Effects of distance from models on the fitness of floral mimics

• Rewardless plants can attract pollinators by mimicking floral traits of rewarding heterospecific plants. This should result in the pollination success of floral mimics being dependent on the relative abundance of their models, as pollinator abundance and conditioning on model signals should be higher in the vicinity of the models. However, the attraction of pollinators to signals of the models may be partially innate, such that spatial isolation of mimics from model species may not strongly affect pollination success of mimics.
• We tested whether pollination rates and fruit set of the rewardless orchid Disa pulchra were influenced by proximity and abundance of its rewarding model species, Watsonia lepida.
• Pollination success of the orchid increased with proximity to the model species, while fruit set of the orchid increased with local abundance of the model species. Orchids that were experimentally translocated outside the model population experienced reduced pollinaria removal and increased pollinator‐mediated self‐pollination.
• These results confirm predictions that the pollination success of floral mimics should be dependent on the proximity and abundance of model taxa, and thus highlight the importance of ecological facilitation among species involved in mimicry systems.

     

In vitro propagation of temperate Australian terrestrial orchids: revisiting asymbiotic compared with symbiotic germination

Using a common temperate herbaceous terrestrial orchid from Australia (Caladenia latifolia) this study investigated 19 asymbiotic media variations comprising four commonly used basal media [half‐strength Murashige and Skoog (½MS), Knudson C (KC), Pa5, and Vacin and Went (VW), with combinations of the plant growth regulators 6‐benzylaminopurine (BA) and α‐naphthalene acetic acid (NAA) or coconut water (CW) and compared their performance with germination on a standard symbiotic germination medium, oatmeal agar (OMA). Percentage germination of seeds every 2 weeks for a total of 8 weeks (five replicates per treatment), time to germination, and growth and development phases in seedlings were recorded. ½MS with 5% (v/v) fresh CW delivered 93% germination, with seedling vigour and development indistinguishable from OMA (95% germination). The same protocol was applied to a further ten species (including the endangered Caladenia huegelii), demonstrating high asymbiotic germination performance (60–93%) across a wide phylogenetic range of terrestrial orchid species. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176 , 556–566.     

达摩兰组织培养适宜培养基的研究

以达摩兰的原种苗茎段为外植体进行组织培养研究,筛选出最适培养基(1)原球茎诱导:MS+6-BA 0.5 mg/L+NAA 1.0 mg/L+香蕉肉250 g/L;(2)丛生芽诱导:1/2 MS+6-BA 3 mg/L+NAA 2.0 mg/L+AC 2.5 g/L+蔗糖3%+香蕉肉200 g/L;(3)芽增殖:1/2 MS+6-BA 3 mg/L+NAA 2.0 mg/L+AC 2.5 g/L+蔗糖3%+香蕉肉150 g/L;(4)根诱导:1/2 MS+6-BA 0.3 mg/L+IBA 0.5 mg/L+NAA 0.5 mg/L+AC 2.5 g/L+蔗糖3%。采用珍珠岩、细石与树皮的混合物为培养基质,移栽成活率达95%以上。     

四川黄龙沟森林植被中兰科植物群落优势种种间联结和相关分析

四川黄龙沟内分布着十分丰富的兰科植物(19属30余种),并且部分种类在沟内形成优势群落。目前尚不清楚在群落中这些兰科植物种之间作用关系。运用种间关联分析和相关分析对黄龙沟森林植被兰科植物群落中的24个优势种的种间关系进行了研究。两种分析方法得到的结果相近,表明黄龙沟优势兰科植物可以分为两组。一组包括无苞杓兰(Cypripedium bardolphianum)、黄花杓兰(C. flavum)、二叶红门兰(Orchis diantha)、广布红门兰(Orchis chusua)、少花虾脊兰(Calanthe delavayi)和西藏杓兰(C. tibeticum),主要分布在光线充足但又具有一定遮荫条件的环境中;另一组包括筒距兰(Tipularia szechuanica)、沼兰(Malaxis monophyllos)、珊瑚兰(Corallorhiza trifida)、小斑叶兰(Goodyera repens)、布袋兰(Calypso bulbosa)、小花舌唇兰(Platanthera minutiflora)和小叶对叶兰(Listera smithii),它们主要分布于荫蔽的环境中。这些兰科植物在组内大多呈现显著的正相关关系,组间大多呈现显著的负相关关系,说明黄龙沟兰科植物在资源利用方式上可能产生了分化。     

Tansley Review No. 110.

S UMMARY 367
I. I NTRODUCTION 367
II. N UMBER 368
III. S IZE 379
IV. A IR SPACE IN THE SEEDS 381
V. F LOATATION AND DISPERSAL 383
1. Air 383
(a) Physical considerations 383
(b) Dispersal 387
(c) Birds 415
2. Water 416
(a) Physical considerations 416
(b) Dispersal 416
VI. C ONCLUSIONS 417
Acknowledgements 417
References 418
Orchid seeds are very small, extremely light and produced in great numbers. Most range in length from c . 0.05 to 6.0 mm, with the difference between the longest and shortest known seeds in the family being 120-fold. The 'widest' seed at 0.9 mm is 90-fold wider than the 'thinnest' one, which measures 0.01 mm (because orchid seeds are tubular or balloon-like, 'wide' and 'thin' actually refer to diameter). Known seed weights extend from 0.31 lg to 24 μg (a 78-fold difference). Recorded numbers of seeds per fruit are as high as 4000000 and as low as 20–50 (80000–200000-fold difference). Testae are usually transparent, with outer cell walls that may be smooth or reticulated. Ultrasonic treatments enhance germination, which suggests that the testae can be restrictive. Embryos are even smaller: their volume is substantially smaller than that of the testa. As a result, orchid seeds have large internal air spaces that render them balloon-like. They can float in the air for long periods, a property that facilitates long-distance dispersal. The difficult-to-wet outer surfaces of the testa and large internal air spaces enable the seeds to float on water for prolonged periods. This facilitates distribution through tree effluates and/or small run-off rivulets that may follow rains. Due to their size and characteristics, orchid seeds may also be transported in and on land animals and birds (in fur, feathers or hair, mud on feet, and perhaps also following ingestion).     

兰属(Cymbidium)5种植物叶结构特征

采用光学显微镜和体视镜,对兰属5种植物（春兰、蕙兰、建兰、寒兰、墨兰）的叶结构特征（叶脉结构、叶表皮结构、解剖结构）进行了观察和测量。结果显示,兰属5种植物的叶脉结构相似,叶表皮结构和解剖结构存在较大差异,其中最主要的差异是皮下纤维束的多少和边缘角质层锯齿形态。依据叶结构特征聚类分析结果,5种兰可分为春兰组、建兰组和墨兰组3组。本研究表明叶结构特征对兰属5种植物的分类具有重要意义。     

菌根真菌─新种─—石斛小菇(英文)

从云南省野生铁皮石斛（Dendrobiumcandidumwall．ExLindl．）根中分离出一菌根真菌,经系统形态学研究后,将其鉴定为小菇属（Mycena）一新种：石斛小菇（Mycenadendrobii）。标本保藏在中国科学院微生物研究所菌物标本室（HMAS）。用石斛小菇伴播12种兰科植物种子,实验结果表明该真菌对天麻（Gastrodiaelata）和密花石斛（Dendrobiumdensdlorum）种子萌发有明显促进作用。     

Evaluating asymbiotic seed culture methods and establishing Disa (Orchidaceae) germinability in vitro: relationships, requirements and first-time reports

Many Disa species (80%) have not been germinated in vitro, fuelling conservation fears. Winter-rainfall species are typically germinable, whilst summer-rainfall species are exclusively intractable in vitro. We aimed to establish the in vitro germination requirements for previously ungerminated Disa species. Conventional asymbiotic seed culture protocols were reviewed and their efficacy in summer-rainfall Disa established. Mature seed was subjected to manipulations of media composition and viscosity, incubation temperature and illumination. Immature cultures were also established across four seed maturity classes. Four first-time germinations (D. cooperi, D. nervosa, D. pulchra and D. woodii) resulted from media with increased water availability. Germination rate (>12 weeks), percentage (<30%) and synchrony were not in accordance with values reported for winter-rainfall species (>80% germination in 8 weeks). Germination of immature seed under control conditions was similar to mature seed germination under modified conditions, but neither percentage approached the calculated germination potential (∼viability). Germination control in Disa is proposed as a trade-off between water availability and the presence of phyto-inhibitors in the environment of the embryo—two features typical of seeds exhibiting water-impermeable dormancy.     

Minituber production from immature seed suspension culture ofOrchis papilionacea

Summary Ripe and immature seeds ofOrchis papilionacea (method I and II, respectively) cultured on modified double strength Curtis medium were assayed for minituber production. Ripe seed germination both on solid and in liquid medium was low and the protocorms obtained developed into white calluses. Germination increased from, 9 to 33% when immature seed suspension culture was used. Protocorms obtained in suspension culture under light developed into minitubers, whereas those obtained on solid media developed into callus. A 30 s ultrasonication of immature seeds 1 wk after suspension, culture initiation further enhanced germination and minituber production. Minitubers had to be transferred and embedded in solid regeneration medium for normal growth.