Chloroplast genomic diversity in Bulbophyllum section Macrocaulia (Orchidaceae,Epidendroideae, Malaxideae): Insights into species divergence and adaptive evolution

Bulbophyllum is the largest genus in Orchidaceae with a pantropical distribution. Due to highly significant diversifications, it is considered to be one of the most taxonomically and phylogenetically complex taxa. The diversification pattern and evolutionary adaptation of chloroplast genomes are poorly understood in this species-rich genus, and suitable molecular markers are necessary for species determination and phylogenetic analysis. A natural Asian section Macrocaulia was selected to estimate the interspecific divergence of chloroplast genomes in this study. Here, we sequenced the complete chloroplast genome of four Bulbophyllum species, including three species from section Macrocaulia. The four chloroplast genomes had a typical quadripartite structure with a genome size ranged from 156,182 to 158,524 bp. The chloroplast genomes included 113 unique genes encoding 79 proteins, 30 tRNAs and 4 rRNAs. Comparison of the four chloroplast genomes showed that the three species from section Macrocaulia had similar structure and gene contents, and shared a number of indels, which mainly contribute to its monophyly. In addition, interspecific divergence level was also great. Several exclusive indels and polymorphism SSR loci might be used for taxonomical identification and determining interspecific polymorphisms. A total of 20 intergenic regions and three coding genes of the most variable hotspot regions were proposed as candidate effective molecular markers for future phylogenetic relationships at different taxonomical levels and species divergence in Bulbophyllum. All of chloroplast genes in four Bulbophyllum species were under purifying selection, while 13 sites within six genes exhibited site-specific selection. A whole chloroplast genome phylogenetic analysis based on Maximum Likelihood, Bayesian and Parsimony methods all supported the monophyly of section Macrocaulia and the genus of Bulbophyllum. Our findings provide valuable molecular markers to use in accurately identifying species, clarifying taxonomy, and resolving the phylogeny and evolution of the genus Bulbophyllum. The molecular markers developed in this study will also contribute to further research of conservation of Bulbophyllum species.     

中国石豆兰属(兰科)二新记录

报道了中国兰科石豆兰属2新记录种,即普洱石豆兰(Bulbophylhum didymotropis Seidenf)和版纳石豆兰(Bulbophylhum protractum HK.f),并提供描述和图片.     

中国兰科石豆兰属(Bulbophyllum)二新种(英文)

对兰科(Orchidaceae)石豆兰属(Bulbophyllum)二新种,副萼石豆兰(B.malipoense Z.J.Liu,L.J.ChenW.H.Rao)和小副萼石豆兰(B.minor Z.J.Liu,L.J.ChenW.H.Rao)作了描述和绘图。该二新种属于石豆兰属副萼组(Bulbophyllumsection BisetaJ.J.Verm.ex N.Pearce,P.J.CribbJ.Renz),与该组的刺萼石豆兰(B.bisetum Lindl.)相似,区别在于两新种的叶片先端二裂和唇瓣无毛。小副萼石豆兰与副萼石豆兰的区别在于假鳞茎椭圆球形;叶片卵状椭圆形,长1.2～2 cm;侧副萼片较短,长约1 mm;中副萼片几乎与两侧萼片边缘合生。     

Extremely Low Levels of Allozyme Variation in Southern Korean Populations of the Two Rare and Endangered Lithophytic or Epiphytic <Emphasis Type="Italic">Bulbophyllum Drymoglossum</Emphasis> and <Emphasis Type="Italic">Sarcanthus Scolopendrifolius</Emphasis> (Orchidaceae): Implications for Conservation

Allozyme variation was investigated in two local populations of Bulbophyllum drymoglossum and three populations Sarcanthus scolopendrifolius, two rare and endangered lithophytes and epiphytes from South Korea. Genetic diversity was extremely low within populations (mean H _e = 0.011 for B. drymoglossum; 0.002 for S. scolopendrifolius). Among the putative screened 21 loci, we found only one polymorphic locus for each species. Only one polymorphic locus, detected just one population of each species, revealed significantly high degree of population differentiation between and among populations (F _ST = 0.253 for B. drymoglossum and F _ST = 0.899 for S. scolopendrifolius). These results suggest that genetic drift (consequence of a very small effective population size), coupled with a limited gene flow would play a major role in shaping population genetics of these species in South Korea. The current status of both species (small population sizes, spatially isolated populations, and highly localized habitats) in addition to the extremely low levels of genetic diversity and reckless collection of endangered orchids by plant sellers, significantly threaten the long-term survival of these species in Korea. Conservation of the two species requires both in situ strategies, by introducing of genets to increase effective population sizes by minimizing adverse effects (e.g., outbreeding depression and genetic swamping by non-native genotypes), and ex situ strategies, such as collection of genets from clonal ramets.     

我国石豆兰属药用植物资源及其保护

描述了石豆兰属15种野生药用植物的分布及其生物学特性、资源现状、药用价值等。石豆兰属药用植物是我国民间常用的中草药,主要分布于我国的华南、西南地区,其中云南、广东、广西分布较多,云南最多,有12种,占我国野生石豆兰属药用资源的80％。不同的种类在各地的资源蕴藏量不同,广东石豆兰、密花石豆兰在广东、广西常见,芳香石豆兰在广东常见。近年来,石豆兰的野生资源被当作药材和观赏花卉遭到滥采乱挖,受到不同程度的破坏。对如何保护与合理利用石豆兰属药用植物资源提出了建议。     

中国兰科植物新资料

报道了中国兰科(Orchidaceae)一新记录种——白苞石豆兰（Bulbophyllum albibracteum Seidenf.）,它的主要特征是花苞片白色,大且显著,外弯,边缘具细锯齿;萼片背面沿中脉具短毛;蕊柱齿直立细长,长达1 mm。鞍唇沼兰（Malaxis matsudai (Yamamoto) Hatusima）与全唇叉柱兰（Cheirostylis takeoi(Hayata) Schltr.）为中国大陆新记录。     

石豆兰属植物化学成分及药理活性研究进展

石豆兰属植物由于近年来同科石斛属植物的过度采挖,而作为名贵中药石斛类药材使用。为了解其化学成分及能否替代石斛,对石豆兰属植物的化学成分及药理活性研究进展进行了综述。研究表明,从石豆兰属植物一共分得化合物60多个,包括菲类、联苄、苯丙素、黄酮、甾体和挥发性成分等结构类型。药理实验表明．广东石豆兰具有抗肿瘤作用。开展国产石豆兰属植物的研究,对发现新的药用活性成分及资源保护有重要意义。     

中国兰科植物研究杂记

中国西藏墨脱县位于东喜马拉雅和印缅交界地区,是雅鲁藏布江大峡谷国家级自然保护区的核心区域,是喜马拉雅生物多样性热点地区之一。该文通过对中国西藏墨脱的科学考察,报道了中国兰科植物2个新记录种,即西藏牛角兰(Ceratostylis radiata)和格当石豆兰(Bulbophyllum psychoon),并提供了描述和图片。西藏牛角兰花为纯白色,花辐射对称,唇瓣3裂,茎长2~2.5 cm,明显区别于该属内其他种。格当石豆兰与齿瓣石豆兰(Bulbophyllum levinei)相似,但不同之处在于格当石豆兰的花瓣卵形,先端锐尖。凭证标本分别保存于西藏自治区高原生物研究所(XZ)和中国科学院植物研究所(PE)标本馆中。2个新记录种原分布均在印度、缅甸和越南等地区,在中国西藏的发现说明了中国西藏墨脱的植物区系和原分布地有一定的关系,同时也印证了中国西藏墨脱属于亚热带地区,且2个新记录种的分布海拔超出了原分布地范围,开花的时间也相对推迟。此新记录种的发现对摸清该区植物种类和丰富中国西藏植物区系提供了更加详实的资料。     

中国兰科石豆兰属一新种

描述了中国石豆兰属Bulbophyllum一新种——天贵卷瓣兰(Bulbophyllum tianguii K.Y.Lang & D.Luo),并提供墨线图。该种产于广西乐业县,与富宁卷瓣兰B.funingense Z.H.Tsi & S.C.Chen外貌颇相似,但中萼片先端渐尖并具3 mm长的芒,侧萼片宽4~4.5 mm,花瓣先端渐尖并具1.5 mm长的芒,唇盘具2条肉质、具缘毛的纵脊,可与后者明显区别。