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Volume 37 (1992)
- Issue 4 Pages 267-
- Issue 3 Pages 195-
- Issue 2 Pages 83-
- Issue 1 Pages 1-
- Issue SupplI Pages 2-
Volume 37, Issue 2
Displaying 1-15 of 15 articles from this issue
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Yuji Yamasue1992 Volume 37 Issue 2 Pages 83-91
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
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Nobumasa Ichizen1992 Volume 37 Issue 2 Pages 92-96
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
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Mamoru Nashiki1992 Volume 37 Issue 2 Pages 97-104
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
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Tatsuya Inamura1992 Volume 37 Issue 2 Pages 105-112
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe control of old tubers and the relationship between the control of aerial parts and formation of new tubers were analysed in field experiments in which herbicides were applied for a three year period to the water chestnut, Eleocharis kuroguwai Ohwi. The results are as follows;
1. The control index, which is the ratio of the product of the number of hills and length of the weed plant in the herbicide-treated plots against that in the untreated control plot, was correlated with the degree of control of the aerial parts (Table 3).
2. The number of new tubers decreased when the aerial parts of weed were controlled. The decreasing rates were statistically equivalent during the experimental years (Table 4).
3. The decreasing rate of the new tubers at the time of the control of the aerial parts was high at the 0-15cm depth, but very low at the 15-25cm depth of soil layers (Fig. 2).
4. By controlling the aerial parts of the weed, the average diameter of the new tubers in the soil layers at the 0-10cm depth became smaller, and the average specific gravity and average weight at the 0-25cm depth decreased (Fig. 3, 4, 5).
5. The old tubers consisted of newly-formed ones and of their which had survived in the preceding years. The decrease of the specific gravity of the old tubers was considered to be caused by the growth inhibition of the aerial parts (Table 5, Fig. 5, 6).View full abstractDownload PDF (852K) -
Tatsuya Inamura1992 Volume 37 Issue 2 Pages 113-120
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe relationship between the growth inhibition of aerial parts and the sprouting and survival rates of tubers of the water chestnut, Eleocharis kuroguwai Ohwi was studied during the application of herbicides for a three year period and the effectiveness of herbicidal control was evaluated on the basis of the number of new and old tubers. The results are as follows;
1. The rate of sprouting of the old tubers was 60 percent and 72 percent of them consisted of old tubers which had sprouted in this year after surviving in soil for more than two years. On the other hand, 40 percent of the old tubers did not exhibit out sprouting and 84 percent of them originated from new tubers produced in the preceding year (Table 4).
2. The sprouting rate of the new and old tubers of water chestnut decreased with the increase of the growth inhibition of the aerial parts (Fig. 2, 3). The decrease of the sprouting rate of the new tubers was considered to be caused by the decrease of the specific gravity of the new tubers. The decrease of the sprouting rate of the old tubers was considered to be caused by the growth inhibition of the aerial parts and reduction in the nutrient content of the tubers required for re-sprouting (Table 3).
3. In order to decrease the number of tubers in the last year of the three year application of herbicides, the control index, which is the ratio of the product of the hill number and length of the weed plants, should be less than 10% at the tuber formation stage in the second year and lower in the third year in the herbicide-treated plots (Fig. 4, 5).
4. The survival rate, which is the ratio of the number of surviving new and old tubers in the next year against the number of all tubers in this year, decreased with the increase of the growth inhibition of the aerial parts (Table 4).
5. The relationship between the growth inhibition of the aerial parts by the three year application of herbicides and the sprouting and survivor ship of the tubers of water chestnuts was ascribed to a feedback-loop phenomenon.View full abstractDownload PDF (841K) -
Yoshie S. Momonoki1992 Volume 37 Issue 2 Pages 121-128
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe relationship between seed germination of Monochoria vaginalis var. plantaginea and gas composition in soil, i. e. ethylene, CO2, O2 and their combination was studied. A high germination percentage was obtained in the presence of both ethylene and CO2 regardless of the storage conditions, but in the presence of absorbents for both ethylene and CO2 the germination percentage declined significantly (Fig. 2 and Table 1). In the presence of CO2 absorbent, the application of ethylene to seed increased the germination percentage, while the effect of exogenous CO2 with the absorbent of ethylene on seed germination was very little. However, the germination percentage was increased by exogenous CO2 if the concentration was sufficiently high (Table 1). The effect of ethylene on seed germination of Monochoria may more important than that of CO2, and the seed germination is considered to be increased by endogenous ethylene.
The seeds under 60% oxygen exhibited a significantly decreased germination percentage while under 0.2% oxygen they showed high germination. No seeds, even non-dormant seeds, germinated in a petri dish with a filter paper in the presence of 21% oxygen (Fig. 1). The results demonstrate that Monochoria seeds require very little oxygen for germination.View full abstractDownload PDF (2162K) -
Kazuo Chiba, Choji Kawashima1992 Volume 37 Issue 2 Pages 129-133
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThis investigation was carried out to obtain informations for the breaking of a dormancy, sprouting and emergence of tubers in sea club rush under natural paddy conditions.
1) Tubers showed a spontaneous dormancy which was broken by the exposure to low temperatures. Under natural conditions, the breaking of the dormancy began from the end of November, and was almost completed at the end of January. Alternating temperature conditions also affected the sprouting of tubers (Figs. 1 and 2).
2) Time of the first emergence of sea club rush fluctuated depending on the snow melting time. The emergence occurred earlier in the years when snow melted earlier. In addition, it was observed that the accumulated value of the daily mean airtemperature from the snow melting time to the beginning of emergence of this species increased (approximately 100°C) in a year when the snow melted earlier, but decreased (approximately 40°C) in a year when the snow melted later (Fig. 6).
3) The emergence of tubers was later in well-drained field than ill-drained field.View full abstractDownload PDF (487K) -
Kazuo Chiba, Choji Kawashima1992 Volume 37 Issue 2 Pages 134-139
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSEffect of farm practices on the emergence and longevity of tubers under various conditions were examined.
1) Tubers were almost evenly distributed over 15cm of the plow layer in soil after puddling and the extent of distribution spread downwards (Fig. 1)
2) The emergence continued over several years when the same tubers were placed every year on the plow layer of the soil in a paddy-field, while half numbers of the tubers emerged after twenty years when they were buried at a 30 to 40cm depth below the surface of the paddy field (Table 2 and Fig. 5).
3) Tubers of sea club rush showed a relatively high tolerance to low temperature and drought (Table 3 and Fig. 6).
4) The tillage and puddling practices were effective due to the destruction of the growing buds of sea club rush by burial (Table 1). On the other hand, when the tubers were transfered into the deeper part of the plow layer, they remained dormant for several years or their emergence continued for a long time. The emergence of the tubers of sea club rush was prolonged since the source of reproduction was maintained over several years.View full abstractDownload PDF (604K) -
Kazuo Chiba, Choji Kawashima1992 Volume 37 Issue 2 Pages 140-145
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe Germination characteristics of seeds, growth of seedlings in paddy-fields and controlling effect of some herbicides on seedlings of sea club rush were examined.
1) Germination of seeds were observed in paddy-fields (Table 1).
2) The seeds is covered with a hard seed coat, resulting in slow water absorption. However water absorption was enhanced by the cutting of the basal part of seed and digestion of the seed coat with sulfuric acid (Fig. 2).
3) The seed of sea club rush germinated under alternating temperatures in the light, and the germination was markedly promoted by the cutting of the basal part of the seed (Fig. 3).
4) Seeds which had been buried in paddy soil for two or three years exhibited a higher germination percentage than those buried for one year (Table 2).
5) The growth rate of the seedlings was significantly lower than that of the shoots which had emerged from the tubers (Table 3).
6) The emergence of seeds was effectively controlled with some herbicides (Table 4).View full abstractDownload PDF (1717K) -
Hai-Hang Li, Mimako Urashima, Midori Amano, Labunmi Lajide, Hiroyuki N ...1992 Volume 37 Issue 2 Pages 146-152
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSBarnyardgrass (Echinochloa crusgalli L. Beauv. var. crus-galli) is a very serious weed throughout the world. Its allelopathy through its root exudates was studied. The cultural solution of barnyardgrass showed strong inhibition on seedling growth of lettuce and mung bean. The acidic-neutral fraction extracted from this cultural solution of barnyardgrass strongly inhibited seed germination and seedling growth of lettuce at 500ppm concentration. The basic fraction inhibited the growth of etiolated lettuce seedlings, but did not inhibit its seed germination. p-Hydroxybenzaldehyde and p-hydroxybenzoic acid were identified by HPLC and 1H-NMR as the main allelochemicals in the cultural solution released by the root of barnyard grass. 3, 4-Dihydroxybenzoic, vanillic acids and another unidentified inhibitor were also isolated from the solution.View full abstractDownload PDF (2188K) -
Hiroshi Matsumoto, Kozo Ishizuka1992 Volume 37 Issue 2 Pages 153-158
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSEffect of tetrapyrrole biosynthesis inhibitors on herbicidal activity of oxyfluorfen [2-chloro-1(3-ethoxy-4-nitrophenoxy)-4-trifluoromethylbenzene] and protoporphyrin IX accumulation was determined in intact cucumber seedlings. Oxyfluorfen induced rapid light dependent bleaching and desiccation in the plant. The tetrapyrrole biosynthesis inhibitors, gabaculine and 4, 6-dioxoheptanic acid, strongly suppressed oxyfluorfen activity when the roots were treated with these chemicals for 15hr prior to the herbicide treatment to the shoots. A large accumulation of protoporphyrin IX occurred in oxyfluorfen-treated cotyledons in advance of the appearance of herbicidal symptoms. The inhibitors also reduced protoporphyrin IX accumulation and the pattern of reduction was very similar to that of herbicidal activity. These data indicate that protoporphyrin IX plays a critical role in the mode of action of oxyfluorfen in intact cucumber plants.View full abstractDownload PDF (603K) -
Masayuki Nemoto, Yuji Nagasaki, Masaharu Ikeda1992 Volume 37 Issue 2 Pages 159-166
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSRecently, the occurrence of degraded grasslands dominated by Paspalum conjugatum Berg., a tussock-prostrate type of perennial grass, has been increasing in Okinawa prefecture, Japan. P. conjugatum which grows well all the year round in this region is a harmful weed for domestic animals. For these reasons, integrated control of P. conjugatum must be carried out. However, the physiology, ecology and control of this weed remain poorly documented.
P. conjugatum did not make a pure stand in grasslands (Table 1), but it was able to easily invade gaps (Fig. 1, 5). The gaps were often formed in grasslands for the following reasons: 1) death of sown grass such as Chloris gayana Kunth. by drought, 2) removal of the soil surface by sliding of mower or tramping of animals. 3) plant materials remaining after mowing. P. conjugatum firstly elongated stolons and occupied the gaps and then formed dense colonies (Fig. 3). Once P. conjugatum invades the sown grasslands consisting of C. gayana or Panicum maximum Jacq., its habitat can be secured. However, in grasslands dominated by Cynodon plectostachyus (K. Schum.) Pilger. the growth of P. conjugatum was suppressed and appeared to be spindly (Fig. 2, 4). The plant height of C. plectostachyus was higher than that of P. conjugatum (Fig. 2). It is suggested that the introduction of a prostrate type of forage such as C. plectostachyus in grassland could be an effective measure for the control of P. conjugatum.View full abstractDownload PDF (751K) -
Mitsumasa Satoh, Youzou Usami, Hiroshi Koizumi, Hiroaki Ichikawa, Yanh ...1992 Volume 37 Issue 2 Pages 167-168
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
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Soichi Nakayama, Yoshiaki Kawana, Kiyoshi Matsuo, Yasuhiro Yogo1992 Volume 37 Issue 2 Pages 171-175
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
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Hiroaki Watanabe, Keiko Nakatani, Hiroshi Tsuyuzaki, Yasuhiro Yogo1992 Volume 37 Issue 2 Pages 176-180
Published: July 31, 1992
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (590K)
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