凤凰蜘蛛抱蛋(铃兰科)的补充描述及核型

通过野外和标本室观察,发现凤凰蜘蛛抱蛋的原始描述存在一些错误。重新详细描述了该种的花部形态特征,补充了果实形态特征的描述,并首次报道了其染色体数目(2n=38)和核型(2n=22m+6sm+10st)。根据核型特征,认为该种的近缘种应为四川蜘蛛抱蛋和乐山蜘蛛抱蛋,而非黄花蜘蛛抱蛋。     

Development and characterization of microsatellite loci in the endangered Tricyrtis ishiiana (Convallariaceae), a local endemic plant in Japan

Nine microsatellite loci were isolated and characterized for the endangered and tertiary relict perennial herb, Tricyrtis ishiiana. The number of alleles ranged from 2 to 33. The expected (H _E) and observed (H _O) heterozygosities were 0.207–0.944 and 0.215–0.813, respectively, from 96 individuals on one population. Five loci exhibited significantly fewer heterozygotes than expected under Hardy–Weinberg equilibrium (P < 0.05). These primers amplifying microsatellites in this species may provide a useful tool for population genetics to establish conservation strategy.     

Molecular phylogenetics of Ruscaceae sensu lato and related families (Asparagales) based on plastid and nuclear DNA sequences

Background

Previous phylogenetics studies of Asparagales, although extensive and generally well supported, have left several sets of taxa unclearly placed and have not addressed all relationships within certain clades thoroughly (some clades were relatively sparsely sampled). One of the most important of these is sampling within and placement of Nolinoideae (Ruscaceae s.l.) of Asparagaceae sensu Angiosperm Phylogeny Group (APG) III, which subfamily includes taxa previously referred to Convallariaceae, Dracaenaaceae, Eriospermaceae, Nolinaceae and Ruscaceae.

Methods

A phylogenetic analysis of a combined data set for 126 taxa of Ruscaceae s.l. and related groups in Asparagales based on three nuclear and plastid DNA coding genes, 18S rDNA (1796 bp), rbcL (1338 bp) and matK (1668 bp), representing a total of approx. 4·8 kb is presented. Parsimony and Bayesian inference analyses were conducted to elucidate relationships of Ruscaceae s.l. and related groups, and parsimony bootstrap analysis was performed to assess support of clades.

Key Results

The combination of the three genes results in the most highly resolved and strongly supported topology yet obtained for Asparagales including Ruscaceae s.l. Asparagales relationships are nearly congruent with previous combined gene analyses, which were reflected in the APG III classification. Parsimony and Bayesian analyses yield identical relationships except for some slight variation among the core asparagoid families, which nevertheless form a strongly supported group in both types of analyses. In core asparagoids, five major clades are identified: (1) Alliaceae s.l. (sensu APG III, Amarylidaceae–Agapanthaceae–Alliaceae); (2) Asparagaceae–Laxmanniaceae–Ruscaceae s.l.; (3) Themidaceae; (4) Hyacinthaceae; (5) Anemarrhenaceae–Behniaceae–Herreriaceae–Agavaceae (clades 2–5 collectively Asparagaceae s.l. sensu APG III). The position of Aphyllanthes is labile, but it is sister to Themidaceae in the combined maximum-parsimony tree and sister to Anemarrhenaceae in the Bayesian analysis. The highly supported clade of Xanthorrhoeaceae s.l. (sensu APG III, including Asphodelaceae and Hemerocallidaceae) is sister to the core asparagoids. Ruscaceae s.l. are a well-supported group. Asparagaceae s.s. are sister to Ruscaceae s.l., even though the clade of the two families is weakly supported; Laxmanniaceae are strongly supported as sister to Ruscaceae s.l. and Asparagaceae. Ruscaceae s.l. include six principal clades that often reflect previously named groups: (1) tribe Polygonateae (excluding Disporopsis); (2) tribe Ophiopogoneae; (3) tribe Convallarieae (excluding Theropogon); (4) Ruscaceae s.s. + Dracaenaceae + Theropogon + Disporopsis + Comospermum; (5) Nolinaceae, (6) Eriospermum.

Conclusions

The analyses here were largely conducted with new data collected for the same loci as in previous studies, but in this case from different species/DNA accessions and greater sampling in many cases than in previously published analyses; nonetheless, the results largely mirror those of previously conducted studies. This demonstrates the robustness of these results and answers questions often raised about reproducibility of DNA results, given the often sparse sampling of taxa in some studies, particularly the earliest ones. The results also provide a clear set of patterns on which to base a new classification of the subfamilies of Asparagaceae s.l., particularly Ruscaceae s.l. (= Nolinoideae of Asparagaceae s.l.), and examine other putatively important characters of Asparagales.     

Phylogeny of Agavaceae based on ITS rDNA sequence variation

Several systems of classification have been proposed for the family Agavaceae. A distinctive bimodal karyotype and similarities of fruits and seeds strongly support close relationships among Yucca, Hesperaloë, Beschorneria, Furcraea, Agave, Manfreda, Polianthes, Prochnyanthes, and perhaps Hosta. However, Dasylirion, Beaucamea, Nolina, Calibanus, Dracaena, and Sansevieria differ in so many cytological and morphological features that many have concluded they should be excluded from Agavaceae and separated into two families, Nolinaceae and Dracaenaceae. Chloroplast DNA restriction site data support these separations and indicate that Nolinaceae and Dracaenaceae are very close to Convallariaceae (Maianthemum, Convallaria, Aspidistra, Liriope, etc.). In this paper we report the results of an ITS rDNA sequencing study of 40 taxa in Agavaceae sensu lato and related groups in the order Asparagales. Sequence alignments were optimized using the Consistency Index, Retention Index, and Rescaled Consistency Index to find the alignment that exhibited the least amount of homoplasy. The results of our study are congruent with the conclusions drawn from cytological, immunological, cpDNA, and rbcL studies, which support a narrow interpretation of Agavaceae and a close relationship among Convallariaceae, Dracaenaceae, and Nolinaceae. In addition, the ITS sequence data provide evidence for some interesting relationships within these families.