[Differentiation of vegetation characteristics on slope micro-topography of fenced watershed in loess area of north Shaanxi Province, Northwest China].[Pubmed: 22720613]

Based on the investigation data of the vegetations in Hegou valley in Wuqi County of Shaanxi Province, this paper studied the vegetation characteristics on the five typical micro-topography categories including shallow gully, gully, collapse, platform, and scarp in the loess area of north Shaanxi, with the undisturbed slope as the control. There existed distinct differences in the species composition, quantitative characteristics, and species diversity of plant communities on the five typical micro-topography categories and the undisturbed slope. After twelve years of enclosure recovery, the study area formed herbaceous plant community, with Artemisia sacrorum and Artemisia giraldii as the dominant species. Among the main companion species, shrubs such as Prinsepia uniflora and Caragana korshinskii were found in scarp and gully, and hygrophyte Phragmites australis appeared in platform. The coverage, height, and biomass of the plant communities on most of the micro-topography categories, especially on the gully and collapse, were larger than those on the undisturbed slope. The Shannon index on the micro-topography categories and undisturbed slope was in the order of scarp > gully > shallow gully > undisturbed slope > platform > collapse.

Two new alkaloid galactosides from the kernel of Prinsepia uniflora.[Pubmed: 22640596]

Two new alkaloid galactosides have been isolated from the kernel of Prinsepia uniflora. Their structures were elucidated as 5-[(α-D-galactopyranosyloxy) methyl]-1H-pyrrole-2-carbaldehyde (1) and 6-[(α-D-galactopyranosyloxy) methyl]-3-pyridinol (2) by various spectroscopic means including HR-ESI-MS, IR, 1D and 2D NMR. The determined structures were characterized with a unit of galactose which is rarely seen in the previously isolated pyrrole and pyridinol compounds.

[Distribution of hydrocyanic Acid in cormophyta: 15.1 new observations on cyanogenesis in Rosaceae].[Pubmed: 17401853]

Prunasin was isolated from leaves and roots of Aruncus silvester (= A. dioicus), leaves of Gillenia trifoliata and seedlings of Kageneckia lanceolata (all Spiraeoideae). Chamaebatiaria millefolium (Spiraeoideae - Sorbarieae) was found to be cyanogenic; in this instance the cyanogenic constituent seems to be different from prunasin, however. Prunasin was isolated also from buds and very young shoots of Crataegus irrasa (Maloideac - Crataegeae). Very young leaves of Crataegus cuneata and C. pedicellata also contain prunasin-like glycosides. Adenostoma fasciculatum, A. sparsifolium, all taxa of Cercocarpus tested and Coleogyne ramosissima were shown to have more or less strongly cyanogenic leaves. Together with Kerria, Neviusia and Rhodotypos these genera deviate from true Rosoideae by being cyanogenic and by having the basic chromosome number 9 instead of 7. The cyanogenic compounds of these taxa seem not to be derived from phenylalanine. Prinsepia uniflora (Prunoideae) has cyanogenic young shoots which do not contain prunasin or a similar compound. Within the species Aruncus silvester, Sorbus aria and Sorbus aucuparia cyanogenesis of leaves was found to be a highly variable character. The taxonomic meaning of cyanophoric compounds in Rosaceae is discussed briefly.