Steroids from the underground parts of Trillium kamtschaticum. (1/14)

Two 18-norspirostanol glycosides and an 18-norspirostanol, which were new compounds as natural products, have been isolated from the underground parts of Trillium kamtschaticum PALL. along with eight known steroidal glycosides. Their chemical structures were determined on the basis of spectroscopic data.  (+info)

Ecology: linking species diversity and genetic diversity. (2/14)

Although there is a great deal of interest in the biological diversity of species and of genes, it is only recently that researchers have begun to investigate the processes that exert parallel influences on these different levels of diversity.  (+info)

Distribution of genetic diversity among disjunct populations of the rare forest understory herb, Trillium reliquum. (3/14)

We assessed genetic diversity and its distribution in the rare southeastern US forest understory species, Trillium reliquum. In all, 21 loci were polymorphic (PS=95.5%) and the mean number of alleles per polymorphic locus was 3.05. However, genetic diversity was relatively low (Hes=0.120) considering the level of polymorphism observed for this outcrossing species. A relatively high portion of the genetic diversity (29.7%) was distributed among populations. There was no relationship between population size and genetic diversity, and we did not detect significant inbreeding. These results are best explained by the apparent self-incompatibility of this species, its longevity and clonal reproduction. To address questions regarding the history of T. reliquum's rarity, we compared results for T. reliquum with that of its more common and partially sympatric congener, T. cuneatum. Despite shared life history traits and history of land use, we observed significant genetic differences between the two species. Although T. cuneatum contains slightly lower polymorphism (Ps=85%), we detected significantly higher genetic diversity (Hes=0.217); most of its genetic diversity is contained within its populations (GST=0.092). Our results suggest that not only is there little gene flow among extant T. reliquum populations, but that rarity and population isolation in this species is of ancient origins, rather than due to more recent anthropogenic fragmentation following European colonization. The Chattahoochee River was identified as a major barrier to gene exchange.  (+info)

Two new steroid glycosides and a new sesquiterpenoid glycoside from the underground parts of Trillium kamtschaticum. (4/14)

Two new steroid glycosides, named trikamsterosides A and B, and a new sesquiterpenoid glycoside named trikamsesuquiside A were isolated from the underground parts of Trillium kamtschaticum PALL. along with 18 known compounds comprising 12 steroids, one sesquiterpenoid glycoside, one phenylpropanoid, one flavonoid glycoside, and three phenylpropanoid sucrose esters. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence. Among them, one phenylpropanoid sucrose ester showed almost the same radical-scavenging effect on 1,1-diphenyl-2-picrylhydrazyl as that of alpha-tocopherol.  (+info)

An 18-norspirostanol saponin with inhibitory action against COX-2 production from the underground part of Trillium tschonoskii. (5/14)

A novel 18-norspirostanol saponin (1), along with Trillenoside A (2), was obtained from the underground parts of Trillium tschonoskii MAXIM., collected in Shennongjia Forest District, China. Based on the chemical and spectroscopic evidences, their structures were determined as shown in Fig. 1. 1 and 2 displayed marked inhibitory action towards COX-2 production in macrophagocytes of the mouse abdominal cavity stimulated by LPS at 10 microg/ml.  (+info)

Three new steroid glycosides from the underground parts of Trillium kamtschaticum. (6/14)

Three new steroid glycosides named trikamsterosides C, D and E were isolated from the underground parts of Trillium kamtschaticum PALL. (Liliaceae) along with two known 18-norspirostanol glycosides trillenosides A and B. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence.  (+info)

Fine-scale spatial genetic structure within continuous and fragmented populations of Trillium camschatcense. (7/14)

Spatial genetic structure (SGS) within populations was analyzed for the ling-lived understory perennial herb Trillium camschatcense using allozyme loci. We used Sp statistics to compare SGS between 2 life-history stages, juveniles (J) and reproductives (R), as well as between 2 populations, continuous and fragmented, with different habitat conditions. In the continuous population, significant SGS was detected in both stages but the extent was greatly reduced with the progress of the stage (J, Sp = 0.0475; R, Sp = 0.0053). We inferred that limited seed dispersal and subsequent random loss of individuals from the family patches are responsible for the J and R stage structures, respectively. The fragmented population differed in the patterns of SGS; significant structure was detected in the R stage, but not in the J stage (J, Sp = 0.0021; R, Sp = 0.0165) despite significant positive inbreeding coefficients (J, F(IS) = 0.251). The observed differences in the J-stage structures between populations may be explained by habitat fragmentation effects because reduced recruitment in the fragmented population prevents the development of maternal sibling cohort. Such comparative analysis between populations and life-history stages can be useful to understand the different underlying causes of SGS.  (+info)

Timing of canopy closure influences carbon translocation and seed production of an understorey herb, Trillium apetalon (Trilliaceae). (8/14)

BACKGROUND AND AIMS: The light availability on a temperate, deciduous-forest floor varies greatly, reflecting the seasonal leaf dynamics of the canopy trees. The growth and/or reproductive activity of understorey plants should be influenced by the length of the high-irradiance period from snowmelt to canopy closure. The aim of the present study was to clarify how spring-blooming species regulate the translocation of photosynthetic products to current reproduction and storage organs during a growing season in accordance with the changing light conditions. METHODS: Growth pattern, net photosynthetic rate, seed production, and shoot and flower production in the next year of Trillium apetalon were compared between natural and experimentally shaded conditions. Furthermore, translocation of current photosynthetic products within plants was assessed by a labelled carbon-chase experiment. KEY RESULTS: During the high-irradiance period, plants showed high photosynthetic ability, in which current products were initially used for shoot growth, then reserved in the rhizome. Carbon translocation to developing fruit occurred after canopy closure, but this was very small due to low photosynthetic rates under the darker conditions. The shading treatment in the early season advanced the time of carbon translocation to fruit, but reduced seed production in the current year and flower production of the next year. CONCLUSIONS: Carbon translocation to the storage organ had priority over seed production under high-irradiance conditions. A shortened bright period due to early canopy closure effectively restricts carbon assimilation, which greatly reduces subsequent reproductive output owing to low photosynthetic products for fruit development and small carbon storage for future reproduction. As populations of this species are maintained by seedling recruitment, acceleration of canopy closure timing may influence the maintenance and dynamics of populations.  (+info)

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