大花蕙兰与兰属植物种间杂交研究

进行了大花蕙兰、墨兰、建兰、纹瓣兰、兔耳兰等兰属植物的种间远缘杂交实验.在52个杂交组合中,86.5%的杂交组合具明显的子房膨大和果荚发育,但授粉4个月后未变黄落果的杂交果仅占组合数32.7%,经胚胎培养获得植株的杂交组合只占组合数的19.2%.大花蕙兰×墨兰与墨兰×大花蕙兰的杂交成功率有较大的差异.     

大花蕙兰与墨兰杂交结实率研究初报

取3个大花蕙兰品种与1个墨兰品种进行自交与杂交。共设计10个组合,成功获得4个杂交组合;共授粉257朵花,成功获得21个果荚,结实率为8.1%。大花蕙兰与墨兰杂交正反交的结实率差异不大。各组合果荚生长曲线走势大致相同,授粉后10~12 d,子房开始膨大,并于60~80 d趋于平稳。大部分落果于授粉后30d内发生,部分于生长中后期黄化脱落,双亲遗传物质的不协调性及栽培管理可能是重要影响因素。     

大花蕙兰与墨兰种间杂交子房培养研究初报

大花蕙兰与墨兰种间远缘杂交是培育具香味、易开花、早开花、抗性强的大花蕙兰品种的有效途径之一。本研究以大花蕙兰为母本,墨兰为父本进行种间杂交,共设计三个杂交组合。结果显示,同一组合子房不同离体时间培养萌发率差异明显,且不同组合间最适宜子房培养的离体时间有所差异。三个杂交组合最适宜的子房离体时间分别为授粉后90 d、120 d及100 d,萌发率分别为80.0%、80.0%及60.0%。     

兰属植物种间杂交亲和性研究

以10个中国兰品种和8个大花蕙兰品种为材料开展了兰属植物间的杂交试验,比较不同组合的杂交亲和性。结果表明:(1)54个杂交组合,共授粉582朵,获得杂交果实131个,平均结实率为22.51%;中国兰与大花蕙兰正交结实率(23.19%)高于反交结实率(9.27%)。(2)墨兰与大花蕙兰无论正交或反交均可获得较高的结实率,其亲和性高于春兰、建兰与大花蕙兰杂交的亲和性。(3)中国兰种间杂交亲和性较高,3类组合结实率均大于30%,但不同品种间杂交亲和性不一,春兰‘绿萼’,墨兰‘企黑’、‘白墨’,建兰‘金荷’,大花蕙兰‘黄金岁月’比较适宜做母本;春兰‘大富贵’,墨兰‘富贵’、‘白墨’,大花蕙兰‘月影’、‘日本绿’和‘黑珍珠’比较适宜做父本。     

大花蕙兰组织培养技术研究

以大花蕙兰Cymbidium hybridum侧芽为外植体,以N6、B5、CC、MS为基本培养基,设计无机大量元素、无机微量元素、有机物三因素四水平正交试验,探究大花蕙兰丛生芽增殖的最佳基本培养基、生长调节剂浓度配比以及诱导生根的最佳生长调节剂浓度。结果显示,大花蕙兰丛生芽增殖的最佳培养基组合为B5无机大量元素+ CC无机微量元素+MS有机物+蔗糖30 g·L-1 +琼脂7 g·L-1 +活性炭0.5 g·L-1(pH 5.8～6.0),诱导丛生芽增殖的适宜生长调节剂浓度配比为6-BA 4.0 mg·L-1 + NAA 0.2 mg·L-1,诱导生根的最佳生长调节剂浓度为NAA 1.0 mg·L-1。     

大花蕙兰营养器官及原球茎的解剖学研究

对大花蕙兰试管苗营养器官及原球茎的解剖学研究结果表明：根由复表皮、皮层和维管柱组成,根毛丰富,皮层发达,内皮层明显,初生木质部月多元型,中央具髓,根茎由表皮,基本组织和维管束构成,维管束散生,属周木型;叶为等面叶,在上下表皮处分布有成束的厚壁组织,叶肉无栅栏组织和海绵组织之分,细胞排列紧密,维管束鞘由机械组织构成。原球茎原生分生组织的原套仅一层细胞,在顶端分生组织后面的薄壁细胞中,存在胚性细胞,由胚性细胞经球状胚可发育成幼原球茎。     

大花蕙兰高频再生体系的研究

以大花蕙兰无菌苗假球茎为材料诱导丛生芽。适宜诱导的培养基为MS 6.4g·L~(-1)琼脂 0.5%活性炭 2.0mg·L~(-1)6- BA 0.1mg·L~(-1)NAA 30g·L~(-1)蔗糖。其芽长至2～3cm时,转入生根培养基,适宜的生根培养基为MS 6.4g·L~(-1)琼脂 0.2mg·L~(-1)6-BA 0.5mg·L~(-1)NAA 0.5mg·L~(-1)生根粉(ABT),生根率为100%。根长2～4cm时炼苗移栽,成活率可达95%。     

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。     

大花蕙兰类原球茎形态发生的组织学研究

以大花蕙兰类原球茎发生发育不同阶段的培养物为试材,采用石蜡切片法对其进行组织学研究。结果表明,类原球茎形成过程中,表层薄壁细胞首先经脱分化恢复分生能力,形成愈伤组织,随后在其表面形成瘤状突起--类原球茎;类原球茎继续发育,在其周围形成多个不规则突起,并进一步发育形成新的类原球茎;而原来的类原球茎开始进入器官分化阶段,逐渐形成完整的小植株。根据观察,类原球茎起源可能存在两条途径:体细胞胚胎发生和器官发生。     

建兰与纹瓣兰种间杂种胚培养研究

采用人工授粉的方法,以‘小桃红’建兰为母本、纹瓣兰为父本进行杂交,获得了种间远缘杂交后代植株。杂交果苹与母本自交果荚的大小差异大小,但鲜重明显大于母本,果荚内的种子量却少于母本。杂种胚离体培养90d出现绿色原球胚,210d可萌发出大量植株;而‘小桃红’自交种子培养210d只形成少量绿色根状茎。杂种胚的萌发具有杂种优势,不仅萌发快,而且出苗率高,萌发时先形成原球胚,原球胚上长出大量小根毛,继而形成大量假鳞茎,假鳞茎经转瓶培养后,分化形成大量健壮植株,分化率高。     

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.     

六种国产兰属植物的核型研究

首次研究了6种国产兰届植物的染色体形态和核型。果香兰(Cymbidium suavissimum)核型为2n＝40＝30m 10sm;碧玉兰(C．lowianum)为2n=40=26m 12sm 2st;文山红柱兰(C．wenshanense)为2n＝40=28m 10sm 2st;虎头兰(C．hookerianum)为2n＝40＝30m 8sm 2st;独占春(C．eburneum)为2n＝40＝36m 4sm莎草兰(C.elegans)为2n＝40＝28m 8sm 4st。结合形态学特征和已有的核型资料,对兰属植物的核型进化进行了初步的讨论。     

Relatedness Among Rhizobium and Agrobacterium Species Determined by Three Methods of Nucleic Acid Hybridization

Deoxyribonucleic acid (DNA) was isolated from 20 strains of Rhizobium and Agrobacterium and from one strain of Serratia marcescens; the guanine plus cytosine content of each DNA sample was determined by thermal denaturation. Radioactive DNA was isolated from three reference strains following the uptake of [2-(14)C]thymidine in the presence of deoxyadenosine. Ribonucleic acid (RNA) polymerase was used to synthesize radioactive RNA on DNA templates from the three reference strains. Radioactive DNA and RNA from the three reference strains were each hybridized with filter-bound DNA from all of the 21 test strains in 6 x SSC (standard saline citrate) and 50% formamide at 43 C for 40 hr. DNA/DNA relatedness was also determined by spectrophotometric measurement of the rates of association of single-stranded DNA. The order of relatedness between strains was similar by each method. Overall standard deviations for the DNA/DNA and DNA/RNA membrane filter techniques were +/-0.87 and +/-1.03%, respectively; that for the spectrophotometric technique was +/-4.11%. The DNA/DNA membrane technique gave higher absolute values of hybridization than did the DNA/RNA technique. R. leguminosarum and R. trifolii could not be distinguished from each other by these techniques. These results also indicated close relationships between R. lupini and R. japonicum, and (with less certainty) between R. meliloti and R. phaseoli. Of all the rhizobia tested against the A. tumefaciens 371 reference strain, the R. japonicum strains were the most unrelated. The three Agrobacterium strains used were as related to the R. lupini and R. leguminosarum references as were several rhizobium strains.     

The Cultivation of Hybrid Cotton in Vitro to Overcome the Incompatibility of Hybridization between the Species

2—3 days after cross-pollination the hybrid ovules of cotton (Gossypium hirsutum×G. arboreum) were cultivated in vitro. The hybrid zygot in excised ovule started to divide, frequently passing through several stages to develop into cotyledonous embryos. The embryos were inducted into seedlings. The hybrid plants in blossom were obtained as a result. The histological study was done for ovules of self- pollination in vivo and of cross-pollination in vitro. The early abortion of endosperm in hybrid ovules was observed. In the prophase the nucellus was disintegrated slowly, and in the middle and terminal phase it disintegrated more rapidly. These were identified in hybrid F1. The size of corolla is intermadiate form between female and male. The violet-red spots at the base of petals are similar to male, while there are no such spots in female. None of the pollen can fertilize. Hybrid F1 is not fertile after self-pollination or backcross by the pollen of parent. The chromosome number in root tip Cell of hybrid F1 is 2n=3x=39.     

Introduction to Special Issue on Primate Hybridization and Hybrid Zones

International Journal of Primatology -     

Cymbidium quinquelobum,A New Species of Orchidaceae from Yunnan

Cymbidium quinquelobum, a new orchid from Yunnan, is described and illustrated. It is akin to Cymbidium wenshanense Y. S. Wu et F. Y. Liu, from which it differs by having a 5- lobed lip that is fused at base to the basal margins of the column forming a tube 8- 10 mm long .