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Volume 43 (1998)
- Issue 4 Pages 291-
- Issue 3 Pages 175-
- Issue 2 Pages 81-
- Issue 1 Pages 1-
- Issue Suppl Pages 2-
Volume 43, Issue 1
Displaying 1-9 of 9 articles from this issue
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Makoto Kitou, Shigekata Yoshida1998 Volume 43 Issue 1 Pages 1-9
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe objective of this investigation was to clearly the changes in the allelopathic effects of water extracts of soil amended with powdered plant materials (shoots of Artemisia princeps, Miscanthus sinensis, Pueraria lobata, Glycine max and Zea mays, and leaves of Acacia morisima and Solidago altissima) on the germination and root elongation of lettuce.
1. The germination and radicle elongation of lettuce were inhibited by the extracts of soil amended with any of these plant materials in the early period of incubation, although the inhibitory effects disappeared with the duration of the incubation period (Fig. 2, Fig. 3). Besides, radicle elongation was even promoted after the disappearance of the inhibitory effect (Fig. 2, Fig. 3).
2. The allelopathic effects of the extract of soil amended with leaves of S. altissima on the germination and radicle elongation of lettuce were strongest and persisted throughout the incubation period in this experiment (Fig. 2, Fig. 3).
3. Changes in the allelopathic effects of the extracts of soil amended with the ethanol soluble fraction of black wattle and tall golden rod leaves were comparable to those of the extract of soil amended with the unfractionated leaves (Fig. 4).View full abstractDownload PDF (1044K) -
Amzad Hossain, Yukio Ishimine, Kiyoshi Taniguchi, Makoto Konnai, Hikar ...1998 Volume 43 Issue 1 Pages 10-19
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSTorpedograss (Panicum repens L.) is a serious rhizomatous perennial weed in sugarcane (Saccharum offacinarum L.) in Taiwan, Hawaii and Okinawa. Two experiments were conducted to investigate torpedo-grass control and sugarcane injury using 2, 3 and 4kg ai/ha of asulam (methyl sulfanilyl carbamate) based on the time of herbicide application in the early growth stage of sugarcane. The asulam formulations used were SL (soluble concentrate, 37%) and WG (water soluble granule, 80%). Each formulation was applied at 20 days after planting (DAP) in the first experiment, and at 40DAP in the other experiment. Asulam SL and WG at 2 to 4kg ai/ha gave 100% control of torpedograss when applied either at 20 or 40DAP. Asulam applied at 20 and 40DAP required about 28 and 35 days after treatment, respectively to control torpedograss completely. Higher growth, yield and yield parameters of sugarcane were obtained by the 20DAP application of both formulations at 2kg ai/ha than those at higher rates. The formulations at 4kg ai/ha applied at 20DAP had severe injury effects on growth, yield and yield parameters of sugarcane, while 2, 3 and 4kg ai/ha of the formulations applied at 40DAP caused no negative impact on sugarcane growth, yield or yield parameters. Yield of sugarcane was significantly increased by all examined rates of the two asulam formulations applied at 40DAP in comparison with those of untreated weedy crop cultivation. The results of these experiments suggest that both asulam formulations (SL and WG) at 2kg ai/ha would successfully control torpedograss in sugarcane by post emergence application within 20-40 days of planting.View full abstractDownload PDF (1092K) -
Osamu Watanabe, Tohru Tominaga, Toshiko Matano1998 Volume 43 Issue 1 Pages 20-25
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSBoth intra- and inter-specific competition between Poa crassinervis and P. annua were studied by planting a target plant of either species at the center of a pot and surrounding with neighbouring plants of the same or the other species at three levels of planting density. The magnitude of the competitive ability was evaluated by growth of the target plant with the reciprocal technique.
The target plants of P. crassinervis had larger total dry weight in mixed stands with neighbouring plants of P. annua at a plant density of three plants per pot, compared with its total dry weight in the pure stand. However, the target plants of P. annua did not show any difference in dry weight between the two stand types at any plant density. When reciprocals of the target plant dry weight were plotted against neighbouring plant densities, the pure stand regression line of P. crassinervis located a little above its mixed stand line, and the interspecific competition with P. annua appeared to be greater than the intraspecific. In P. annua, the two regression lines were mostly overlapping at all plant densities of the neighbouring plants.
The results of both total dry weight production of the target plants and the reciprocal analysis suggested that the magnitude of interspecif is competition between these two Poa species of the genus was very small. The magnitude of their interspecific competition appeared to allow the two species to live sympatrically in western Japan.View full abstractDownload PDF (627K) -
Masayuki Nemoto, Toshiyuki Ohtsuka1998 Volume 43 Issue 1 Pages 26-34
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe suppressive effect of short-growing plants, i. e. Mazus miquelii Makino, Ixeris debilis (Thunb.) A. Gray and Duchesnea indica (Andr.) Focke, which commonly growing in surroundings of crop fields, on weed colonization was investigated. To examine this effect, experimental plots were constructed using these short-growing species.
1) All the short-growing plants investigated displayed rosette-like appearance with a procumbent stem, but the structure of their leaf canopy varied. Throughout the growing period the mean plant height of I. debilis was highest, but that of the other two species was maintained as low as almost a half (Fig. 1, Table 1). All these species vigorously elongated their stems from the middle of April. Stem elongation rate of D. indica was largest (Fig. 2). M. miquelii population completely covered the soil surface and its aboveground biomass was largest (Table 1).
2) Weeds which invaded plots with short-growing plants and control plots were all eliminated down to August 9 (the final weeding). There was a negative correllation between the percentage of cover by fresh leaves of the test plants on July 23 when their shoots had fully spread, and the dry matter production of invading weeds on October 6 (Fig. 4). On October 6 the aboveground biomass of invading weeds in all the plots planted with short-growing plants was significantly lower than that of non-planted control plots, indicating the suppression of colonization of invading weeds by the test plants (Fig. 3).
3) Thirty nine weed species invaded the experimental site of which eighty percent consisted of annuals. Appearance of Digitaria ciliaris overwhelmed that of other species in all the plots (Table 2). The mean value of the diversity index (bit) in the D. indica plots was highest, while that in the M. miquelii plots was lowest (Table 2).View full abstractDownload PDF (945K) -
Akiko Nagao, Kenji Usui, Hiroshi Matsumoto1998 Volume 43 Issue 1 Pages 35-42
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe induction of GST (pretilachlor) activity by fenclorim in rice shoot (Oryza sativa L. cv. Nipponbare) was studied in comparison with that by pretilachlor. Fenclorim was able to enhance GST (pretilachlor) and catalase activities as much as pretilachlor. But SOD activity after fenclorim treatment was much lower, and effect of superoxide scavenger (tiron) on the induction of GST (pretilachlor) by fenclorim was less than the case by pretilachlor. Therefore, the involvement of active oxygen in the induction of GST (pretilachlor) activity by fenclorim was assumed to be less than that by pretilachlor. GSH contents decreased after fenclorim treatment, but the decrease was also less than that after pretilachlor treatment. When GSH was applied prior to pretilachlor or fenclorim treatment, the increase of GST (pretilachlor) activity by pretilachlor was largely inhibited, but the increase by fenclorim was not inhibited effectively. This suggests that the level of GSH does not strongly affect the induction of GST (pretilachlor) by fenclorim as much as pretilachlor. It was concluded that active oxygens were partially involved in the induction of GST (pretilachlor) activity by chemicals conjugated with GSH. Although the involvements of active oxygens in the induction varied, they were assumed to correlate with the decrease of GSH after treatments.View full abstractDownload PDF (814K) -
Tohru Tominaga, Miyuki Nitta1998 Volume 43 Issue 1 Pages 43-48
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSeed germination was investigated in four populations of Perilla (Perilla frutescens var. frutescens) collected in Nagano, Japan. One of the four grew as a weed in a plum orchard, and the other three were cultivated by different practices. Seeds obtained from the four populations were sown on May 21, 1993, and mature seeds were harvested from raised plants from October 1 to November 1 of that year. The seeds of each population were divided into two groups. One was stored at a constant 5°C, and the other was stored at an alternate temperature. The germination of one hundred seeds in each population of both groups kept at 25°C was recorded at intervals of one month with three replications. The germination of freshly harvested seeds was investigated with three replications.
The germination percentage of each population increased with longer storage and was higher in the seeds stored under an alternate temperature than those stored under a constant 5°C. Freshly harvested seeds and those stored for less than two months in weedy perilla (No. 25 population) did not germinate, whereas 14% of the freshly harvested seeds germinated in no. 11 population, which was assumed to be the most domesticated type. After two months of storage under an alternate temperature, 80% of the seeds of no. 11 population germinated. The other two populations showed an intermediate pattern of germination between the no. 11 and 25 populations. The differences in the seed germination pattern seemed to be due to the differences in the degree of domestication.View full abstractDownload PDF (602K) -
Kangetsu Hirase, Daisuke Kishi1998 Volume 43 Issue 1 Pages 49-53
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (571K) -
Shun Kawaguchi, Masaru Ogasawara, Yamamoto Takeuchi, Makoto Konnai1998 Volume 43 Issue 1 Pages 54-56
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (360K) -
Ie-sung Shim, Reiichi Miura, Etsuko Ishikawa, Masaaki Tachibana, Akira ...1998 Volume 43 Issue 1 Pages 57-65
Published: May 06, 1998
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (1102K)
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