关于兰科盆距兰属与囊唇兰属的混淆问题

回顾盆距兰属(Gastrochilus)与囊唇兰属(Saccolabium)两个混淆属的简史。它们为彼此明显不同的独立属。盆距兰属的唇瓣为半球形囊状,侧裂片不明显,中裂片甚大;蕊柱无足;花粉团具孔隙。囊唇兰属的唇瓣为圆筒状距形,侧裂片明显,中裂片很小;蕊柱有短足;花粉团实心。前者广泛分布于亚洲热带与亚热带地区;后者则只局限于印度尼西亚的爪哇与苏门答腊。因此,建议在国际命名法规中取消保留名Saccolabium以及作为其异名的废弃名Gastrochilus(1822号)。     

广东山区兰科植物区系的研究

初步统计 ,广东山区共有兰科植物 71属 2 0 8种。其中以热带分布属 4 7属 ( 66.2 % )为主 ,占绝对优势 ,其次为热带—亚热带属 1 3属 ( 1 8.3% )。主要属为虾脊兰属、羊耳蒜属、玉凤花属、石斛属、兰属、石豆兰属 ,其中 2属为世界分布属 ,2属为热带分布属 ,2属为热带—亚热带分布属。广东山区兰科植物区系的地理成分较为复杂、多样 ,以热带亚洲成分 (占 39.4 % )为主导成分 ,其次为热带亚洲至热带大洋洲分布成分 ( 1 6.9% )。广东山区没有特有属 ,但特有种丰富 ,产中国特有种 39种 (占 1 8.8% ) ,其中广东特有种 6种 (占 2 .9% )。广东山区具有兰科植物从最原始到最进化各类型的代表。区系成份比较表明 ,本区与云南、广西和中南半岛兰科植物区系有较密切的联系。结果表明本区兰科植物区系的古老原始性 ;具有从热带向亚热带过渡的特点 ;与热带亚洲兰科植物区系具有密切的关系 ;可能是中国兰科植物演化中心的一部分。     

兰科一新属和新亚族——丫瓣兰属和丫瓣兰亚族

基于丫瓣兰Ypsilorchis fissipetala (Finet)Z.J.Liu,S.C.Chen &L.J.Chen(基名为裂瓣羊耳蒜Liparis fissipetala Finet)建立了兰科新属--丫瓣兰属Ypsilorchis Z.J.Liu,S.C.Chen&.J.Chen.新属与羊耳蒜属Liparis的区别点为:新属有两个粉蜡质花粉团:每个花粉团具1个多少有弹性的花粉团柄;花瓣二深裂;叶具强烈波状的边缘,其先端有一个长达1 mm的芒尖.这些特征表明了其与羊耳蒜亚族Liparidinae有明显的差别,为此,建立了一个新的亚族--丫瓣兰亚族Ypsilorchidinae Z.J.Liu,S.C.Chen &L.J.Chert.     

中国兰科大苞兰属一新记录种——淡黑大苞兰

大苞兰属全世界共有23种,主要分布于东南亚各国。我国分布有12种,可以说是该属的分布中心。在2011－2013年期间,对普洱地区兰科植物的野外考察中,发现了该属一个新记录种 Sunipia nigricans Avery-anov,根据该种拉丁名种加词之意将其定为“淡黑大苞兰”。淡黑大苞兰主要特点是花淡黑色、粘盘柄不分叉、顶部连接着4个球形的花粉团,与该属其它所有种类有明显区别。     

中国隔距兰属(兰科)一新记录(英文)

隔距兰属(Cleisostoma Bl.)是兰科植物中较大的一个属,约有100种,广泛分布于热带、亚热带地区。中国约有16种,其中4种为特有。该文报道了该属一中国新记录——二齿叶隔距兰[Cleisostoma aspersum(Rchb.f.)Garay],并提供描述和照片,目前该种仅见于云南。与近缘种类相比,本种具有以下鉴别特征:叶齿状二裂;唇瓣中裂片肥厚,前缘钝;蕊喙圆锥状,先端歪斜;药帽喙状等。在花部形态上,该种与Cleisostoma discolor Lindl.相似,然而后者的唇瓣中裂片明显较薄,匙状方形,并且具有啮齿状边缘,易于区别。     

中国兰科一新记录属——袋距兰属

报道了中国兰科一新记录属——袋距兰属(Lesliea).袋距兰原记载分布于泰国,现发现中国云南西双版纳也有分布,与近缘属的主要区别为距袋状、蕊喙长而二裂、粘盘柄倒圆锥状等.     

角唇隔距兰,中国隔距兰属(兰科)一新记录种

报道了中国兰科(Orchidaceae)隔距兰属(Cleisostoma Blume)一新记录种:角唇隔距兰(C.tricornutum Averyanov)。该种与C.crochetii(Guillaumin)Garay、C.parishii(J.D.Hooker)Garay相近,因其有不分枝的线状花粉团柄、球状的花粉团块和一个先端短喙状的半球形药帽而与C.crochetii(Guillaumin)Garay相区别;因其有松散、罕分枝的花序,长角状的唇瓣侧裂片而与C.parishii(J.D.Hooker)Garay相区别。提供了新记录种的形态描述及图片。     

中国鸢尾兰属(兰科)二新记录

报道了中国兰科(Orchidaceae)植物二新记录种,即镰叶鸢尾兰(Oberonia falcata King & Pantl.)和坎布里鸢尾兰(O.kanburiensis Seidenf.)。镰叶鸢尾兰茎较长,叶镰曲状,萼片反折,唇瓣中裂片二裂呈锐角,先端尖;坎布里鸢尾兰花瓣及唇瓣边缘流苏状,唇瓣中部缢缩,在中裂片先端最宽。     

中国兰科二新记录种

兰科植物资源调查是掌握地区兰科本底资料的基础,对研究兰科植物的地理分布和资源多样性具有重要意义.该文报道了分别产自中国西藏自治区墨脱县和巴宜区的石豆兰属(Bulbophyllum Thou.)中国分布新记录种——尼泊尔大苞兰(B.raskotii J.J.Verm.,Schuit.&de Vogel)和曲唇兰属[Pan...     

东南亚兰科植物的物种多样性、生活习性及其传粉系统（附表）

兰科(Orchidaceae)植物广布于除两极和极端沙漠地区外的各种陆地生态系统,包括5个亚科800多属28 000多种。东南亚地区兰科植物种数约占世界的1/3,是兰科植物生物多样性热点区域之一。通过查阅文献及书籍等资料,该文系统整理了东南亚兰科植物物种种类及其扩散演化历史,并对其生活习性和传粉系统进行了归类。结果表明:(1)东南亚兰科植物8 855种,分属5亚科17族26亚族240属;(2)主要生活型为附生的有127属6 000种以上,地生97属2 000种以上,腐生13属约100种,藤本4属40余种;(3)根据整理出的东南亚79个属的兰科植物传粉系统发现,有44个属含有自动自交的物种,具报酬物的传粉系统有花粉(仅见于拟兰亚科)、芳香类物质(仅见于香荚兰亚科)和花蜜(5个亚科均有)等报酬物类型。欺骗性传粉系统广泛存在于各个亚科,包括食源性欺骗、性拟态、繁殖地拟态和信息素拟态等类型。东南亚兰科植物在物种、生活习性及传粉系统都展现出极高的多样性,对这些生物学特点的总结将为兰科植物的保育提供一定的理论基础和本底资料。     

Chenorchis, a new orchid genus, and its eco-strategy of ant pollination

Chenorchis, a new orchid genus belonging to C. singchii with tropical orchid features, was found in subtropical regions of Gaoligong Mountain in Yunnan Province, China. This taxon undoubtedly belongs to Trib. Vandeae due to its comparatively advanced epiphytic and monopodial characteristics with very hard pollinia and long stipe. It is akin to Ascocentrum and Holcoglossum, from which it differs by its lip lacking appendage, side-lobes arising from both sides of the mid-lobe rather than the entrance to the spur; large stigmatic cave; very large rostellum, conspicuously broader than the column, spreading downward; pollinia each with a distinct caudicle attached to the incurved subterminal portion of a common stipe. Phylogenetic analysis shows that it may be of tropical region originally and evolve into a new genus due to changed environment, indicating that the main motivation of angiosperm differentiation is to bring forth more ecological opportunities. A further examination of reproductive ecology, especially pollination mechanism and breeding system, proved that this species has formed many mechanisms to promote selfing and inbreeding, such as symbiosis with ants (Temnothorax sp.), utilization of ants for short-distant pollination, opening of flowers simultaneously to increase the frequency of geitonogamy, efficient dispersal and growth of seeds, and crowded communities to improve the possibility of inbreeding. All the adaptive changes above turn into necessary conditions for their survival in subtropical regions. The reproductive strategy of this unique life history shows that this immigrant species autonomously passes the genes on to future generations to remain their adaptability, by quickly occupying the habitat. It is a successful strategy in habitat expansion that inflorescence produces a lot of flowers to facilitate geitonogamy, whose significance may extend to provide evidence that the occurrence of plants' sex results from the trade-offs of the fluctuation of habitat in evolution.     

Breeding system and factors limiting fruit production in the nectarless orchid Broughtonia lindenii

Low fruit set values in most orchids (especially epiphytic and tropical species) are normally thought to be the consequence of pollination constraints and limited resources. In particular, pollination constraints are modulated by pollinator visitation rates, pollinator visitation behaviour (promoting crossing or selfing), the type and number of pollinia deposited on stigmas (in the case of orchids with subequal pollinia) and the amount of pollen loaded per inflorescence. In order to assess to what extent these factors can affect fruit set in specific orchid-pollinator systems, the repercussions of some of these aspects on reproduction of Broughtonia lindenii were examined in a coastal population in western Cuba. The study focused on plant breeding system, importance of pollen load and type of pollinia on subsequent fruit and seed, limiting factors of seed production and interaction with pollinators. This species presents long-lasting flowers that senesce after all forms of effective visit. Pollinator dependence for fruit production was demonstrated, while hand-pollination experiments revealed self-compatibility and inbreeding depression at seed level. More pollinia on stigmas enhance the proportion of well-developed seeds. In contrast, the pollinia type used in pollination is not important for seed quality of fruits, suggesting that small pollinia are not rudimentary. Natural fruit set in two consecutive years was substantially affected by pollinator activity, and also by systematic depredatory activity of ants and a caterpillar. Considering that this orchid completely lacks nectar and that the local assemblage of pollinators and predators influenced its reproduction, a minor importance of resource constraints in this epiphyte (with long-lasting reserve structures) is confirmed at least for a short time.     

Preventing inbreeding depression in Anacamptis coriophora (Orchidaceae) as a model of food-rewarding orchid

Pollination of deceptive orchids has enabled scientists to understand how these species avoid inbreeding depression by reducing the number of pollinator visits per inflorescence. In rewarding species, which receive a higher rate of visits per plant, geitonogamy is usually higher and therefore the risk of inbreeding increases. In this study, we assess the breeding system of the rewarding orchid A. coriophora, and the spatio-temporal changes in its fitness as well as variation in nectar content after pollination. We found that the species partially selects allogamous pollen if pollinia from the same stalk and other plants arrive to the stigma. Furthermore, when self-pollination occurs, despite successful fructification, seed viability is significantly lower than that of cross-pollinated plants. A. coriophora exhibits spatio-temporal variation in fitness that does not correlate with any plant feature. Moreover, nectar volume is reduced after pollination, but the sugar concentration is maintained. This study emphasizes how essential the pre-zygotic and post-zygotic reproductive barriers are for rewarding orchids to avoid inbreeding depression.

     

A supplementary contribution of ants in the pollination of an orchid, Epipactis thunbergii, usually pollinated by hover flies

It has been controversial how extensively ants contribute to pollination, and we evaluated the contribution of the Japanese carpenter ant, Camponotus japonicus, to the pollination of an orchid, Epipactis thunbergii. Two-year field studies revealed that (1) the ant workers foraged even in cool/cloudy conditions and accordingly visited orchid flowers more frequently (about 40% of all the visitors) than hover flies, the principle pollinators (10–20%), and that (2) the flower-visiting ants occasionally removed pollinia from the anther and then delivered pollen onto the stigmatic surface of other flowers, although self-pollination might frequently occur in the consecutive visits of flowers within an inflorescence. An artificial pollination experiment with pollinia which had been transferred to the ant integument showed that (3) the treated flowers produced as many fruits and seeds as control flowers. We concluded that C. japonicus workers could actually pollinate E. thunbergii flowers and their relative importance as pollinators appeared to be largely dependent on the abundance of flower-visiting workers or weather conditions during the flowering period, which mainly determined the availability of hover flies.     

A nocturnal Provespa wasp species as the probable pollinator of epiphytic orchid Coelogyne fimbriata

Many vespid wasps visit flowers to forage nectar. These hymenopterans sometimes contribute to flower pollination. However, none of the nocturnal wasp species is a known pollinator. We collected individuals of light‐attracted Provespa nocturna workers in a montane rainforest on Peninsular Malaysia: some wasps collected bore orchid pollinia on their thoraxes. Among 114 trapped individuals, four bore pollinaria and nine bore only viscidia, suggesting that pollinia had been successfully transported. Molecular barcoding of the pollinia (based on their ITS sequences) assigned the orchid to a species in Coelogyne fimbriata complex. These findings and our other analyses suggest that this nocturnal wasp contributes to pollination of an epiphytic nectarless orchid that probably releases olfactory attractants. This discovery sheds light on the importance of mutualistic relationships between the nocturnal social wasps and epiphytic orchids in Southeast Asian tropical rainforest canopies.     

A new technique for monitoring pollen flow in orchids

Summary The orchid Prasophyllum fimbria is pollinated by nectar-feeding native bees and wasps. The pollinia are patially separated from the viscidium by a stipe so that pollinia can be labelled with coloured histochemical stains without interfering with pollinarium removal. Pollen flow was monitored by following the movement of the coloured pollen in several populations of P. fimbria in Western Australia. Statistical analysis confirmed that pollen labelling did not interfere with pollinarium removal or subsequent pollination of the labelled flower. Fifty eight labelled pollinaria were removed by vectors from 16 test spikes, with a total of 125 flowers on 47 spikes receiving labelled pollen. An average of 2 flowers received pollen for every pollinium removed but up to 6 flowers received pollen from a single collinium. No significant differences between mean vector flights and pollen flow distances were detected. On average, geitonogamous transfers only accounted for 22% of all pollinations. This is a simple and inexpensive technique for the direct labelling of pollen with minimal disruption to the pollination system and may have applications in other plant families.     

Mast fruiting in a hawkmoth-pollinated orchid Habenaria glaucifolia: an 8-year survey

Aims The hypothesis of predator satiation has been proposed to explain mast fruiting in various flowering plants. It considers that the simultaneous production of large numbers of seeds by a plant population reduces the risk of seed predation for each individual. Orchids produce huge numbers of seeds per fruit and rarely experience seed predation. It remains unclear which factors may affect fluctuating fruit production in orchids, which generally suffer a widespread pollen limitation. To explore the temporal pattern of fruiting and potential factors related to fluctuation in fruit production, we investigated reproductive success of a long-spurred orchid (Habenaria glaucifolia) in an alpine meadow with thousands of individuals over 8 years.Methods To estimate reproductive success, pollinator observation was conducted by day and at night, and pollinia removal and receipt were recorded in the field population for 8 years. To examine whether fruit set and seed set are pollen limited, we conducted supplementary pollination experiments and compared fruit set, seed set and pollinia movement of open-pollinated flowers from 2011 to 2013. We measured lengths of spurs and pollinator proboscises, and nectar volume and concentration, to identify potential pollinators.Important findings Hawkmoths were seen to be effective pollinators for H. glaucifolia in 3 years, whereas in the remaining 5 years no pollinators were observed, and consequently pollinia were rarely transferred. Numerous pollinia movements were observed in 2012, 2013 and 2014 (pollinia removal: 48, 59 and 85%; pollinia receipt 51, 70 and 80%), and correspondingly fruit set was significantly higher in 2012 and 2013 (59 and 46%) than in 2011 (25%). It was fruit set, rather than seed set, that was pollen limited in this orchid in the 3 years, in that supplementary pollination increased fruit set but did not increase seed set per fruit compared to natural. Three species of hawkmoths had proboscis lengths that matched the spur length of H. glaucifolia. Fruit set in this long spurred orchid depends on the activity of long-tongued hawkmoths, resulting in significant temporal variation in fruit production. Mast fruiting in this alpine orchid could be attributed to a 'sit and wait' strategy, awaiting an abundance of effective pollinators.     

What We Think We Know vs. What We Need to Know About Orchid Pollination and Conservation: <Emphasis Type="Italic">Cypripedium</Emphasis> L. as a Model Lineage

While Darwin (1862, 1877) showed that reproductive success in orchid populations depended on adaptive floral morphology coupled with pollinator visitation a more recent review of the literature (Tremblay et al., 2005) confirmed that many out-breeding species are pollinator-limited because most orchid species showing low fecundity also lack rewards. The absence of rewards depresses both pollinator fidelity and the frequency of pollinator visits to an orchid population even though orchid flowers that lack rewards retain the same interlocking floral structures for precise pollinia removal and deposition found in related species that offer rewards. Using the genus, Cypripedium, as a model lineage of non-rewarding flowers this study also shows that the correlation between low fruit set in a Cypripedium sp. and its specific pollinator(s) is insufficient to predict specific frequencies of low fecundity. Annual rates of fruit set often vary broadly between populations of the same species and within the same population over several seasons. We speculate that fruit-set rates also decline when orchid demography and additional biotic and abiotic factors interrupt rates of pollinator activity (pre-zygotic) and fertilization/fruit maturation (post-zygotic). We suggest that that traditional field studies on pollination ecology and breeding systems be combined with data sets recording genetic variation and orchid flower demography in relation to seasonal variation in climate. We also propose that the same information be collected in regard to genetic variation, demography and phenology of populations of known orchid pollinators and co-blooming angiosperm species native to orchid habitats.     

Pollinarium morphology and floral rewards in Brazilian Maxillariinae (Orchidaceae)

BACKGROUND AND AIMS: There is strong support for the monophyly of the orchid subtribe Maxillariinae s.l., yet generic boundaries within it are unsatisfactory and need re-evaluation. In an effort to assemble sets of morphological characters to distinguish major clades within this subtribe, the pollinarium morphology and floral rewards of representative Brazilian species of this subtribe were studied. METHODS: The study was based on fresh material from 60 species and seven genera obtained from cultivated specimens. Variation of pollinarium structure and floral rewards was assessed using a stereomicroscope and by SEM analysis. KEY RESULTS: Four morphological types of pollinaria are described. Type 1 appears to be the most widespread and is characterized by a well-developed tegula. Type 2 lacks a stipe and the pollinia are attached directly to the viscidium. Type 3 also lacks a stipe, and the viscidium is rigid and dark. In Type 4, the stipe consists of the whole median rostelar portion and, so far, is known only from Maxillaria uncata. Nectar, trichomes, wax-like and resin-like secretions are described as flower rewards for different groups of species within the genus Maxillaria. Data on the biomechanics and pollination biology are also discussed and illustrated. In Maxillariinae flowers with arcuate viscidia, the pollinaria are deposited on the scuttellum of their Hymenopteran pollinators. In contrast, some flowers with rounded to rectangular, pad-like viscidia fix their pollinaria on the face of their pollinators. CONCLUSIONS: Pollinarium morphology and floral features related to pollination in Brazilian Maxillariinae are more diverse than previously suggested. It is hoped that the data presented herein, together with other data sources such as vegetative traits and molecular tools, will be helpful in redefining and diagnosing clades within the subtribe Maxillariinae.     

Orthoptera, a new order of pollinator

Background and Aims

Pollinator-mediated selection and evolution of floral traits have long fascinated evolutionary ecologists. No other plant family shows as wide a range of pollinator-linked floral forms as Orchidaceae. In spite of the large size of this model family and a long history of orchid pollination biology, the identity and specificity of most orchid pollinators remains inadequately studied, especially in the tropics where the family has undergone extensive diversification. Angraecum (Vandeae, Epidendroideae), a large genus of tropical Old World orchids renowned for their floral morphology specialized for hawkmoth pollination, has been a model system since the time of Darwin.

Methods

The pollination biology of A. cadetii, an endemic species of the islands of Mauritius and Reunion (Mascarene Islands, Indian Ocean) displaying atypical flowers for the genus (white and medium-size, but short-spurred) was investigated. Natural pollinators were observed by means of hard-disk camcorders. Pollinator-linked floral traits, namely spur length, nectar volume and concentration and scent production were also investigated. Pollinator efficiency (pollen removal and deposition) and reproductive success (fruit set) were quantified in natural field conditions weekly during the 2003, 2004 and 2005 flowering seasons (January to March).

Key Results

Angraecum cadetii is self-compatible but requires a pollinator to achieve fruit set. Only one pollinator species was observed, an undescribed species of raspy cricket (Gryllacrididae, Orthoptera). These crickets, which are nocturnal foragers, reached flowers by climbing up leaves of the orchid or jumping across from neighbouring plants and probed the most ‘fresh-looking’ flowers on each plant. Visits to flowers were relatively long (if compared with the behaviour of birds or hawkmoths), averaging 16·5 s with a maximum of 41·0 s. At the study site of La Plaine des Palmistes (Pandanus forest), 46·5 % of flowers had pollen removed and 27·5 % had pollinia deposited on stigmas. The proportion of flowers that set fruit ranged from 11·9 % to 43·4 %, depending of the sites sampled across the island.

Conclusions

Although orthopterans are well known for herbivory, this represents the first clearly supported case of orthopteran-mediated pollination in flowering plants.