齿瓣石斛多倍体的诱导初报

采用多倍体育种技术,对云南的野生热带兰花齿瓣石斛(Dendrobium devonianum)进行多倍体诱导试验。利用秋水仙素作为诱导剂,对二倍体试管苗进行诱导,在短期内培育出多倍体植株。用0.03%的秋水仙素处理齿瓣石斛丛生芽24h,其诱导效果最好。观察结果显示:多倍体齿瓣石斛材料在形态、气孔直径、染色体数目上都有变化。DNA指纹图谱等方面都发生了显著的改变。多倍体齿瓣石斛试管苗出现了植株粗壮、叶片增厚等优良性状。此研究是多倍体育种技术在我国热带兰花育种中的一次成功尝试。     

基于nrDNA ITS 序列数据的兰属系统发育关系的初步分析

现存的兰属分类系统是基于宏观形态学性状、尤其是花粉块的数目以及唇瓣与蕊柱的愈合程度而建立的.兰属因此而划分为3个亚属:兰亚属 (subgenus Cymbidium),大花亚属(subgenus Cyperorchis) 和建兰亚属 (subgenus Jensoa).本文运用PCR扩增和直接测序的方法分析兰属 (Cymbidium) 27种、3个栽培品种以及3个外类群的核DNA ITS 区段序列.通过最简约性分析产生的ITS系统发育树表明,兰属的3个亚属均可能为不自然的类群.大花亚属表现为一复系群,兰亚属的冬凤兰 (C.dayanum) 隐藏于其中;建兰亚属为一并系群,它的成员之一兔耳兰 (C.lancifolium) 偏离出去而成为兰属一最基部的分支;兰亚属为一复系群,它分为几支而分别与另两个亚属组合在一起.由于兰属ITS序列位点变异率较低,最简约性分析产生的几支主要分支均得不到Bootstrap分析的高度支持,各亚属内组之间的关系也不明确.研究兰属的系统发育关系还需要新的数据.     

Allozyme Diversity in Populations of Cymbidium goeringii (Orchidaceae)

Abstract: Using 14 allozyme loci, we investigated levels of genetic diversity within populations, and degree of genetic divergence among 24 populations of Cymbidium goeringii (Orchidaceae) in Korea and Japan. Cymbidium goeringii maintains high levels of genetic diversity both at population (mean expected heterozygosity, H _e = 0.238) and species levels (0.260). Means of H _e found in 24 populations were not significantly different from each other. About 90 % of the total variation in the species is common to all populations (mean G _ST = 0.108). No unique allele was found in any population. The indirect estimate of gene flow based on the mean G _ST was high ( Nm = 2.06). Nei's genetic identities for pairs of populations had high values (mean = 0.974 [SD = 0.013]). The Mantel-Z test showed a significant correlation between genetic distance and geographic distance. However, the mean G _ST value between 17 populations in Korea and seven Japanese populations was relatively low (0.029), even though the land connection between the southern Korean peninsula and southern Japanese archipelagos has not existed since the middle Pleistocene. Large numbers of small seeds of C. goeringii might travel long distances by wind from populations to populations both in Korea and Japan, increasing genetic diversity within populations and maintaining low genetic differentiation among populations.     

A Rudimentary labellar speculum in Cymbidium lowianum (Rchb.f.) Rchb.f. and Cymbidium devonianum Paxton (Orchidaceae)

BACKGROUND AND AIMS: The labellar 'hairs' of some Cymbidium spp. are said to be thin-walled and to contain 'plasma', oil and sugars and it has long been speculated that they may function as food-hairs. However, the present authors' preliminary studies showed that certain atypical papillae may have a different role and, by reflecting light, function as a speculum. The purpose of the paper is to test this hypothesis. METHODS: Light microscopy, scanning electron microscopy, transmission electron microscopy, histochemistry and ultraviolet photography were used to investigate the structure, food content and light-reflecting properties of these papillae. KEY RESULTS AND CONCLUSIONS: The labellum of Cymbidium lowianum (Rchb.f.) Rchb.f. is densely clothed with obconical to conical papillae with wide bases and pointed tips. However, on either side of the median axis of the lip occur silvery patches comprising papillae with truncated tips and it is thought that these reflect light and thereby attract insect pollinators. Similar patches are also found in Cymbidium devonianum Paxton, and in both species, they are set against a reddish background, which, since bees cannot perceive this colour, probably appears dark to the insect thus enhancing the visual impact of the light-reflecting patches. In Cymbidium tigrinum Parish ex Hook. and Cymbidium mastersii Griff. ex Lindl., however, the labellum is mainly white and no light-reflecting patches were observed. Instead, unlike C. lowianum and C. devonianum, these species are highly fragrant and the attraction of insects probably depends to a greater extent on olfactory cues. In C. lowianum both types of papillae contain protein, starch and lipid bodies but only protein is seemingly present at elevated concentrations. However, lipoidal material also occurs upon the surface of the labellum and it is possible that this may be gathered by insects as reported for C. iridifolium A. Cunn (syn. C. madidum Lindl.). The labellar papillae of C. lowianum, thus, have the potential to function as food-hairs, although direct evidence for this is lacking.     

夏凤兰——云南兰科一新种

对兰科新种夏凤兰Cymbidium aestivum Z．J．Liu et S．C．Chen作了描述与绘图。此新种与冬凤兰Cymbidium dayanum Rchb．f．相近,但花大,萼片长4．2～4．8cm;萼片与花瓣呈淡紫褐色;花苞片披针形,长1～1．5cm;唇瓣中裂片长度约为其全长的3／5,故甚易区别于冬凤兰。     

<Emphasis Type="Italic">In vitro</Emphasis> plant regeneration from the immature seeds of <Emphasis Type="Italic">Cymbidium faberi</Emphasis>

An in vitro plant regeneration protocol of Cymbidium faberi from immature seeds was established. The immature seeds of 50 days old started to form rhizomes 4 months after they were cultured on hormone free medium. The rhizomes multiplied 5 times when subcultured on the medium containing 1.0 mg l^–1 -naphthalene acetic acid (NAA) for 40 days and more than 90% of the rhizomes initiated shoots within 60 days on the media containing 0.5 or 1.0 mg l^–1 NAA plus 2.0 or 5.0 mg l^–1N⁶-benzylaminopurine (BA). Plantlets were regenerated when the shoots were planted on the basal medium amended with 1 g l^–1 activated charcoal for 50 days and the plantlets grew normally after transplanting.     

大花蕙兰组培快繁技术研究

选用大花蕙兰杂交新品种1053为外植体,采用1/2MS为基本培养基进行大花蕙兰组培快繁技术研究,结果表明：类原球茎诱导的最佳外植体为大花蕙兰鳞茎,培养基最佳激素浓度配比为0.5 mg/L 6-BA＋0.2 mg/L NAA;类原球茎增殖与分化芽最佳激素浓度配比为1.0 mg/L 6-BA＋0.3 mg/L NAA;幼芽增殖的最佳激素浓度配比为2.0 mg/L 6-BA＋0.5 mg/L NAA,最佳有机添加物为150 ml/L椰汁,幼芽增殖正交试验得出影响因素主次顺序：6-BA〉椰汁添加物〉NAA,优组合为2 mg/L 6-BA、0.5 mg/L NAA、添加物椰汁150 ml/L;诱导生根的最佳激素浓度配比为0.3 mg/L IBA＋0.2 mg/L NAA,添加香蕉泥100 g/L对幼苗根生长有显著的促进作用。优化后的大花蕙兰组培快繁技术参数,可为大规模工厂化生产提供参考。     

江西主要山脉春兰野生居群遗传结构与分化

利用ISSR分子标记对江西省主要山脉的21个春兰(Cymbidium goeringii(Rchb.f.)Rchb.f.)居群进行居群遗传结构研究。结果显示,利用14个筛选的引物共扩增出139条条带,其中多态性条带118条,多态性条带百分率(PPL)为84.89%。21个居群的Nei s基因多样性(He)为0.2292,Shannon指数(I)为0.3613。AMOVA分析表明,春兰居群间变异占50.79%,居群内变异占49.21%,居群间的遗传分化大于居群内的分化。STRUCTURE群体遗传结构和UPGMA聚类分析均表明,江西主要山脉的春兰居群存在地理隔离和生境片断化。推测江西春兰曾广泛分布于罗霄山脉和武夷山脉,受第四纪冰期影响,春兰群体因气候剧烈变化而骤减,仅在山脉间适宜的环境中得以保存并繁衍至今,罗霄山脉和武夷山脉是春兰最主要的两个冰期避难所。综合遗传多样性与居群遗传结构特点,建议在遗传多样性较高的石城(SC)、宜丰(YF)、贵溪(GX)居群设点进行就地保护;对资源破坏严重的大余(DY)和井冈山(JGS)居群实行迁地保护。     

墨兰多舌奇花MADS特异表达基因筛选及分析

以墨兰‘南菊’为代表,用抑制消减杂交和基因芯片相结合技术构建墨兰多舌与正格花舌间的差异表达基因文库,筛选与花形态建成相关的MADS差异表达基因并构建系统进化树。结果表明:在多舌瓣中筛选出32个上调表达MADS基因,包括TM6、AG、AP1、DEF1、AP3及PI基因。其中有10个基因与AGL17、AGL29、FUI聚为一类,12个基因与其他的MADS基因归为一类。这些MADS基因参与了多舌瓣发生,并可能扮演了重要角色。该研究可为从兰花多舌变化的角度阐明墨兰奇花形成的分子机理及培育中国兰花新奇优良品种提供思路和理论依据。     

濒危莲瓣兰杂交育种及原生地种子萌发的研究

以莲瓣兰'大雪素'(Cymbidium tortisepalum 'Daxuesu')和'剑阳蝶'(Cymbidium tortisepalum 'Jianyangdie')为亲本,研究莲瓣兰种间杂交育种、杂交种子在原生地播种共生萌发及植株形态发生过程,为莲瓣兰杂交育种新品种选育及杂交种子原生地播种种苗快速繁殖奠定基础.结果表明,莲瓣兰种间杂交结实率在90.0%～93.3%之间,杂交亲和性较强;莲瓣兰杂交种子在原生地播种6～12月后,能被萌发菌侵染、种胚突破种皮形成类原球茎,种子在原生地播种容易萌发;类原球茎转绿成根状茎、根状茎伸长成丛生型根状茎、丛生型根状茎顶端分生组织分化出原球茎、原球茎分化出叶和根、根状茎逐渐退化完成植株再生过程极其缓慢,需要4～6年的时间.