巻号一覧
83 巻, 987-988 号
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Yasumasa SAWAMURA1970 年 83 巻 987-988 号 p. 299-303
発行日: 1970年
公開日: 2006/10/31
ジャーナル フリーPolygonum conspicuum, a perennial knotweed, is a sensitive short-day plant. It develops several long, branched rhizomes in a year. Effects of the photoperiod on the growth of rhizomes were investigated with this plant. Young plants grown from the cuttings were placed under 121/2-, 131/2-, 141/2, and 24-hour photoperiods and under the natural conditions from May to October, 1968. Observations made at intervals of a month showed that the total length and the branching of rhizomes were much increased under 121/2-hour photoperiods as compared with those under other longer photoperiods. Seven cycles of 8-hour photoperiods given in June or July also caused the promoted branching of rhizomes.
Under natural conditions, the branching of rhizomes was much promoted from September to October. This may be due to the shorter daylength during these months (12-111/2 hours). The ecological significance of the promotion of rhizome branching by short days is discussed.抄録全体を表示PDF形式でダウンロード (1147K) -
Makoto KIMURA1970 年 83 巻 987-988 号 p. 304-311
発行日: 1970年
公開日: 2006/10/31
ジャーナル フリーThe economy of dry matter was analysed in relation to the growth and matter production of Pteridophyllum racemosum, an evergreen perennial herb of Papaveraceae grown in the subalpine coniferous forest (2, 250m in altitude) of northern Yatsugatake Mountains, central Japan.
Annual respiratory loss of dry matter estimated from the seasonal change in respiratory activity of each orgen was 135g/m2 and corresponded to about 77% of the gross production, which was accounted to be 176g/m2•year as the sum totalof the net production and the respiration. Daily gross production was highest in early growing season. Measurements of the seasonal changes in the photosynthetic activity and the biomass of leaves of each age led to the conclusion that one-year-old leaves played an important role in matter production of the population in this season.
Two main phases were recognized in the annual matter economy of the plant. In the first phase, till the end of June, above ground new organs grew rapidly partly at the expense of the carbohydrate reserved in the old organs. In the second phase, from July to late November, reserves exhausted were refilled to be utilized in the next year. This phase was further divided into three sub-phases according to the behavior of the reserves and growth of roots. For each phase or sub-phase, the balance sheet of matter economy of the plant was constructed.
Based on these results, the characteristics in the annual matter economy of this plant were discussed in comparison with those of the plants of other perennial life forms.抄録全体を表示PDF形式でダウンロード (899K) -
Yutaka MURAKAMI1970 年 83 巻 987-988 号 p. 312-324
発行日: 1970年
公開日: 2006/10/31
ジャーナル フリーA survey of gibberellins in shoots (stem and leaves) from 86 species belonging to 82 families of moncotyledons and dicotyledons has been made. The extracts, fractionated by ethyl acetate, were purified by thin-layer chromatography and the eluates were applied to seedlings of the Tan-ginbozu and Waito-C dwarf varieties of rice by the microdrop method. With the Tan-ginbozu dwarf assay, zones having gibberellin activities were detected in the chromatograms of the extracts from 75 species. But Waito-C dwarf seedlings were almost insensitive to the same eluates except that from Phytolacca americana . From the specificity of the two dwarfs in response to gibberellins with different structures, it seems to be possible that gibberellins which have no β-hydroxyl group at the C-2 position in the A ring of gibbane might be widely distributed in shoots of monocotyledons and dicotyledons. Aspidistra elatior and Aucuba japonica had considerably higher concentrations of such gibberellins, and their contents were equivalent to 584 and 797mμg gibberellin A3 per 100g fresh weight of shoots, respectively.抄録全体を表示PDF形式でダウンロード (984K) -
S. NAKAZAWA, M. ABE, Margaret J. CALDWELL1970 年 83 巻 987-988 号 p. 325-329
発行日: 1970年
公開日: 2006/10/31
ジャーナル フリーEggs of Fucus evanescens were cultured on the surface of agar plate containing RNase at various concentrations from 0 to 50mg/100ml, in a dark box at 22° ± 2°. Rhizoid formation directly into the agar was almost completely suppressed at the higher concentrations of RNase, most of the rhizoids which did appear projecting sideways in a direction parallel to the agar surface. The proportion of decaying eggs also increased with elevation of the RNase concentration. These findings represent a type of polarity determination previously unreported in fucoid eggs; it seems valid to infer from them that intracellular localization of cytoplasmic RNA takes part in the actual formation of the rhizoid in situ .抄録全体を表示PDF形式でダウンロード (499K) -
Isao IKUSIMA1970 年 83 巻 987-988 号 p. 330-341
発行日: 1970年
公開日: 2006/10/31
ジャーナル フリーAn attempt was made to describe the distribution of light intensity at different depths in submerged plant communities quantitatively, in terms of the light extinction coefficients of both water and plants.
The rate of gross photosynthesis in floating leaves under high light intensities became saturated usually at the range of air-flow rate greater than 1.5 litre/cm2 leaf area/hr. The observed rates of gross photosynthesis at light saturation and respiration were 15-32mg CO2/dm2/hr and 1.1-3.5mg CO2/dm2/hr at 25°-27° and 300 ppm CO2.
The rates of daily gross photosynthesis in submerged and floating plant communities were estimated based on the mathematical model in which the effects of daily and depth-dependent changes of light intensity and the profile structure of plant communities were taken into consideration.
The rate of daily gross photosynthesis in Elodea Nuttallii communities in summer was nearly proportional to the shoot biomass where the latter was less than 300g/m2, and reached a maximum of about 25g dry matter/m2 land area/ day where the shoot biomass was more than 500g/m2. The total leaf area index in floating plant communities usually ranged between 1m2/m2 and 2m2/m2, and the net photosynthesis became negative in the third layer of leaves. The rates of daily gross photosynthesis and daily net production in a Nymphoides indica community with a leaf area index of 1.8 m 2/m 2 were 26.8 g dry matter/m 2 water surface/day and 15.2g/m2/day on a clear day in June.抄録全体を表示PDF形式でダウンロード (1157K)
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