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Volume 23 (1978)
- Issue 4 Pages 151-
- Issue 3 Pages 101-
- Issue 2 Pages 49-
- Issue 1 Pages 1-
- Issue Suppl Pages 1-
Volume 23, Issue 3
Displaying 1-9 of 9 articles from this issue
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Sadao SAKAMOTO1978 Volume 23 Issue 3 Pages 101-108
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
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IV. Yearly and Seasonal Changes of Cover Degrees of WeedsHidejiro SHIBAYAMA, Masuji MIYAHARA1978 Volume 23 Issue 3 Pages 109-115
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSYearly changes of cover degrees of aquatic weeds were investigated in 1974 to 1977. Waterhyacinth [Eichhornia crassipes (Mart.) Solms] changed it biggest during four years, and its percentage was the highest in 1975, and the lowest in 1977. These changes appeared to be affected with temperature condition in every winter. Hairly subspecies of knotgrass (Paspalum sp.) increased it gradually year by year and became the worst weed in the investigated creeks. The cover degree of parrotfeather (Myriophyllum brasiliense Camb.) changed little yearly, but it decreased strikingly in 1977 because of laborious hand weeding in many creeks. Several other weeds increased little by little although they were still unimportant.
Seasonal change of that of waterhyacinth was also biggest, as almost all plants died of cold temperature in every winter. However, submerged shoots of Paspalum spp. and parrotfeather were alive even in winter and, therefore, their cover degrees did not change so much seasonally. Several species as giant duckweed (Spirodela polyrhiza (L.) Schleid.) changed them a little by season.View full abstractDownload PDF (980K) -
1. Effect of Nutrients on the Growth and ReproductionYoko OKI, Misako ITO, Kunikazu UEKI1978 Volume 23 Issue 3 Pages 115-120
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe purpose of this fundamental experiments was to determine the effect of nutrients on the growth and reproduction of waterhyacinth. The results obtained were as follows:
1) Plants grown in each solution with N, P or Ca deficiency depressed the growth and reproduction. Chemical analysis revealed that phosphorus content of the aerial portions was low in all above mentioned treatments.
2) As the ammonium N levels was increased from 0 to 160ppm in culture solution, the growth of adult plant increased. While in young plant the maximum growth occured in the 40ppm ammonium N solution. Also they produced a greater number of new plants in the 40ppm and the growth of new plants was maximum in this treatment. These results indicated that the optimum growth differed from the optimum reproduction in the nitrogen requirements.
3) The effect of various levels of phosphorus and calcium on the growth and reproduction was investigated. Plants grew well in water with a phosphate level over than 20ppm. As the phosphate content of the water was increased from 0 to 40ppm, phosphorus content of the aerial portions increased. While in calcium oxide, the minimum threshold concentration that showed normal growth was 5ppm. Even when the content of the water was increased, calcium content of the plant was not increased except the treatment of 80ppm.View full abstractDownload PDF (817K) -
2. Effect of Nitrogen Sources on the Growth and ReproductionYoko OKI, Misako ITO, Kunikazu UEKI1978 Volume 23 Issue 3 Pages 120-125
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSAn experiment was designed to study the influence of the sources of nitrogen supplied on the growth. The sources of nitrogen were ammonium (NH4-N), nitrate (NO3-N) and the two (NH4-N+NO3-N).
1) Maximum growth of both NH4-N and NH4-N+NO3-N plants occured in neutral or slightly basic water, while the growth of NO3-N plants were greater in acidic water than those in neutral or slightly basic water.
2) The new plants grew well in the NO3-N at pH 5 and pH 6, but they reached maximum growth in the NH4-N+NO3-N at pH 7 and pH 8.
3) Measurements of the initial and final pH levels of the culture waters indicated that ammonium was absorbed more selectively than nitrate by the plants in the nutrient with NH4-N+NO3-N.
4) Both total nitrogen content and total phosphorus content of the NH4-N plants were higher than those of the plants in NO3-N, while the calcium content of NH4-N plants was low.View full abstractDownload PDF (777K) -
Nobumasa ICHIZEN, Kunikazu UEKI1978 Volume 23 Issue 3 Pages 125-128
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSome physiological differences at the young stage in both plants, rice and barnyardgrass, were investigated to clarify selective responsibility to herbicides.
1) The dry weight and rate of transpiration per plant during 1 to 4 leaf-stage were greater in rice than in barnyardgrass.
2) The water content of plant during 1 to 4 leaf-stage was greater in barnyardgrass than in rice.
3) There was no difference in the chlorophyll content of leaves between rice and barnyardgrass at 2 leaf-stage.
4) The number of stomata per unit leaf area, respiration rate and TTC reduction and osmotic pressure of excised roots, rate of respiration and photosynthesis of leaf slices were measured using rice and barnyardgrass at 2 leaf-stage. All data in these experiments were superior in rice compared with barnyardgrass.View full abstractDownload PDF (487K) -
The Relation between Susceptibility to Benthiocarb and Seed Weight in GrassesNobumasa ICHIZEN, Kunikazu UEKI1978 Volume 23 Issue 3 Pages 129-133
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThis experiment was carrid out to investigate the relation between susceptivility to benthiocarb and seed weight in 20 species of grasses. The results obtained are as follows.
1) The positive correlation between ED50 value for benthiocarb and seed weight in 20 species of grasses was observed. And a smaller seed line of barnyardgrass was more susceptible to benthiocarb than larger one.
2) When the endosperms of rice seeds were partly cut off, the excised seeds were more susceptible to benthiocarb than the unexcised seeds.
3) The positive high correlation between seed weight and maximum leaf stage of grasses which were possible to grow in dark condition without any additional nutrient was observed with 20 species of grasses.
4) When rice plants and barnyardgrasses were at 3-leaf stage and 1-leaf stage respectively, their seed weights were about 10% of the original weights. And the diference between rice plant and barnyardgrass in susceptibility to benthiocarb decreased in the following order: 2-leaf stage, 1-leaf stage, 3-leaf stage, coleoptile stage, and 4-leaf stage.
5) The correlation between ED50 value for benthiocarb and crude fat content in 10 species of grasses was not recognized.View full abstractDownload PDF (587K) -
Minoru TAKABAYASHI, Kanenori NAKAYAMA, Tomoo FURUYA, Isamu KOYAMA1978 Volume 23 Issue 3 Pages 134-135
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
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Tomosaburo YABUNO1978 Volume 23 Issue 3 Pages 136-138
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
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Kazuyuki ITOH, Minoru TAKABAYASHI, Katsuyoshi NOGUCHI1978 Volume 23 Issue 3 Pages 139-144
Published: October 25, 1978
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (1046K)
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