摘要:

The study of several populations of the rare Corsican speciesA. cylindraceumGasp, allows the description of its population structure. During its development,A. cylindraceumis heterophyllous: the limb shape varies according to the age and size of the plant and the order of occurrence of the leaf. In the small populations, often counting less than ten plants, individuals are self fertile. In larger populations, they are self sterile. Most of the populations ofA. cylindraceumare clonal, but conservation of this species just needs ecosystem preservation.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515819

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Thermal analysis had showed that the decomposition of the plants at about 300° was mainly dependent on the cellulose content in dry matter, on account of the flammable evolved gas responsible of forest fires. The estimation of the fire risk is mainly proportional to the cellulose present. For thePinus halepensisthis risk will be very important for the pine—cones (green, brown, black), important for the needles, branches, barks, buds, and less important for the soft pine—cones in formation.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515820

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The synusiae and phytocoenoses from the main cool ravines of the Orne river valley (Calvados and Orne, France) are described thanks to an integrated phytosociology approach. A geosynphytosociological analysis of the landscape is then performed. Finally, the author deals with the place of ash—sycamore forests of western France within the framework of new European conservation programs.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515821

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In order to facilitate the pharmacological use of the plant, we thus decided to study the oil extracted from the seeds ofPeganum harmala.The oil was extracted from the seeds using Sohxlet and the extract was analysed by gaz chromatography (G.C.) and thin layer chromatography (T.L.C.). The G.C. Chromatograph (spectrum) revealed that insatured fatty acids are the major constituants of the oil where linoleic acid predomine oleic acid whereas, minor amounts of saturated fatty acids such as palmitic acid and stearic acid were present. Analysis by T.L.C. and H.P.L.C, indicated thatPeganum harmalaoil is a rich source of the major alkaloids, especially harmaline, harmine, harmalol and harmol.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515822

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In southern Tunisia where mean annual rainfall is less than 200 mm, the flora is more and more subject to a high and continuous human pressure for at least the last century. This flora includes about 850 species among which about 47 are trees and shrubs (c. 5 %). These trees and shrubs are among the most threatened species of the southern Tunisian flora for several reasons, as excessive use for domestic purposes, and their poor natural and even artificial regeneration.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515823

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The effects of benzylaminopurine (BAP) on the polypeptide pattern of membranes fromCatharanthus roseuscells were investigated using two- dimensional gel electrophoresis. In order to characterize the membrane preparation microsomes, issued from cells grown in different hormonal conditions (+2,4-D, -2,4-D, BAP), microsomes were harvested at different times of cell culture and tested for their ATPases prior to 2-D PAGE analysis. Inhibitory studies revealed that the total ATPase activity within these membranes was slightly affected by sodium azide and nitrate (less than 5%) indicating that mitochondrial and tonoplat vesicles were little represented in the crude fractions. Membranes contained, however, ATPases that were totally dependent on magnesium and strongly inhibited by orthovanadate (90% inhibition). Analysis by 2-D PAGE of the protein composition of these membranes revealed that the overall pattern was conserved after cytokinin treatment. A few polypeptides appeared, however, to be regulated by BAP. Particularly, the accumulation of a polypeptide with an apparent molecular mass of 33 kDa (P33) was increased markedly after cytokinin treatment. This stimulation was slightly inhibited by 2,4-D, a known inhibitor of alkaloid accumulation. Time course studies indicated that the effect of cytokinin on the accumulation of polypeptide P33 starts within 24 hours of cytokinin treatment and persists for at least 96 hours.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515824

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A cytological study of 25 individuals from differentDroserapopulations shows that the chromosome number of the four taxa occurring in Québec confirms the results already published for these species and does not vary.Drosera rotundifoliaL.,D. intermediaHayne andD. linearisGoldie possess 2n = 20 chromosomes, whileD. anglicaHuds. has 2n = 40. Three different hybrids however were detected:D. rotundifoliaxD. linearis(2n = 20),D. linearisxD. anglica(2n = 30) andD. rotundifoliaxD. anglica(2n = 30). The occurrence of the latter hybrid, well known in Europe and Japan (D. xobovataMert. & Koch), is cytologically confirmed for the first time in eastern North America. The nameD.xlinglicaKusakabe ex Gauthier & Gervais is suggested for thelinearis- anglicahybrid, whileD.xwoodiiGauthier & Gervais is proposed for thelinearis- rotundifoliaprogeny. The existence of spontaneous crosses involving D.rotundifolia, D. anglicaandD. linearisis consistent with the hypothesis thatD. anglicais an amphiploid resulting from the chromosome doubling of the sterilelinearisxrotundifoliahybrid. The meiotic pairing configurations observed in alinearisxanglica(2n = 30) hybrid suggest however that the process must have taken place with a primitiveD. linearissomewhat different from the present species.D. linearisis a species with narrow ecological requirements whose northeastern American lineage with some isolated western populations alone subsist and need protection.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515825

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In order to ordinate some territories according to the abundance of their endemic taxa, their floristic richness (number of taxa per unit of area), originality (number of endemic taxa per unit of area), and endemicity (percent of endemic taxa) are studied. Some causes of the inequalities between the different territoiries are briefly discussed.

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515826

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515827

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1253-8078    

DOI:10.1080/12538078.1999.10515818

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor