Population genetic differentiation of Schisandra chinensis and Schisandra sphenanthera as revealed by ISSR analysis

Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils. are well-known Chinese medicinal plants. The population genetic variation of the two species was studied using inter simple sequence repeat (ISSR) molecular markers. High levels of genetic diversity are revealed in both S. chinensis (P = 88.36%, h = 0.2894, I = 0.4396) and S. sphenanthera (P = 84.09%, H = 0.2782, I = 0.4280). However, the population genetic differentiation is significantly different between the two species. The S. sphenanthera harbors as high as 27% of the genetic variation among populations but 73% within populations, whereas in S. chinensis 17% of the genetic variation occurs among populations and 83% within populations. Both significant (P < 0.05) heterozygosity excess and shifted mode of allele frequency distribution are detected in four out of six populations of S. chinensis and one out of five populations of S. sphenanthera, suggesting the occurrence of recent population bottlenecks in the two species. The different patterns of genetic variation in S. chinensis and S. sphenanthera are discussed in relation to their differences in pollination mechanism, geographic distribution and historical events, and the level of gene flow and genetic drift.     

Phylogeny of Schisandraceae based on morphological data: evidence from modern plants and the fossil record

Schisandraceae are traditionally subdivided in two genera, Schisandra and Kadsura, based on differences in the organisation of the floral receptacle, the carpels, and the presence or absence of a ``pseudostigma'. Recently, phylogenetic analyses utilizing ITS sequence data and morphological data resulted in incongruent tree topologies, with the morphological trees suggesting monophyly of the two genera, whereas ITS trees did not resolve Schisandra and Kadsura as monophyletic clades. In the present paper we study seed morphology and leaf epidermal features of 22 species of Schisandraceae in order to provide additional data for a morphological data matrix. Seed morphological characters are highly homoplastic and do not yield further evidence for monophyly of the two genera. Instead, a number of characters appear to support sister group relationships between taxa within the genera, such as, for instance, for K. coccinea and K. scandens, both of which have large seeds along with a multi-layered mesotesta. Considering leaf epidermal characteristics, species of Kadsura were found to be consistently amphistomatic, whereas species of Schisandra are always hypostomatic. Phylogenetic analysis using the extended data matrix resulted in weakly supported Kadsura and Schisandra clades with five and four synapomorphies indicating monophyly of Kadsura and Schisandra, respectively. Fossils ascribed to Schisandraceae date back to the Late Cretaceous. These are tri-and hexacolpate pollen types displaying a combination of features found in modern Schisandraceae and partly also in Illiciaceae. Leaf remains from this period are poorly preserved and difficult to ascribe to Schisandraceae because of the lack of synapomorphies for the family. In the Early Cainozoic, leaf and seed remains from North America and Europe unambiguously belong to the family. Seeds from the Eocene of North America show some similarities to the modern Schisandra glabra from North America, while fossils from Europe show more similarities to modern Asian species.     

Chemical Constituents of Schisandra rubriflora Rehd.et Wils.

Schisandra rubriflora Rehd. et Wils. is a traditional Chinese medicine. To search for new and bioactive components from traditional Chinese medicines and provide scientific evidence for taxonomy, the chemical constituents ofthe plant were investigated by various column chromatography methods (silica gel,Sephadex LH-20, and RP-18). From the aerial parts ofS. rubriflora, three new megastigmane glycosides,namely (3S, 5R, 6S, 9R)-megastigmane-3, 9-diol 3-O-[α-L-arabionfuranosyl-(1→6)-β-D-glucopyranoside](1), 7-megastigmene-3-ol-9-one 3-O-[o-L-arabionfuranosyl-(1→6)-β-D-glucopyranoside] (2), and megastigmane-3α, 4β, 9ξ-triol 3-O-β-D-glucopyranoside (3), along with 14 known compounds, were isolated.The structures of the new compounds were elucidated by a combination of spectroscopic and chemical methods.     

五味子科植物的木脂素类成分及生物活性与国内资源

五味子料(Schisandraceae)是一类重要的药用植物.本文简述从国产的12种五味子植物中分离出近70个木脂素成分,并着重介绍木脂素成分降低谷丙转氨酶的研究结果以及其他主要活性。并对国内五味子科植物的分布和资源利用作了介绍.     

Pollination of Schisandra henryi (Schisandraceae) by female, pollen-eating Megommata species (Cecidomyiidae, Diptera) in south-central China

BACKGROUND AND AIMS: The mutualistic interaction between insects and flowers is considered to be a major factor in the early evolution of flowering plants. The Schisandraceae were, until now, the only family in the ANITA group lacking information on pollination biology in natural ecosystems. Thus, the objective of this research was to document the pollination biology and breeding system of Schisandra henryi. METHODS: Field observations were conducted in three populations of S. henryi and the floral phenology, floral characters and insect activities were recorded. Floral fragrances were sampled in the field and analysed using TCT-GC-MS. Floral thermogenesis was measured with a TR-71U Thermo Recorder. Pollen loads and location of pollen grains on insect bodies (including the gut) were checked with a scanning electron microscope and under a light microscope. KEY RESULTS: Schisandra henryi is strictly dioecious. Male flowers are similar to female flowers in colour, shape, and size, but more abundant than female flowers. The distance between tepals and the androecium or gynoecium is narrow. Neither male nor female flowers are fragrant or thermogenic. Schisandra henryi is pollinated only by adult female Megommata sp. (Cecidomyiidae, Diptera) that eat the pollen grains as extra nutrition for ovary maturation and ovipositing. Both male and female flowers attract the pollinators using similar visual cues and thus the female flowers use deceit as they offer no food. CONCLUSIONS: Schisandra henryi exhibits a specialized pollination system, which differs from the generalized pollination system documented in other ANITA members. Pollen is the sole food resource for Megommata sp. and the female flowers of S. henryi attract pollinators by deceit. This is the first report of predacious gall midges utilizing pollen grains as a food source. The lack of floral thermogenesis and floral odours further enforces the visual cues by reducing attractants for other potential pollinators.     

五味子科几个分类学问题探讨

基于近年来的研究成果,对五味子科的分类地位和系统关系、五味子属和南五味子属之间的关系及其分类系统等问题进行了讨论。五味子科和八角科不仅亲缘关系较近,而且是现存被子植物中最早分化出来的类群,把它们同置于八角目是合理的。五味子科的两个属——五味子属和南五味子属,可能源于同一祖先并沿两条不同演化路线平行演化。目前,关于南五味子属的分类系统的意见比较一致,但对五味子属分类系统的分歧却很大。     

Micromorphological features of the seed surface of Schisandraceae and their systematic significance

Micromorphological features of the seed surface of the Schisandraceae are reported for the first time. One hundred and seventeen seed samples from 92 populations, representing 24 species, seven varieties and one form of the Schisandraceae, were examined and photographed under scanning electron microscope (SEM). Micromorphological features of seed surfaces of the Schisandraceae are little affected by the habitats in which plants grow, and are quite constant within species, therefore they can be used as reliable diagnostic characters to distinguish species. The following taxonomic treatments are not supported by micromorphological features observed: ( 1 ) To reduce Schisandra wilsoniana A. C. Smith to S. henryi Clarke; (2) To reduce S. neglecta A. C. Smith, S. arisanensis Hayata, S. viridis A. C. Smith, S. sphenanthena Rehd. & Wils., S. gracilis A. C. Smith, S. micrantha A. C. Smith and S. lancifolia var. polycarpa Z. He to S. elongata ( Bl. ) Baill.; (3) To reduce S. henryi var. longipes (Merr. & Chun) A. C. Smith, S. tomentella A. C. Smith and S. pubescens var. pubinervis (Rehd. & Wils.)A. C. Smith to S. pubescens Hemsl. & Wils.; (4) To reduce S. rubriflora(Franch.)Rehd. & Wils., S. flaccidiramosa C. R. Sun, S. incarnata Stapf, S. sphaerandra Stapf, S. sphaerandra f. pallida A. C. Smith and S. glaucescens Diels to S. grandiflora ( Wall. ) Hook. f. & Thoms.; (5) To reduce Schisandra wilsoniana to S. bicolor Cheng; (6) To reduce S. lancifolia var. polycarpa to S. neglecta; (7) To raise S. henryi var. longipes to S. longipes(Merr. & Chun)R. M. K. Saunders; (8) To reduce Kadsura polysperma Yang to K. heteroclita(Roxb. )Craib. The relationship between Schisan-dra Michx. and Kadsura Kaempf. ex Juss. revealed by the micromorphological features of seed surface is very similar to that revealed by pollen morphology, namely these two genera might have originated from a common ancestor and then evolved along two different routes. However the probability of a more complicated relationship between the two genera than we have known hitherto can not be excluded. The general evolutionary level of Kadsura seems to be higher than that of Schisandra. Therefore, the viewpoint that Kadsura is more primitive than Schisandra is not supported.     

Pollen morphology of the Schisandraceae and its systematic significance

Pollen morphology of 91 samples, representing 23 species, 6 varieties and 1 form of the Schisandraceae, was examined under light microscope (LM) and scanning electron microscope (SEM). Palynological data of 5 species, 4 varieties and 1 form are reported for the first time. The pollen grains are monads, heteropolar, radiosymmetric and oblate to peroblate in shape. Arrangement of their colpi is unique in angiosperms. The pollen grains can be divided into two types according to the number of their clopi: the tricolpate pollen type and the hexacolpate pollen type. The exine sculpturing is reticulate. The size of luminae and the breadth of muri are correlated with the floral morphology of the hisandraceae to a certain extent. Our results do not support the division of the pollen grains of the Schisandraceae into 4 types according to the size of inae as proposed by Praglowski. There is also still room of discussion about his conclusion that the pole where the three longer colpi converge is the distal pole. The evolutionary trends of the pollen grains of the Schisandraceae seem to be from fewer to more in the number of colpi, and from smaller to larger in the size of luminae. The view that Kadsura is more primitive than Schisnadra is not supported by palynological data; on the contrary, Kadsura seems to be more advanced than Schisandra at the general level of evolution. The two genera may be closely related, and might have originated from a common ancestor and then evolved parallelly along two different routes.     

Chemical Constituents of Schisandra rubriflora Rehd. et Wils.

Schisandra rubriflora Rehd. et Wils. is a traditional Chinese medicine. To search for new and bioactive components from traditional Chinese medicines and provide scientific evidence for taxonomy, the chemical constituents of the plant were investigated by various column chromatography methods (silica gel, Sephadex LH-20, and RP-18). From the aerial parts of S. rubriflora, three new megastigmane glycosides,namely (3S, 5R, 6S, 9R)-megastigmane-3, 9-diol 3-O-[α-L-arabionfuranosyl-(1→6)-β-D-glucopyranoside](1), 7-megastigmene-3-ol-9-one 3-O-[α-L-arabionfuranosyl-(1→6)-β-D-glucopyranoside] (2), and megastigmane-3α, 4β, 9ξ-tfiol 3-O-β-D-glucopyranoside (3), along with 14 known compounds, were isolated.The structures of the new compounds were elucidated by a combination of spectroscopic and chemical methods.     

Nortriterpenoids and lignans from Schisandra sphenanthera

Nortriterpenoids, sphenadilactone C (1) and sphenasin A (2), together with four known lignans (3-6), were isolated from the leaves and stems of Schisandra sphenanthera. Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and compound 2 was further confirmed by single-crystal X-ray diffraction. Compound 1 features a partial enol moiety and an acetamide group in its structure. In addition, compounds 1, 3-6 showed weak anti-HIV-1 activity with EC₅₀ values in the range of 15.5-29.5 μg/mL.