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101.
The only representatives ofRubiaceae-Rubieae in Madagascar are five species ofGalium. G. thunbergianum andG. chloroionanthum are essentially afromontane species, ± widely distributed in both the African mainland and Madagascar. The new speciesG. andringitrense andG. ankaratrense are endemic to Madagascar but show close affinities to two afromontane—afroalpine groups from the African mainland, theG. simense—G. ruwenzoriense andG. glaciale complex respectively.G. polyacanthum (new combination) exhibits certain primitive morphological traits and appears to be an old Madagascan endemic without close allies. New chromosome counts for populations from the African mainland demonstrate thatG. chloroionanthum andG. simense are 4x (x=11). Distribution patterns and origins of theGalium species in Madagascar and their relationships with African taxa are discussed. 相似文献
102.
103.
Elisabeth Tillberg Christian Dons May Haugstad Stein Nilsen 《Physiologia plantarum》1981,52(4):401-406
The effects of abscisic acid (ABA) on photosynthesis, dark respiration, and photorespiration were studied in Lemna gibba L. plants. The initial concentration of ABA in the nutrient solution was 10−7 M and in a few experiments, 10−6 M. The cultures were grown in the same solution for time periods ranging from one hour to 12 days. Net photosynthesis, measured as CO2 uptake by infrared gas analyser technique, was inhibited after four hours of ABA treatment and reached a minimum after four to seven days depending on the time of the year. After 12 days a substantial recovery of photosynthesis was observed. Dark respiration was significantly stimulated after two to seven days of ABA treatment but then returned to the control level. The transient effects of ABA on photosynthesis and dark respiration corresponded to the previously measured time course of [14 C]-ABA uptake by Lemna . Photorespiration measured as oxygen inhibition of photosynthesis was not affected by ABA. 相似文献
104.
Louis Piovetti Christian Francisco Ginette Pauly Otmane Benchabane Colette Bernard-Dagan Anne Diara 《Phytochemistry》1981,20(6):1299-1302
Analysis of wood essential oil of Cupressus dupreziana revealed 26 components: 13 monoterpenes and 13 sesquiterpenes. The main components were carv 相似文献
105.
Christian Gaillard 《Geobios》1980,13(3):465-471
A new trace fossil corresponding to a spiral burrow is described in the Upper Valanginian of the Ardèche area (France). It seems to be restricted to marine hemipelagic facies (outer shelf and upper slope). 相似文献
106.
107.
Christian Mouton Homer S. Reynolds Edward A. Gasiecki Robert J. Genco 《Current microbiology》1979,3(3):181-186
The adhesive interaction between the ectosymbionts of the corn cob configuration (CCC), a naturally occurring bacterial consortium
in human dental plaque, was studied. In vitro association was produced in mixed cultures consisting ofBacterionema matruchotii and streptococci resemblingStreptococcus sanguis previously isolated from human CCC. Phase-contrast, selective immunofluorescence, and scanning electron microscopy showed
that in this aggregative system, a tuftlike polar structure typical of the coccal epibiont mediated binding to the core filament.
This aggregative model provides evidence that a specialized structure on the cell surface of epiphytic organisms may participate
in interbacterial adherence. 相似文献
108.
New topics on ecology and systematics of recent and fossil Lingulids lead to an obvious revision of our knowledges on this zoological group. At first, the recent species need systematics and taxonomy on the bases of new described specific criteria (as, morphology of deltidial areas, muscle disposition); the results are briefly indicated. But, in fossil species, disorder and disparity of used characteristics are emphasized.The general conceiving on ecology of Lingulids are reviewed and discussed, especially on bathymetry and salinity; sediment and oxygenation conditions; taphocoenosis and lingulid «communities. On recent species, all these points are also studied, especially some ecological requirements (salinity, bathymetry, grain size), and mechanism of burrowing ability, burrow living positions in the sediments, as shell preservations after death and fossilization, to facilitate the paleobiotope interpretations. Recent animals are euryhalin, surviving at salinities from about 13 to 42‰; they could be considered as well adapted to waters with strong salinity fluctuations. They show preference to fine sand bottoms (lowest particle size about 40–60 μm). Their bathymetric distribution occurs between 0 and about 500 m (Lingula especially between 5–50 m; Glottidia 15–70 m). The isotherms 8–10°C seem to restrict their geographical and bathymetric distribution.Therefore, some post-palaeozoic lingulid bedsare studied or redescribed on the bases of the above discussed characteristics, and new interpretations on the environmental situation are given (Trias of Vosges Mountains; Oligocene from Japan; Eocene of London Basin). More caution must be used in study of fossil Lingulids that are not especially animals living in infralittoral bottoms with low salinity and deficient oxygenation, as generally accepted. 相似文献
109.
When Lemna minor L. is transferred to an atmosphere with H2S, there is a rapid loss of extractable adenosine-5-phosphosulfate sulfotransferase activity. The activity is restored within 24 h in an atmosphere without H2S. This restoration of activity is completely inhibited by cycloheximid but not by chloramphenicol. In vitro, S2- up to 5 mM and cysteine, methionine, and glutathione up to 50 mM do not inhibit the enzyme. The activities of ATP sulfurylase and O-acetyl-L-serine sulfhydrylase are not affected significantly by H2S. The physiological significance of the regulation of adenosine-5-phosphosulfate sulfotransferase is discussed.Abbreviations APS
adenosine-5-phosphosulfate
- PAPS
adenosine-3-phosphate-5-phosphosulfate
- BSA
bovine serum albumin
- DTT
dithiothreitol
- POPOP
1,4-di [2-(5-phenyloxazolyl)]-benzene
- PPO
2,5-diphenyloxazol
This is no. 6 in the series Regulation of Sulfate Assmilation in Plants 相似文献
110.