGE: December 17, 2009
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