小报春不同授粉组合亲和性研究

利用小报春‘红星’、‘紫霞’、‘罗兰香’3个品种分别设置8种授粉组合,统计了不同授粉组合的结实情况和单果种子数量,并对‘红星’品种部分授粉组合的花粉萌发与花粉管伸长过程进行荧光显微观察。结果显示:(1)3个品种的结实率和单果种子数量均表现为异型植株授粉>长花柱同型异株授粉、长花柱自交>短花柱同型异株授粉、短花柱自交,不同授粉组合间单果种子数量差异极显著,异型植株授粉类型结实率均达到100%,单果种子数量为44～181粒,显著高于自交组合和同型异株杂交组合;以异型致死花粉作为蒙导对短花柱同型异株授粉组合的结实有一定促进作用,但对长花柱同型异株授粉组合的结实没有一致的促进作用;3个品种中‘红星’的结实率和单果种子数量最高。(2)荧光显微观察表明,异型授粉组合花粉在柱头上大量萌发并在花柱中伸长,授粉144h后花粉管开始进入子房;同型授粉组合授粉12h后花粉开始萌发,但直到授粉后144h花粉管还没有进入花柱;自交授粉组合授粉后144h仍无花粉萌发。实验结果说明,小报春存在明显的自交不亲和性,且短花柱类型的自交不亲和性比长花柱类型强。     

枇杷少核株系花粉管生长差异研究

以‘大五星’枇杷退化种子少核株系‘川农1号’(C1)为试材,以‘大五星’枇杷自花授粉为对照,采用荧光显微技术,对枇杷少核株系自花、异花授粉后花粉管生长情况进行观察。结果表明:(1)C1株系异花授粉后花粉能在柱头上萌发,并伸入中央花柱道,在授粉后48h左右到达花柱基部。(2)C1株系自花授粉后,花粉萌发与花粉管的伸长速度相对于异花授粉滞后,自花授粉后36h大多数花粉管到达花柱的中上部并停止生长,且伴随产生花粉管顶端形态异常、荧光异常明亮等现象,最终只有极少数花粉管能到达花柱基部。研究表明,C1株系为配子体自交不亲和,C1株系的自交不亲和性是引起其少核的重要原因之一。     

中国樱桃与甜樱桃花粉原位萌发及花粉管生长的差异

以‘垂丝’、‘东塘’(中国樱桃)和‘莫利’、‘拉宾斯’(甜樱桃)为试材,分别于自花、异花授粉后不同时间切取花柱,用FAA固定,荧光染色后压片观察。结果显示,中国樱桃和甜樱桃的自花、异花花粉均能在柱头萌发,且其花粉管在花柱中表现为“极快—慢—快—稳定”的动态变化过程。但甜樱桃花粉萌发率高于中国樱桃,异花高于自花。中国樱桃自花、异花都有花粉管到达花柱基部;甜樱桃‘莫利’ב拉宾斯’和‘拉宾斯’自交有花粉管到达花柱基部,而‘莫利’自交的花粉管在花柱中上部已停止生长。结果表明,中国樱桃表现自交亲和性,而甜樱桃除人工诱变导致自交亲和的‘拉宾斯’等品种外,表现典型的植物配子体自交不亲和性。     

梨远缘花粉原位萌发及生长特性

应用荧光标记方法对梨远缘花粉在‘丰水’和‘噢嗄二十世纪’柱头上萌发及花粉管生长特性进行观察,结果表明:(1)梨远缘花粉均能在柱头上萌发,但其萌发率不同,授粉后24 h,在‘丰水’柱头上‘红叶桃’花粉萌发率最高,达62.8%,而‘盖县大李’花粉萌发率仅为12.0%,各种远缘花粉在‘丰水’柱头萌发率均高于‘噢嗄二十世纪’柱头。(2)各种远缘花粉管在梨柱头或花柱内生长情况也有差异,‘红叶桃’等核果类花粉管在梨柱头上均表现为扭曲、盘绕等现象,不能穿过柱头;‘红星’和‘红富士’花粉管虽然有少量穿过柱头,但不能进一步在花柱内生长,表现为扭曲变形、先端膨大等不亲和性现象。因此,梨与远缘果树杂交不亲和在柱头上就已发生,这与梨自交不亲和反应发生在花柱内的现象不同。     

高温对苹果花粉在花柱内萌发和生长的影响

以‘长富2号’红富士苹果为母本,‘红星’苹果为父本,研究35℃高温对苹果花粉在花柱内萌发和生长的影响。结果表明：温度影响花粉在柱头和花柱内的萌发及生长,与对照相比,高温促进花粉在柱头表面快速萌发,并加速花粉管在花柱内的伸长生长,但是在授粉72hN,高温处理下培养的花粉管形态出现花粉管变粗、弯曲并有瘤状小结的异化现象,同时,花柱发生褐变,并产生胼胝质,最终导致花粉管不能进入胚珠完成受精。     

高山杜鹃与大喇叭杜鹃种间杂交过程的观察研究

以高山杜鹃‘Nova Zembla’为母本,大喇叭杜鹃为父本进行人工杂交授粉,利用荧光显微镜对杂交组合花粉萌发及花粉管生长过程进行观察,并统计其杂交的田间坐果率。结果显示:(1)授粉后1d花粉开始萌发形成花粉管,其萌发率在授粉后1～5d内显著增长,其后增长缓慢,到第12天萌发率最高达37.36%。(2)花粉萌发后花粉管生长速度由慢变快,授粉后2d花粉管进入花柱,7d进入子房,10d进入胚珠;实验中杂交花粉管与胚珠虽有结合,但与胚珠结合率低,授粉后12d仅7.42条花粉管进入胚珠。(3)在花粉管生长过程中,伴有大量异常现象,表现为授粉后柱头细胞、花粉管、花柱引导组织、子房组织、胚珠中的胚囊等部位依次出现胼胝质沉积反应,花粉管生长中出现的膨大、先端沉积胼胝塞而中途停止生长、螺旋扭曲、粗细不均、杂乱生长或螺旋膨大且逆向生长等异常。(4)该实验杂交的田间坐果率为零。研究表明,高山杜鹃‘Nova Zembla’与大喇叭杜鹃杂交不亲和,杂交后花粉管生长的异常行为可能是种间杂交不亲和的主要原因,且受精前障碍与受精后障碍可能同时存在。     

以32P示踪观察梨花粉管在自花与异花花柱中生长的方法

用适当比强度的32P溶液处理梨花期的花枝3d,获得^32P标记的花粉在花柱中生长过程的放射自显影图。结果表明,授粉后36h,自花授粉的花粉管只伸长到花柱全长的44．3％位置,并停止生长,而此时异花授粉的花粉管已到达花柱的基部。     

异叶苦竹花粉管生长及双受精过程

以异叶苦竹为材料,采用扫描电镜、荧光显微镜技术及传统的石蜡制片技术,解剖观察其花粉管生长途径及双受精过程。结果表明:(1)授粉后,花粉在柱头上吸水膨胀,约30 min即可萌发。(2)授粉1～2 h后花粉管可达到花粉长度的5～10倍,花粉管在柱头分支中进一步伸长,并开始伸入花柱中生长。(3)授粉后5 h,大量花粉管沿引导组织进入花柱基部与子房顶部之间的子房壁,有少量花粉管在子房壁与外珠被之间的缝隙中生长。(4)授粉后8 h,少量花粉管到达珠孔端。(5)授粉后15～18 h,精核与极核融合,形成初生胚乳核;精、卵核融合,形成合子。(6)授粉后20～30 h,仍可在花柱中见到大量呈束状的花粉管。(7)授粉后48 h,子房内的大部分花粉管出现解体,大多数花粉死亡。研究认为,精细胞到达胚珠的时间为8 h。     

梨花柱S-RNase对花粉管超微结构的影响

采用光学显微镜和透射电子显微镜研究了离体条件下不同品种梨花柱S—RNase对异花(亲和)及自花(不亲和)花粉萌发和花粉管生长及其超微结构的影响。结果表明,花柱S—RNase抑制不亲和花粉的萌发和花粉管的生长,对亲和花粉的萌发和花粉管的生长基本没有影响。花粉生长初期,亲和及不亲和花粉管超微结构相似;但培养24h以后,亲和花粉管中充满细胞质和细胞器,而不亲和花粉管中只有靠近花粉管前端有少量细胞质,细胞壁增厚,细胞壁与细胞质之间有一层胼胝质和电子透明区间隔。     

异叶苦竹花粉管生长及双受精过程（英文）

以异叶苦竹为材料,采用扫描电镜、荧光显微镜技术及传统的石蜡制片技术,解剖观察其花粉管生长途径及双受精过程。结果表明:(1)授粉后,花粉在柱头上吸水膨胀,约30min即可萌发。(2)授粉1~2h后花粉管可达到花粉长度的5~10倍,花粉管在柱头分支中进一步伸长,并开始伸入花柱中生长。(3)授粉后5h,大量花粉管沿引导组织进入花柱基部与子房顶部之间的子房壁,有少量花粉管在子房壁与外珠被之间的缝隙中生长。(4)授粉后8h,少量花粉管到达珠孔端。(5)授粉后15~18h,精核与极核融合,形成初生胚乳核;精、卵核融合,形成合子。(6)授粉后20~30h,仍可在花柱中见到大量呈束状的花粉管。(7)授粉后48h,子房内的大部分花粉管出现解体,大多数花粉死亡。研究认为,精细胞到达胚珠的时间为8h。     

荞麦亲和与不亲和授粉后柱头和花粉管中ATP酶的超微细胞化学定位

利用磷酸铅淀淀技术对荞麦（Fagopyrum esculentum Monch.)pin型植株分别进行亲和授粉和不亲和授粉后的柱头、花粉粒、花粉管进行了ATPase的超微细胞化学定位。结果表明（1）亲和授粉和不亲和授粉后0.5h,柱头细胞的ATPase活性反应水平较低或基于无酶活性;柱头表面、柱头上附着的花粉粒内ATPase活性在不亲和授粉时较低,亲和授粉时较高,花粉粒内ATPase主要定位于线粒体和精子细胞;（2）授粉后1.5h,不亲和授粉的柱头细胞及花粉管的ATPase活性均较低,花粉管停止生长,细胞质开始解体;而亲和授粉的柱头细胞及花粉管的ATPase活性均较高,ATPase主要定位于柱头细胞的质膜、胞基质以及花粉管的壁、质体的膜、高尔基体、线粒体上。根据不同时期不同部位ATPase活性的差异,我们认为荞麦发生自交不亲和时,花粉管在花柱中停止生长不仅是因此花粉管得不到花柱中的营养物质而引起的,可能也与花粉管自身物质代谢发生障碍有关。     

荞麦亲和与不亲和授粉后柱头和花粉管中ATP酶的超微细胞化学定位

利用磷酸铅沉淀技术对荞麦(Fagopyrum esculentum Month.)pin型植株分别进行亲和授粉和不亲和授粉后的柱头、花粉粒、花粉管进行了ATPase的超微细胞化学定位。结果表明(1)亲和授粉和不亲和授粉后0.5h,柱头细胞的ATPase活性反应水平较低或基本无酶活性;柱头表面、柱头上附着的花粉粒内ATPase活性在不亲和授粉时较低,亲和授粉时较高,花粉粒内ATPase主要定位于线粒体和精子细胞;(2)授粉后1.5h,不亲和授粉的柱头细胞及花粉管的ATPase活性均较低,花粉管停止生长,细胞质开始解体;而亲和授粉的柱头细胞及花粉管的ATPase活性均较高,ATPase主要定位于柱头细胞的质膜、胞基质以及花粉管的壁、质体的膜、高尔基体、线粒体上。根据不同时期不同部位ATPase活性的差异,我们认为荞麦发生自交不亲和时,花粉管在花柱中停止生长不仅是因为花粉管得不到花柱中的营养物质而引起的,可能也与花粉管自身物质代谢发生障碍有关。     

小报春与岩生报春种间杂交亲和性研究

以报春花属报春花组的小报春(Primula forbesii)和指叶报春组的岩生报春(Primula saxatilis)为亲本,对种间杂交的结实性及花粉管行为进行了观察。结果表明:小报春与岩生报春种间杂交表现为不亲和,正反交组合正常结实率为0,但正交、反交组合花粉在柱头表面的萌发和花粉管伸长过程有明显差异,小报春花粉授粉4h后可以在岩生报春柱头表面萌发,但花粉管伸长的速度明显比对照组[岩生报春(P)×岩生报春(T)、岩生报春(T)×岩生报春(P)]慢,并且花粉管生长弯曲,授粉192h后花粉管仍未到达子房;岩生报春的花粉可以在小报春柱头上正常萌发,授粉48h后花粉管到达子房;4个对照授粉组合均分别于24h(短花柱为母本)、48h(长花柱为母本)时完成受精过程。研究表明,岩生报春×小报春杂交存在受精前障碍,小报春×岩生报春杂交亲和性较好,并可通过幼胚拯救的方法获得组间杂种后代;花柱长度可能是影响种间杂交结实能力的因素之一。     

Studies on flower longevity in Digitalis

Flower lifespan was terminated by corolla abscission 5–6 days after stigma opening in the unpollinated flower. Increased pollen loads produced increased seed set and reduced flower longevity progressively to a minimum of one day after pollination with pure pollen. Weakening of the abscission zone was detectable 8 h after pollination, whilst the pollen tubes were still within the stigmatic zone, suggesting that a stimulus, moving at 4 mm h^–1 minimum, was transmitted through the style and ovary. Soon after pollination removal of the stigma prevented the pollination-induced corolla abscission. Later it was necessary to remove the stigma and upper style, and later still the whole style to delay abscission. The progressive induction of the stigma and style took place at a rate of 1.5 mm h^–1, in advance of the pollen tubes which grew at 0.75 mm h^–1. It was not possible to reproduce the pollination effects by application of indoleacetic acid (IAA) to the stigma or the style.Abbreviation IAA Indoleacetic acid     

Evidence for Stigmatic Self-incompatibility, Pollination Induced Ovule Enlargement and Transmitting Tissue Exudates in the Paleoherb, Saururus cernuus L. (Saururaceae)

Saururus cernuus, a species belonging to the primitive herbaceousangiosperm family Saururaceae, exhibits high rates of self-sterility.We investigated the structural and functional aspects of pollen-carpelinteractions following cross and self pollination to assessthe tissue specific site and timing of self-sterility and factorsimportant for successful cross pollen tube growth. Self-sterilitywas due to inhibition of self pollen germination at a dry stigma.Self pollination was associated with anomalous foot formation,reduced cell wall expansion and secretory activity of stigmaticpapillae, and callose production in stigmatic papillae. Followinggermination, cross compatible pollen tubes entered a solid coreof transmitting tissue and grew to the base of a short style.Entry of cross pollen tubes into the ovary was coincident withovule enlargement which placed the micropyle in the proximityof cross pollen tube tips. Ovule enlargement also occurred followingself pollination. Cross pollen tubes either entered an exudate-filledmicropyle directly from the style, or growth in the ovary waslocalized to the epidermis of the locule and outer integumentprior to entry into the micropyle. Prior to pollination, thetransmitting tract was void of secretions except for exudatein the micropyle. Growth of pollen tubes on the locule and integumentwas associated with exudate apparently arising from transmittingcells adjacent to growing pollen tubes. The present study providesthe first evidence in a primitive herbaceous species of stigmaticself-incompatibility (SI) in association with a dry stigma,pollination-induced signalling events affecting developmentof carpellary tissues, and micropylar exudates. Copyright 1999Annals of Botany Company SI evolution, dry stigma, exudates, pollen-carpel signalling, Saururaceae.     

Plantacyanin plays a role in reproduction in Arabidopsis

Plantacyanins belong to the phytocyanin family of blue copper proteins. In the Arabidopsis (Arabidopsis thaliana) genome, only one gene encodes plantacyanin. The T-DNA-tagged mutant is a knockdown mutant that shows no visible phenotype. We used both promoter-beta-glucuronidase transgenic plants and immunolocalization to show that Arabidopsis plantacyanin is expressed most highly in the inflorescence and, specifically, in the transmitting tract of the pistil. Protein levels show a steep gradient in expression from the stigma into the style and ovary. Overexpression plants were generated using cauliflower mosaic virus 35S, and protein levels in the pistil were examined as well as the pollination process. Seed set in these plants is highly reduced mainly due to a lack of anther dehiscence, which is caused by degeneration of the endothecium. Callose deposits occur on the pollen walls in plants that overexpress plantacyanin, and a small percentage of these pollen grains germinate in the closed anthers. When wild-type pollen was used on the overexpression stigma, seed set was still decreased compared to the control pollinations. We detected an increase in plantacyanin levels in the overexpression pistil, including the transmitting tract. Guidance of the wild-type pollen tube on the overexpression stigma is disrupted as evidenced by the growth behavior of pollen tubes after they penetrate the papillar cell. Normally, pollen tubes travel down the papilla cell and into the style. Wild-type pollen tubes on the overexpression stigma made numerous turns around the papilla cell before growing toward the style. In some rare cases, pollen tubes circled up the papilla cell away from the style and were arrested there. We propose that when plantacyanin levels in the stigma are increased, pollen tube guidance into the style is disrupted.     

PROTANDRY,INCOMPATIBILITY, AND SECONDARY POLLEN PRESENTATION IN CEPHALANTHUS OCCIDENTALS (RUBIACEAE)

Cephalanthus occidentalis L. is protandrous and presents pollen secondarily on the stigma surface. Because self-pollen is present on the stigma, the degree of selling vs. outcrossing in this species will depend on 1) the phenology of pollen presentation and stigma receptivity; 2) whether the species is self-incompatible; and 3) the rates of self vs. crossed pollen tube growth. This study describes floral morphology and phenology, self-incompatibility, and pollen tube growth rates in self- and crosspollinations of C. occidentalis. Light and scanning electron microscopy were used to study stigma morphology after flower opening, while controlled pollinations tested for incompatibility. Stigmas were unreceptive initially but became receptive by the second day after flower opening. Ninety-two percent of cross-pollinated flowers set fruit, compared to 12% fruit set in self-pollinations. Pollen tubes from selfed and out-crossed pollen initially had similar growth rates. Out-crossed pollen tubes began to grow rapidly ca. 5 hr after pollination of a receptive stigma, whereas selfed pollen tubes ceased growth or grew slowly after this time. Pollen tubes from out-crossed pollen grew the length of the style within 24 hr after pollination, while selfed pollen tubes were inhibited at the stigma-style junction. Our results indicate that C. occidentalis has selfincompatibility, in addition to protandry and secondary pollen presentation. Protandry allows removal of self-pollen from the unreceptive stigma, while self-incompatibility prevents fertilization by unremoved self-pollen.     

莴苣授粉前后柱头与花柱中钙的分布变化

莴苣柱头呈两裂片状,有接受花粉的接受面和非接受面之分。授粉前后,柱头接受面乳突细胞的细胞壁中贮存丰富的细小钙颗粒,而非接受面的表皮细胞壁中的钙颗：粒很少。在花柱组织中钙的分布具有明显特征,在同一水平上,钙主要分布在引导组织的质外体中,如细胞壁和细胞间隙中,而在引导组织外的薄壁组织中钙主要分布在的细胞内液泡和细胞壁中以及维管束导管内。在花柱不同水平上,花柱中的钙呈现出梯度分布,顶端各组织中的钙颗粒较少,基部各组织中的钙颗粒较多。授粉后1h花柱基部组织的钙颗粒增多,钙梯度分布现象增强。花柱引导组织中的钙梯度分布很可能是吸引花粉管向下生长的原因。讨论了莴苣花柱引导组织中钙梯度分布特征和花粉管在其体内生长的关系。