黔产天麻的化学成分

从黔产天麻（Ｇａｓｔｒｏｄｉａ ｅｌａｔａ Ｂｌ．）中分离得到１个新的含氮化合物，命名为天麻羟胺（ｇａｓｔｒｏｄａｍｉｎｅ，Ⅰ），经波谱分析，确定其结构为双－（对羟苄基）羟胺。除β－谷甾醇和胡萝卜甙外，同时还分离鉴定了３个已知化合的：Ｌ－焦谷氨酸（Ⅱ）、柠檬酸单甲酯（Ⅲ）、柠檬酸双甲酯（Ⅳ），其中化合物Ⅱ和Ⅳ为首次报道从天麻中得到的。  

Recent developments in the study of orchid mycorrhiza

Orchids are mycoheterotrophic during their seedling stage and in many species the dependency on fungi as a carbohydrate source is prolonged into adulthood. The mycobionts in orchid mycorrhiza belong in at least 5 major taxonomic groups of basidiomycetes. Traditional records have mainly focused on saprotrophic mycobionts but the participation of both ectomycorrhizal and parasitic fungi in orchid mycorrhiza has been corroborated. There is an increasing evidence of specific relationships between orchids and fungi, though usually not on a species-to-species level. Physiological compatibility demonstrated under artificial conditions, as in vitro, may be much broader, however. Recent development of field sowing techniques has improved the possibilities of evaluating orchid-fungal relations in an ecological context. Although the general nutrient flow in orchid mycorrhiza is well known, some questions remain regarding breakdown processes of fungi within orchid tissues, especially the ptyophagic syndrome that has recently been illustrated at the ultrastructural level for the first time.  

初论中国兜兰属植物的保护策略及其潜在资源优势

兜兰属植物是最受人们喜爱的兰科植物之一 ,中国是兜兰属植物的主要产地。与世界其他地区一样 ,我国兜兰属植物也面临持续的商业采集压力。本文回顾了世界兜兰属植物的贸易、栽培和育种的历史 ,认为有菌播种方法可以更有效地保护兜兰属植物的多样性 ,同时也能够为兜兰属植物的人工栽培和育种提供新的手段。目前我国兜兰属植物一方面仍遭受各种人为因素的干扰 ,急需采取措施加以保护 ;另一方面对我国兜兰属植物的认识还不够全面和深入 ,还不能对人为因素影响的程度和范围作出客观的评价 ,特别是有关兜兰属植物的繁育技术还很薄弱。针对这种现状 ,作者提出在较长时期内我国兜兰属植物的保护策略宜以原地保护 (insituconservation)为主 ,同时积极开展有关兜兰属植物保护生物学的基础研究 ,大力发展和完善迁地保护 (exsituconservation)技术体系。最后 ,讨论了我国兜兰属植物的潜在资源和生态等方面的优势。  

Variation in sexual reproduction in orchids and its evolutionary consequences: a spasmodic journey to diversification

The great taxonomic diversity of the Orchidaceae is often attributed to adaptive radiation for specific pollinators driven by selection for outcrossing. However, when one looks beyond the product to the process, the evidence for selection is less than overwhelming. We explore this problem by discussing relevant aspects of orchid biology and asking which aspects of reproduction explain the intricate pollination mechanisms and diversification of this family. We reaffirm that orchids are primarily pollination limited, the severity of which is affected by resource constraints. Fruit set is higher in temperate than in tropical species, and in species which offer pollinator rewards than those that do not. Reproductive success is skewed towards few individuals in a population and effective population sizes are often small. Population structure, reproductive success and gene flow among populations suggest that in many situations genetic drift may be as important as selection in fostering genetic and morphological variation in this family. Although there is some evidence for a gradualist model of evolutionary change, we believe that the great diversity in this family is largely a consequence of sequential and rapid interplay between drift and natural selection.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 1–54.  

重要观赏兰科植物的分子生物学研究进展

兰科植物是开花植物中最大的家族之一,分子标记技术应用于兰科植物的分类鉴定和品种鉴别,为兰花的分类提供了分子水平的证据,也为兰花保护策略和措施的制定提供了理论基础.兰科植物表现有高度特异的形态、结构和生理特性,是研究花着色机理和子房发育的理想对象.兰花离体培养开花系统的建立,可以用来探明兰花从营养生长向生殖生长的转变机制,是研究花的分化和发育的理想材料.兰花具有特异的查尔酮合成酶(CHS)基因和二氢叶酸还原酶(DFR)基因等控制花色素的合成,DOHI基因控制石斛兰花芽的形成和提早开花,PHAL039基因和ACC合成酶基因在蝴蝶兰授粉后的子房发育中起着重要的调控作用,这些特异基因的分离和克隆为兰花花的分化、发育及着色机制提供了分子基础.蝴蝶兰属、大花蕙兰(Cymbidium hybrdium)、石斛兰属、文心兰属、五唇兰属和万代兰属等兰科植物都有转基因的研究报道,主要以原球茎为材料采用基因枪或农杆菌法转化,部分研究获得了转化植株.  

真菌在兰科植物种子萌发生长中的作用及相互关系

本文从真菌在兰科种子萌发中的应用、真菌侵染的过程、种子和根系消化真菌的途径及共生真菌的分布等方面,综述了真菌与兰科植物种子萌发及菌根关系的研究进展,讨论了该研究的有关问题及真菌在兰科种子萌发中应用的前景。  

梵净山兰科植物的分类和区系特点

本文根据野外考察和现存国内的标本，记载了我国贵州梵净山４９种，３３属的兰科植物，其中１２属１５种为新纪录。该地区的兰科植物区系显示从热带向温带过渡，与日本较为接近。  

贵州兰科植物增补

对贵州兰科植物区系新资料进行了报道，包括：1个新种(兴仁开唇兰)，1个新记录属(无叶兰属)和15个新记录种。  

兜兰胚胎学的研究

云南兜兰花药壁有五层细胞,绒毡层细胞具双核,属分泌型。小孢子母细胞减数分裂为同时型。四分体中四个小孢子呈四面体或左右对称式排列。成熟花粉为二细胞型。单粒分散的花粉包裹于黄色粘性物质中。生殖细胞最初形成的壁为胼胝质的,待游离到营养细胞质中时,具一层很薄的 PAS 正反应的壁,直到花药开裂时这层壁仍存在。成熟花粉无特化的萌发孔,只具薄壁区。胚珠为薄珠心,具一层珠被,胚囊发育为葱型,成熟胚囊为6—8核,胚发育过程中,具2—4细胞胚柄。胚乳具二核。种子成熟时胚柄及胚乳核都消失。成熟种子只具单层细胞的种皮和一个未分化的球形胚。