爱玉子花的变异类型及其相关统计分析

该文报道了爱玉子（Ficusawkeotsang）花序中存在变异花的现象,并通过花序解剖观测及数据统计分析方法,研究比较雌、雄花序中变异花的类型、不同品系的花序变异率以及单花序中变异花的数量,了解变异花发育过程、变异花与传粉小蜂之间的相互关系,以及变异花对爱玉子产量造成的影响。结果表明：爱玉子变异花在形态上有单生与伞形花序状2种类型,雌花序中的变异花分布在雌花区和退化花区：雄花序中的变异花均生长在瘿花区。雌花序中伞形花序状的A型变异花影响传粉小蜂对正常雌花的授粉,与正常雌花争夺养分和生长空间从而影响正常雌花的生长发育,大量A型变异花的存在使未授粉的雌花序延迟凋落或挂树不落,造成养分流失。雌性品系太和6、太7、W13、乐野8、日野20和大洋Z106的花序中A型变异花数量较多,对产量有一定的影响。除A型外的其它类型的变异花,由于数量少且结构简单,或发育后熟,对传粉小蜂的传粉、产卵以及花序的发育、成熟没有显著影响。无论是雌性品系还是雄性品系,以扦插苗繁殖方式形成的植株,其花序变异率高于以实生苗繁殖方式形成的植株。以上研究结果为高产优质爱玉子品系的选育提供了一定的依据,且对于爱玉子的栽培和推广有着重要的指导意义。     

爱玉子花发育的形态学研究

通过花序标记、形态解剖及放蜂实验方法,观察不同发育时期爱玉子雌、雄花序中花的形态特征,以及花发育与小蜂传粉(或产卵)之间的相关性。结果表明,雌前期、雌花期的瘿花在形态上没有明显变化,而雌花的花柱与柱头连成长鞭状,在雌前期呈直立管状,进入雌花期后呈弯曲的S形;在榕小蜂进入花序传粉或产卵5 d后,雌花和瘿花的柱头变黄,花柱开始脱水;在榕小蜂传粉或产卵10 d后,雌花和瘿花花梗伸长,花明显分层,胚迅速发育,子房饱满,花柱和柱头明显萎蔫。传粉小蜂在花序腔内的存活时长不超过3 d。本研究为揭示榕-蜂共生机制提供科学依据。     

爱玉及其传粉昆虫的共生关系

爱玉是榕属攀援灌木,其隐头花序中生活着薜荔榕小蜂,爱玉一年两次开花,雌雄株比1：2,雌花序中平均有5503朵雌花。雄花序中平均有6308朵瘿花,自然状态上结实率和成虫瘿率分别为83.52%,51.33%。薜荔榕小蜂一年两代,1只雌蜂进入花序平均可产约600个卵或使1391朵雌花受粉结实,爱玉依赖薜荔榕小蜂传粉,否则不能结实;薜荔榕小蜂是惟一能进入花序的传粉者并依靠爱玉花序得以栖息,二者在形态结构。生理功能上高度互适,生活史上完全吻合衔接。生态策略上紧密协调,构成复杂而又精细的共生体系。     

薜荔和爱玉及其传粉昆虫繁殖特性

薜荔(Ficus pumila L．var．pumila)隶属桑科榕属,爱玉(F．pumila L．var．awkeotsanmg Corner)为其变种,它们的花是单性的,雌雄异株。雌花序中着生雌花,雄花序中有瘿花和雄花,每个花序中花的数量极多,达4000～6000朵。薜荔榕小蜂是唯一能进入薜荔和爱玉的隐头花序中产卵或传粉的共生昆虫,自然状态下雌花的结实率分别为82％、83．52％;瘿花的成虫瘿率分别为58．71％、51．32％,因此可形成大量的果实和虫瘿。物候观察表明薜荔和爱玉花期不遇,它们花序中的榕小蜂种群已经生殖隔离。人为的放蜂实验表明,生活于爱玉花序中的榕小蜂,已无法在薜荔花序中繁殖,生殖隔离进一步得到证实;实验同时表明爱玉的花粉亦不能使薜荔雌花结实,宿主两变种间生理上已不亲和。本文从共生双方协同进化的角度出发,探讨了榕树2变种间与传粉昆虫繁殖特性的差异,以及变种产生的主要原因。     

爱玉子不同品系农艺性状的评价与优良品系的筛选

采用模糊数学方法,以生长势、攀爬力、抗病力、叶面积、花和花序性状、落果数、果胶含量、果胶酯酶活性、苞口胶液量及净蜂程度等性状为指标,对福建省栽培的爱玉子(Ficus awkeotsang Makino)雌性及雄性品系进行综合评价, 在此基础上,筛选出适宜在福建省推广栽培的优良品系.结果显示,根据雌性品系的12个性状进行综合评价后,可将供试的24个爱玉子雌性品系分为3类,其中大洋T84、新25、红9及W13等4个品系为第1类,综合性状最好;大洋T84和新25品系具有单果较小但结实率高、花序香气浓郁、成熟期较早、果熟期较为整齐和果胶含量高等性状,红9和W13品系具有果型较大、成熟期稍晚、果实品质较好、果胶含量和果胶酯酶活性均较高等性状,这4个品系均可作为主栽品系;而归于第2类和第3类的部分品系虽然不适宜作为主栽品系,但具有一些优良的单项性状,可作为优良育种材料.根据雄性品系的11个性状进行综合评价后,可将16个雄性品系分为3类,其中第1类包括早熟的大洋74品系、中熟的大洋23和大洋225品系以及晚熟的浙江M1和浙江M2品系,均为优良品系,评判值均在0.8以上.将早熟、中熟和晚熟的爱玉子雄性品系与优良的雌性品系共同配植可提高授粉率和坐果率,从而提高爱玉子的产量.     

爱玉子上幼期爱玉子榕小蜂与虫瘿的协同发育

[目的]特种果树爱玉子Ficus pumila var.awkeotsang依赖榕小蜂传粉方能结实.本研究旨在了解爱玉子榕小蜂Wiebesia sp.nr.pumilae及其虫瘿发育动态,为榕小蜂发育生物学研究奠定基础.[方法]通过人工放蜂-标记-定期采样-显微镜和电镜观测的方法,观察爱玉子榕小蜂-虫瘿协同发育过程以及...     

鸭梨及其变异类型的RAPD分析

鸭梨为梨属白梨系统优良资源,生产中其变异类型较多。本文首次对鸭梨及其9个鸭梨变异类型进行RAPD分析,并初步筛选出3个多态性引物即S28、S32、S176。研究发现:芽变品种垂枝鸭梨增加了1条特异带(S32-600)。在芽变品种魏县巨鸭梨、甜鸭梨、垂枝鸭梨的扩增产物中均少1条特异带(S28-400)。魏县巨鸭梨扩增产物中缺少2条特异性条带(S176-900和S176-1150)和阎庄自花结实鸭梨缺少1条特异性条带(S176-1150)。可见魏县巨鸭梨、甜鸭梨、垂枝鸭梨与阎庄自花与其他类型能区分开。     

五福花科花部形态的变异式样及其系统学意义

由于四福花Ｔｅｔｒａｄｏｘａ顶花、侧花均为典型的４数花,并被认为是科内最原始的属,因而长期以来关于五福花Ａｄｏｘａ“总苞一萼”还是“萼一花冠”的争议得到了彻底解决。根据本研究,五福花顶花和侧花的变异痃较五福花科另外３个分类群要高得多。五福花顶花和侧花的变异率分别为２０％和３６１％。通过后位雄蕊的退化和两则相邻花瓣的融合,雄蕊和花瓣从６数至３数的减少系列仅存在于五福花中。本文假设五福花科顶花和侧花的     

基于28S, COI和Cytb基因序列的薜荔和爱玉子传粉小蜂分子遗传关系研究

薜荔和爱玉子均属于桑科榕属植物,二者为同一物种的原变种与变种的关系,早期研究认为这两种榕树与同一种传粉榕小蜂(Wiebesia pumilae (Hill))建立了稳定的互利共生关系,但近期在形态学、生态学、传粉生物学等方面对二者的研究结果表明,薜荔传粉小蜂和爱玉子传粉小蜂之间可能发生了遗传分化。实验用核糖体28SrDNAD1-D3区、线粒体Cytb及COI基因部分序列,对采自福建3个不同样地的薜荔传粉小蜂和3个不同品系的栽培爱玉子的传粉小蜂进行分析,结果表明:(1)薜荔传粉小蜂和爱玉子传粉小蜂的核糖体28S序列的碱基组成中A,T,G,C 4种含量较平均,C+G的平均含量(56%)稍高于A+T的含量(44%)。线粒体Cytb序列中A+T的含量(76.1%)明显高于C+G的含量(23.9%),COI序列中A+T的含量(71.9%)也明显高于G+C的含量(28.1%),这是膜翅目昆虫线粒体基因的普遍特征。在薜荔和爱玉子传粉小蜂的线粒体Cytb及COI基因中,密码子第三位点A+T的含量最高。(2)比较薜荔和爱玉子传粉小蜂的3种分子标记的变异范围显示,28S进化速度较Cytb及COI序列慢,比较保守,更适合科、亚科等较高分类单元的研究。薜荔传粉小蜂与爱玉子传粉小蜂之间的亲缘关系较近,采用Cytb与COI序列进行分析更为精确。(3)用Cytb及COI序列对薜荔传粉小蜂与爱玉子传粉小蜂之间的遗传距离进行分析显示,薜荔传粉榕小蜂个体间Cytb序列平均遗传距离为0.0054,爱玉子传粉小蜂个体间的Cytb遗传距离为0.0164;薜荔传粉小蜂与爱玉子传粉小蜂群体之间的Cytb序列平均遗传距离为0.1385;COI序列的薜荔传粉榕小蜂个体间遗传距离为0.0048,爱玉子传粉小蜂各样本间平均遗传距离为0.0102;薜荔传粉小蜂与爱玉子传粉小蜂群体间COI序列平均遗传距离为0.1896,两群体间的遗传距离(差异大于10%以上)明显大于群体内各样本之间的遗传距离,表明薜荔传粉小蜂与爱玉子传粉小蜂之间已经发生了很大的遗传分化,其变异水平达到了种间分化水平,即薜荔传粉小蜂与爱玉子传粉小蜂为两个不同的种。     

滇蜀豹子花核型及其变异研究

本文详细报道了滇蜀豹子花的核型,发现居群中存在两种细胞型,即A型和B型。A型参考核型为2n = 24＝2m(2SAT)+2sm+8st(4SAT)+12t(2SAT),其第3号两条同源染色体长臂均无居间随体：B型参考核型为2n=24＝2m(2SAT)+2sm+8st(2SAT)+12t(3SAT)+0—1b,其第3号一条同源染色体长臂紧靠着丝点处有一大而明显的居间随体,而另一条同源染色体则无,构成明显的3号染色体的结构杂合性。统计表明,居群中二者的比例近似为1A;2B。研究还发现了大量的体细胞染色体结构变异核型,表明滇蜀豹子花核型尚未趋于稳定,还处于强烈分化之中,高频率的体细胞染色体结构变异是其种内分化不可忽视的一种进化要素。     

Purification and Characterization of Pectinmethylesterase from Ficus awkeotsang Makino Achenes

Pectinmethylesterase from the pericarp of jelly fig (Ficus awkeotsang) achenes was extracted and purified to a specific activity of 289 micromole proton produced per minute per milligram protein. Pectinmethylesterase, a major protein with high specific activity in the crude extract, was monomeric with a molecular weight of 38,000. The enzyme preparation was stable in distilled water at 4°C for at least 6 months, and at 60°C for at least 10 minutes. This enzyme functioned optimally at pH 6.5 to 7.5 when the assay mixture contained no NaCl or at low NaCl concentration. The pH optimum shifted to lower pH as the NaCl concentration was increased. The K_m value for pectin was 0.75 milligram per milliliter pectin, corresponding to a V_max value of 310 micromoles per minute per milligram protein. Inhibition studies with antibodies indicated that jelly fig achene pectinmethylesterase and the two other pectinmethylesterases from orange and tomato were similar in their active site conformation; however, the surface determinants may be very different because no precipitation between anti-jelly fig pectinmethylesterase immune serum and the pectin methylesterase from orange and tomato could be observed in the double immunodiffusion analysis. Specific antisera raised against jelly fig achene pectinmethylesterase in a Western blot experiment also showed low similarity between jelly fig pectinmethylesterase with that from orange and tomato. This observation was also supported by the very low isoelectric point (pH 3.5) of jelly fig pectinmethylesterase, compared with high isoelectric points reported for most of the pectinmethylesterases. Amino acid composition and N-terminal sequence have been obtained. High homology of the N-terminal amino acid residues between jelly fig and tomato pectinmethylesterase (O Markovic, H Jornvall [1986] Eur J Biochem 158: 455-462) was observed. Pectinmethylesterase activity causes the release of protons from the deesterification of pectin such that a low pH environment is created, and this may be related to the cell growth. Pectinmethylesterase is not needed for jelly fig seed germination, however the gel formed from pectin and pectinmethylesterase may insure a water source for the germinating jelly fig seeds.     

爱玉子（Ficus awkeotsang）不同品系的繁殖生态学比较

对不同品系爱玉子（Ficus awkeotsang）的繁殖系统进行了研究。推算表明：爱玉子栽培的雌、雄株数量配植比例可以从目前的4～5：1提高到23—24：1,以使传粉小蜂种群达到合理密度,提高结实率和成虫瘿率,增加单位面积雌株的栽培数量,提高爱玉子单位面积产量,增加土地栽培效益。比较爱玉子不同品系雌、雄花序的B期（雌花期）与雄花序的D期（雄花期）花序数量变化及持续时间,结果表明：栽培爱玉子雄花序D期时长约1个月,而雌、雄花序的B期时长却是2～3个月,B、D期不能完全重叠,导致B期花序因没有小蜂传粉（或产卵）而脱落。因此建议对雄株的B期花序进行人工引蜂的方法修复小蜂种群,从而延长雄性品系D期时长;而雌、雄品系配植模式应为1：2～4,即1个雌株品系与2—4个D期依次衔接的雄株品系配植。福建省的爱玉子栽培急需引进和选育D期早熟和晚熟的雄性品系。     

栽培爱玉的传粉生态

栽培爱玉传粉生态的研究表明,栽培爱玉开花期明显分为春、秋两季,持续时间均较野生爱玉长.爱玉不能依靠生长于原变种薜荔花序中的小蜂授粉或产卵,在野生爱玉传粉小蜂隔离的情况下,小蜂缺失造成传粉系统损毁.栽培爱玉可通过人工引入传粉小蜂建立新种群,但传粉系统修复比较缓慢,历经4年花序挂树率仅达51.11%、挂树花序的平均结果率为64.37%,平均成虫瘿率为64.35%.花序发育的雌花期和雄花期重叠度低、小蜂出飞过于集中、进入花序的小蜂数量少或缺失是造成共生双方繁殖率低下的原因.     

Cloning and immunolocalization of an antifungal chitinase in jelly fig (Ficus awkeotsang) achenes

A 30-kDa protein extracted from the pericarpial portion of jelly fig (Ficus awkeotsang Makino) achenes has been identified as a thermostable chitinase based on its enzymatic activity. A cDNA fragment encoding the precursor protein (including a cleavable signal sequence) of this chitinase was obtained by PCR cloning, and subsequently confirmed by immunological recognition of its overexpressed protein in Escherichia coli. Homology modeling predicted that this thermostable chitinase in jelly fig achenes comprised a stable (betaalpha)(8) barrel fold with three pairs of disulfide linkage. Immunostaining indicated that this chitinase was exclusively localized in the pericarpial region but not in the seed cells where bulky protein bodies and massive oil bodies were accumulated. Spore germination of Colletotrichum gloeosporioides, a common post-harvest pathogen infecting ripening fruit of jelly fig and many other fruits, was inhibited by this chitinase purified from achenes. It is suggested that the biological function of the thermostable chitinase in the pericarp of jelly fig achenes is to protect the nutritive seeds from fungal attack during fruit ripening.     

Purification and characterization of an antifungal chitinase in jelly fig (Ficus awkeotsang) achenes

A method was developed to purify a 30-kDa protein from jelly fig (Ficus awkeotsang) pericarp, including preparation of jelly curd from achenes, extraction of proteins from the curd, and isolation of the 30-kDa protein by anion-exchanger and gel filtration. Chitinase activity was detected in the purified 30-kDa protein by activity staining in both non-denaturing gel electrophoresis and SDS-PAGE. Isoelectrofocusing showed that the isoelectric point of the 30-kDa protein was lower than pH 3.5. The K(m), k(cat), optimal pH and temperature of this putative chitinase were determined to be 0.076 mM, 0.089 s(-1), pH 4, and 60 degrees C, respectively. The purified 30-kDa protein was thermostable (retaining activity up to 65 degrees C for several hours) and could be stored at 4 degrees C for a year without apparent loss of chitinase activity. Antifungal activity of this putative chitinase was measured in terms of inhibition of Colletotrichum gloeosporioides spore germination.     

Induction of Pectinmethylesterase in the Pericarp of Achenes of the Jelly-Fig Ficus awkeotsang Makino

Induction of pectinmethylesterase (PME) activity in the pericarpof achenes can be achieved by opening the syconium of the jelly-fig(Ficus awkeotsang Makino) and exposing the achenes to air. Amongseveral factors examined, exposure to the atmosphere is thecritical factor for the induction of the synthesis of PME inachenes obtained from green, pollinated syconia at differentdevelopmental stages. A close relationship between the rapidincrease in pectinmethylesterase activity and a rapid increasein protein content was observed in the achenes that were removedfrom the syconium and air-dried for several hours. The proteincontent and enzymatic activity reached a plateau value in onlytwenty-four hours. The dramatic increase in enzymatic activityis due to protein synthesis de novo rather than the activationof a pre-existing precursor of PME. (Received November 1, 1989; Accepted March 22, 1990)     

湖榕和小叶榕花形态结构特征的研究

通过对湖榕（Ｆｉｃｕｓ　ｓｐ．）和小叶榕（Ｆｉｃｕｓ　ｍｉｃｒｏｃａｒｐａ　Ｌ．）花形态结构特征的比较研究表明：湖榕和小叶榕的花果形态结构有较显著的差别。湖榕雌花的萼片数多为４片,萼片顶部都有毛,花粉位为精园形,花粉壁较薄,其结实率较低,只有０．１％;小叶榕雌花的萼片数多为３片,萼片顶部光滑无毛,花粉粒为圆形而壁较厚,其结实率较高,为２９．１％。