All issues
Volume 41 (1996 - 199･･･
- Issue 4 Pages 281-
- Issue 3 Pages 157-
- Issue 2 Pages 79-
- Issue 1 Pages 1-
- Issue SupplI Pages 2-
Volume 41, Issue 4
Displaying 1-14 of 14 articles from this issue
- |<
- <
- 1
- >
- >|
-
Shigeru Takayanagi1997 Volume 41 Issue 4 Pages 281-285
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (548K) -
Hirofumi Yamaguchi, Shinya Umemoto1997 Volume 41 Issue 4 Pages 286-294
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn order to clarify the multiple functions of cover plants on paddy-levees, components of the paddy levee were determined, and types of paddy levees in Japan were classified. A typical Japanese paddy levee, Kansai type, is composed of three parts (Fig. 1); mae-aze (shore), flat part, and grassland. Based on the presence or absence of these three parts, their shape and feature, and way of coating the paddy levee, a key for paddy-levee classification was presented. Japanese paddy levee consists of 8 types (Azenashi, Teaze, Kuronashi, Kansai, Kyushu A, Kyushu B, Hokuriku, and miscellaneous types), 2 subtypes (Kansai subtype, and Hokuriku subtype), and 1 intermediate type between Kansai and Hokuriku types (Figs. 2, 3). In the Kansai type, the most mature type, the levee is covered by a highly diverse flora; perennial and annual hemicryptophytes, while the coated part of the paddy levee tends to be covered by annual weeds. The paddy-levee plants are valuable as edible and medicinal plants, and can be used for the prevention of soil erosion, as livestock feed, for landscaping, and as aesthetic plants (Fig. 3). The paddy levee should be managed for its cultural significance as well as cost-benefit aspects.View full abstractDownload PDF (3302K) -
Fan Deng, Kenji Usui, Ie Sung Shim, Katsuichiro Kobayashi, Kozo Ishizu ...1997 Volume 41 Issue 4 Pages 295-301
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe effect of the application of pretilachlor alone and in combination with fenclorim on the glutathione content, glutathione S-transferase (GST) activity and GS-pretilachlor conjugate content in 2-leaf-stage rice and early watergrass seedings was investigated.
Reduced glutathione (GSH) and oxidized glutathione (GSSG) contents in rice were higher than in early watergrass. GSH content in rice which decreased after pretilachlor treatment, returnes to normal values of treatment with the combination of pretilachlor and fenclorim, although the changes were not appreciable in early watergrass (Table 2). GST(pret) activity using pretilachlor as substrate was higher in rice than in early watergrass. The GST(pret) activity reached higher levels in rice than in early watergrass after treatment with pretilachlor and/or fenclorim for 24 hours (Table 3). GS-pretilachlor content was higher in rice than in early watergrass when the plants were treated with pretilachlor alone and a combination of pretilachlor and fenclorim (Fig. 1, Fig. 2).
It is considered that the difference in the GST(pret) activity and its induction may be the primary factors determining the selectivity of pretilachlor between rice and early watergrass, and that fenclorim protects rice from herbicide injury by pretilachlor mainly by inducing GST(pret) activity which catalyzes the detoxification of the herbicide.View full abstractDownload PDF (803K) -
Tadashi Sumiyoshi1997 Volume 41 Issue 4 Pages 302-309
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSEffect of sowing date, drainage treatment of mother plant and time of maturity on primary dormancy of seeds of Scirpus juncoides Roxb. subsp. juncoides was investigated at Tohoku Natl. Agric. Exp. Stn., Omagari, Akita, Japan. The results were as follows;
1. Under paddy field conditions, primary dormancy of the seeds collected in the late season was deeper than that of the seeds collected in the early season (Fig. 1).
2. Under pot conditions, primary dormancy of the seeds collected in the late season was deeper than that of the seeds collected in the early season, regardless of the sowing date (Fig. 2 to 4).
3. Primary dormancy of the seeds produced by plants subjected to drainage treatment in the growing season tended to be deeper than that of the seeds from plants not subjected to drainage (Fig. 5 to 6).View full abstractDownload PDF (964K) -
Mitsumasa Satoh1997 Volume 41 Issue 4 Pages 310-314
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe effect of acid rain on the photosynthesis, respiration, stomatal conductance and chlorophyll content of leaves in 10 species including weeds and crops was investigated after spraying of simulated acid rain at pH 2.5-3.5, 6 or 8 times in 2 weeks.
Plant species tested were divided into 3 groups according to their photosynthetic response to simulated acid rain. Photosynthetic activity in radish and kidney bean leaves decreased significantly after spraying of acid rain at a pH value below 3.0. In the case of Philadelphia fleabane and white clover leaves, the activity decreased after spraying of acid rain at pH 2.5, while it did not show any significant decrease in Polygonum lapathifolium, common lambsquarters, southern crabgrass, buckwheat, rice and tall fescue leaves. Respiration of the leaves increased in all the species after spraying of acid rain at pH 2.5. Stomatal conductance did not vary appreciably. Chlorophyll content of the leaves sprayed with acid rain decreased in the species tested except for southern crabgrass and tall fescue. A positive correlation was observed between the relative chlorophyll content, that is, the ratio of the chlorophyll a content of the treated leaves to that of the control leaves, and the relative photosynthetic rate which was calculated as mentioned above.View full abstractDownload PDF (589K) -
Osamu Watanabe, Takashi Enomoto, Katsuhisa Nishi, Toshiko Matano, Tohr ...1997 Volume 41 Issue 4 Pages 315-322
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSeasonal change in germination of P. crassinervis was compared to that of P. annua collected from the same habitat. Germination tests were made at 10, 15, 20, 25 and 30°C. To analyze the three phases of the germination process: the final cumulative germination percentage, the weighted mean germination ratio and the onset of germination, the cumulative seed germination curve was fitted to Richards' function model. P. crassinervis seeds germinated from late summer to early winter, while P. annua germinated throughout the year at 10°C. In both species, high cumulative germination percentage was found from August to December except for P. crassinervis seeds at 30°C. Cumulative germination curves of both species were very well fitted to Richards' function model. The time to reach maximum germination percentage in P. crassinervis was always shorter than that of P. annua when seeds were incubated at 10, 15, 20 and 25°C. An apparent seasonal dormant and non-dormant cycle and immediate germination were found in P. crassinervis. The germination characteristics of P. crassinervis seemed to be disadvantageous for seedling establishment in a severely disturbed habitat.View full abstractDownload PDF (884K) -
Amzad Hossain, Yukio Ishimine, Hikaru Akamine, Seiichi Murayama1997 Volume 41 Issue 4 Pages 323-331
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSTorpedograss (Panicum repens L.) is one of the most problematic rhizomatous weeds in tropical and subtropical regions. It was investigated to understand details of its growth and development characteristics to develop an effective and mechanistic simulation model of control measures. Sixty three plots of reddish soil (pH 5.25-6.74, soil hardness 3-4kg/cm2) 3m×3m in size were planted with single nodded rhizome cuttings. Nine samplings were made and each time five plots were randomly harvested. Aboveground shoot, rhizome elongation as well as tiller and rhizome production were slow during 30-50 days after planting (DAP). Rhizome began to develop from 50 DAP and continued up to the last harvest. Rhizome branching initiated after 50 DAP. Growth and development of rhizome was always faster than that of aboveground shoot. About 750g/m2 dry weight of rhizomes and roots showed a loose mat-like structure into soil up to 50cm deep. One emerged rhizome bud produced about 22, 635 rhizome nodes and 1, 628 bulbs by 365 DAP. Total biomass production was increased with days after planting though temperature was decreased. Three growth phases were identified: establishment phase (up to 70 DAP), moderate growth phase (70-110 DAP) and fast growth phase (110 DAP to the last harvest).View full abstractDownload PDF (2304K) -
Yuichiro Nakayama, Shinya Umemoto, Misako Ito, Tokuichi Kusanagi1997 Volume 41 Issue 4 Pages 332-338
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSA cultivation experiment was conducted on Plantago asiatica L. s. l. collected from eight natural populations in Kyoto City in order to detect intraspecific variation.
Among the populations, there was a remarkable genetic variation in the morphological traits of the plants, and two intraspecific types, common and minima types, were distinguished (Fig. 2) as follows: common type: leaves larger, plagiotropic; veins 5; inflorescence longer, plagiotropic or erect; seeds larger, 3-7 per capsule; minima type: leaves smaller, decumbent; veins 3; inflorescence shorter, ascendent; seeds smaller, 4-10 per capsule.
Based on the results of ANOVA for the quantitative traits of the plants, it was considered that some environmental factors of their habitats were closely related to the genetic variation of these two types (Table 2).
Ecological distribution of these two types was investigated at 168 locations in Japan, and some environmental factors of the habitats were also defined for 11 populations in Kyoto City to examine their contribution to the ecological distribution.
The common type was found on levees, paths between fields, roads, parking lots, shrine forest floors and so on, while the minima type was found only on the grounds of Shinto shrines and temples. The habitat of the minima type was characterized by relatively nutrient-poor soil, poor light conditions, low species diversity index and daily sweeping of the ground, which was remarkably different from those of the common type (Table 3), resulting in differences in the kind and intensity of stress and disturbance. The two intraspecific types of P. asiatica seem to have undergone a process of microevolution and maintained their habitat segregation as an adaptation mechanism to such different environmental conditions of their habitats.View full abstractDownload PDF (941K) -
Naoki Nakamura, Katsuichiro Kobayashi, Ie Sung Shim, Shizuo Nagatsuka1997 Volume 41 Issue 4 Pages 339-343
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe influence of organic matter content on adsorption of mefenacet [2-(benzothiazol-2-yloxy)-N-methylacetanilide] to soil and the phytotoxic activity was studied in relation to the concentration in water of soil with varying organic matter content. Soil samples were prepared with different organic carbon content by mixing the original soil (Yawara paddy soil) with soil oxidized by hydrogen peroxide. The phytotoxic activity of mefenacet applied to the soils containing various amounts of organic matter decreased as the organic carbon content increased, and was correlated well with mefenacet concentration in soil water. Mefenacet adsorption on solid phase decreased with decrease in organic carbon. Its adsorption on organic matter was similar to that of the soils tested, except for the oxidized soil. These results suggested that phytotoxic activity of mefenacet applied to the soil is substantially induced by the herbicide concentration in the soil water which is dominated by its adsorption on organic matter.View full abstractDownload PDF (546K) -
Ryuichi Sago, Katsuhiro Ushida, Teruo Matsuda1997 Volume 41 Issue 4 Pages 344-349
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSStudies were carried out to analyse the conditions for germination and the susceptibility of 9 herbicides in marsh dayflower (Murdannia keisak (Hassk.) Hand. -Mazz.). Seeds of marsh dayflower were collected at the Experimental Farm, Faculty of Agriculture, Ibaraki University in Ibaraki.
The mature seeds stored under dry conditions were distinct in their innate dormancy. The dormant seeds of marsh dayflower mostly germinated at alternating temperatures of 30/20°C, both under light and dark conditions when stored in water for 20 days at 5°C or soaked in concentrated sulfuric acid for one minute (Fig. 1, Table 2, Fig. 2). It took 6 days to obtain 50 percent germination at 10°C under dark conditions in dormancy-awakened seeds (Fig. 3). The emergence outdoors began at 8°C (mean air temperature). Buried seeds in submerged soil showed low emergence percentages and they become dormant after a short perioid of time (Fig. 4, Fig. 5.). The seeds in upland soil emerged from March to May and their emergence percentage was higher than that of seeds in submerged soil.
These results indicate that marsh dayflower is likely to emerge in paddy fields before transplanting of rice plant and that marsh dayflower may become a harmful weed in notillage or direct-seeding rice cultivation.
Marsh dayflower was easily controlled by chloroacetamides (mefenacet, pretilachlor) and carbamothioates (molinate) at the 2-3 leaf stage and the cutting of 5cm length (Table 3). Combination of bentazon and MCP inhibited the growth of marsh dayflower at the stage when the plant height had reached 28cm (Table 4).View full abstractDownload PDF (706K) -
Do-Jin Lee, Yasuhiro Yogo, Katsuichiro Kobayashi, Hirosi Sugiyama1997 Volume 41 Issue 4 Pages 350-355
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe relationship between soil moisture and concentration of soil-applied thiobencarb [S-(4-chlorobenzyl) diethyl thiocarbamate] in soil solution was investigated. When thiobencarb was applied to soil (low-humic andosols) at the same dosages based on air-dried weight, its concentration in soil solution was similar at any soil moisture level tested (45-75%, moisture weight percentage). Thus, the total amount of thiobencarb in soil solution increased as soil moisture increased regardless of the dosage applied. It was found that the partition coefficient of thiobencarb was inversely proportional to the application dosage at a given soil moisture condition in the soil. Bioassay with soil solution which was extracted by centrifugation with a double tube under various soil moisture conditions (45-75%) showed little difference in shoot growth of Echinochloa crus-galli (L.) Beauv. var. praticola Ohwi and Digitaria ciliaris Koeler. The rate of growth inhibition was almost identical with that of the freshly prepared thiobencarb solution. This supports that the concentration in soil solution is closely related to the herbicidal activity of soil-applied thiobencarb, although most of the thiobencarb was contained in the soil phase. Therefore, it was concluded that thiobencarb concentration in soil solution was almost constant under different soil moisture conditions.View full abstractDownload PDF (663K) -
Hitoshi Kuramochi, Guo Jun Qu, Makoto Konnai1997 Volume 41 Issue 4 Pages 356-358
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (300K) -
Naoki Nakamura, Masayuki Nemoto1997 Volume 41 Issue 4 Pages 359-361
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (372K) -
Akihide Fushimi, Hiroshi Tsuyuzaki, Yasuhiro Yogo, Akira Koarai1997 Volume 41 Issue 4 Pages 362-367
Published: January 31, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (850K)
- |<
- <
- 1
- >
- >|