欧报春二型花柱的繁育特性研究

二型花柱植物通常具有自交不亲和性,在不同植物中所表现的可育性不同。欧报春(Primula vulgaris)是典型的二型花柱植物,为了探究欧报春的繁育特性,通过温室栽培,对欧报春的长花柱和短花柱的花部特征、花粉和花柱形态、花粉活力、柱头可授性、花粉/胚珠比、杂交指数、杂交亲和性、花粉管观察进行研究。结果表明,(1)长花柱和短花柱的花冠直径、花冠筒长度、柱头高度、花药高度和花筒中部直径均表现出两型性;(2)花粉和柱头观察发现花粉极轴长、花粉赤道轴长、花柱直径、柱头乳突细胞和花粉数量均有差异;(3)长花柱的花粉/胚珠比为384.20,短花柱为369.70,属于兼性异交类型;长花柱和短花柱的花粉活力和柱头可授性能在较长时间内维持较高活力;(4)长花柱杂交指数值为5,短花柱为4,表明繁育系统类型为异交,部分自交亲和,需要传粉者;6种授粉组合均能结实,异型花间授粉的结实数明显高于同型自花授粉和异株同型授粉;短花柱为母本的异型花间授粉组合亲和性优于其他组合;欧报春存在自交不亲和性,长花柱的自交不亲和性低于短花柱。     

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。     

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。     

芥菜型油菜与白菜正反杂交的胚胎学研究

利用荧光技术对芥菜型油菜(Brassica juncea)与白菜(B. pekinesis)种间正反杂交后花粉萌发和花粉管生长过程进行了观察。结果显示: 芥菜型油菜与白菜正交授粉后, 花粉在柱头上能正常萌发, 多数花粉管沿花柱到达胚珠完成受精, 且受精方式有珠孔受精、合点受精和中部受精, 少量花粉管生长不正常, 出现花粉管顶端膨大扭曲, 花粉管分支等异常现象; 反交授粉后, 花粉在柱头上萌发时柱头乳突细胞产生强烈胼胝质反应, 影响花粉管生长, 只有少量花粉管通过花柱到达胚珠完成受精。用石蜡切片技术观察了正反杂交后杂种的胚胎发育, 正交杂种胚胎发育较早, 胚和胚乳生长较正常, 杂种胚一般均能发育至成熟; 反交杂种胚发育至心型期便不能继续发育, 胚乳也停滞在游离核阶段并最终败育。综合分析 表明, 芥菜型油菜与白菜正反杂交都存在一定程度的受精不亲和性。     

芥菜型油菜与白菜正反杂交的胚胎学研究

利用荧光技术对芥菜型油菜（Brassica juncea）与白菜（B．pekinesis）种间正反杂交后花粉萌发和花粉管生长过程进行了观察。结果显示：芥菜型油菜与白菜正交授粉后,花粉在柱头上能正常萌发,多数花粉管沿花柱到达胚珠完成受精,且受精方式有珠孔受精、合点受精和中部受精,少量花粉管生长不正常,出现花粉管顶端膨大扭曲,花粉管分支等异常现象;反交授粉后,花粉在柱头上萌发时柱头乳突细胞产生强烈胼胝质反应,影响花粉管生长,只有少量花粉管通过花柱到达胚珠完成受精。用石蜡切片技术观察了正反杂交后杂种的胚胎发育,正交杂种胚胎发育较早,胚和胚乳生长较正常,杂种胚一般均能发育至成熟;反交杂种胚发育至心型期便不能继续发育,胚乳也停滞在游离核阶段并最终败育。综合分析表明,芥菜型油菜与白菜正反杂交都存在一定程度的受精不亲和性。     

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。     

猕猴桃花粉原位生长过程中Ca2+的超微细胞化学定位

应用扫描电镜和荧光显微镜对软枣猕猴桃同种花粉在柱头上原位萌发及花粉管生长情况进行了观察,并用焦锑酸盐沉淀法对其授粉前后柱头及花柱中Ca2+进行超微细胞化学定位.结果显示:(1)猕猴桃柱头属于干性柱头,具有一道裂沟,乳突呈长圆柱形,授粉前后形态差异不明显.(2)授粉后3 h,花粉管生长穿过柱头表面,授粉后7 h,花粉管生长到达花柱底部;(3)授粉前后,柱头接受面靠近柱头外围细胞的角质层一侧细胞器内含有丰富的钙,而柱头非接受表面钙颗粒分布很少;(4)授粉前和授粉后3 h,花柱顶端钙颗粒较少,基部钙颗粒较多;授粉后7 h,花柱顶端和基部钙分布密度无明显差别;(5)授粉前后花柱顶端钙主要均匀分布在细胞质膜位置;在花柱基部授粉前钙主要分布在引导组织胞间隙中,授粉后3 h主要分布在细胞质内,授粉后7 h主要存在于细胞质、内质网上.研究表明,猕猴桃授粉前后,柱头和花柱组织中均含有钙,授粉前和授粉后3 h花柱中的钙呈现出梯度分布,授粉后7 h钙的梯度分布现象减弱甚至消失.     

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。     

‘川早枇杷’头花柱头可授性及花粉活力与花粉管生长的研究

为揭示特早熟枇杷新品系‘川早枇杷’头花坐果率低的原因,该试验采用田间调查方法观察了‘川早枇杷’头花的开花期,并用联苯胺-过氧化氢法检验了柱头可授性、TTC法测定了花粉活力、苯胺蓝染色法观察了花粉管生长情况。结果显示:(1)‘川早枇杷’头花7月中旬进入初花期,7月下旬至8月上旬为盛花期,8月中旬至下旬为终花期,头花花期的果园气温最高、最低和平均分别为34.9℃、18.9℃和26.03℃。(2)开花当天及花后1~4d柱头具有可授性,且花后1d柱头可授性最强、花粉活力最高,以后花粉活力逐渐迅速降低。(3)自花授粉的花粉管在授粉后48h抵达花柱基部、96h到达胚珠,但数量极少。研究表明,‘川早枇杷’头花具有最佳可授性的时间较短,花粉活力降低迅速,花粉管能够抵达花柱基部和进入胚珠的数量极少,花期高温等诸多因素的综合作用可能是造成其头花坐果不良的重要原因。     

野菊与菊花杂交中花粉活力和柱头可授性及胚胎发育研究

应用石蜡制片、活体压片、光学显微镜及扫描电子显微镜观察等方法,研究了四倍体河南云台山野菊(Dendranthema indicum)与栽培菊花'钟山金山'(D.grandiflorum 'Zhongshanjinshan')种间杂交中父本花粉活力、花粉在柱头萌发、花粉管生长及胚胎发育情况等.结果发现,父本云台山野菊的花粉活力在授粉时为12%左右.人工授粉后的不同时间,在柱头上都观察到正常萌发的花粉粒,且花粉管都能进入柱头,其中,在授粉后0.5 h时,平均每柱头有5.9粒花粉萌发;12 h时,为59.9粒;而24和48 h时,则分别降为47.1和35.7粒.此外,在授粉后8、10、12和15 d时,分别在49.1%、40.8%、39.7%和38.5%子房内观察到正常发育的胚胎,最终杂交结实率为44.8%,而母本自然开放结实率为52.3%.研究表明,授粉前其多数母本雌蕊发育良好、授粉后多数花粉能在柱头正常萌发和花粉管正常生长,在受精后大部分胚胎发育正常是野菊与栽培菊种间杂交较高结实率的重要保证,而授粉前父本较低的花粉活力对杂交结实率影响不大.     

Pollen Tube Growth and Seed Set of Banksia coccinea R.Br. (Proteaceae)

Controlled hand pollinations and field observations were usedin conjunction with fluorescence and scanning electron microscopyand fruit and seed set to investigate the timing of stigma receptivity,pollen tube growth and self-incompatibility in relation to fertilityin B. coccinea. The species showed both protandry and partialself-incompatibility. Peak stigma receptivity as measured bypollen germination was recorded at 3 d after anthesis and maximumproduction of stigmatic exudate at 6 d. Pollen tubes reachedthe base of the style by 6 d after pollination. A 5 x 5 diallelexperiment was conducted and the results measured by pollentube growth. Self-pollinations generally resulted in poorertube growth than crosses and there was significant specificand general combining ability as well as reciprocal effects.Cross-pollination resulted in improved fruit set and seed toflower ratio over both selfing and open pollination. Spatiallimitations to fertility due to infructescence size were alsorecorded, but the combination of outcrossing mechanisms andspatial limitation did not entirely account for the low fertility.It is suggested that environmental conditions and the availabilityof resources may also exert an influence. Banksia coccinea R.Br., scarlet banksia, Proteaceae, pollination, stigma receptivity, pollen tube growth, self-incompatibility, breeding system, seed set     

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.     

外来入侵植物意大利苍耳的传粉生态学特性

从开花物候、花粉活力、柱头可受性、传粉媒介、花粉散布距离、雄性、雌性功能以及繁育系统等方面系统地研究了意大利苍耳的传粉生态学特性,旨在为揭示该物种成功入侵的机理提供科学依据。研究结果显示:意大利苍耳种群的花期较长,雌花花期可达40d,雄花花期可达30d。其雄性和雌性功能都很强,意大利苍耳单株雄花序和花粉量分别高达3847个/株和37903037粒/株,单株雌花序和单株胚珠数高达3847个/株和7694枚/株,种群平均结实率高达80.59%,即平均每株个体能形成6200枚成熟的果实。花粉活力的日变化呈单峰型曲线,早晨和傍晚的花粉活力最低,14:00时的活力高达99%。雌蕊柱头一经伸出总苞即具有可受性,可受期长达7d,开花后的3—4d柱头的可受性最强。意大利苍耳为风媒传粉植物,在4.5km/h的微风条件下,其花粉的散布距离可达45m,大量的花粉集中分布在距花粉源0—20m的范围内,这对于往往高密度连片分布的意大利苍耳种群来说无疑是一种高效的传粉策略。意大利苍耳的交配系统灵活多样,盛花期自然结实率达到100%,套袋试验结果表明该植物自交亲和,自株自然授粉的结实率高达93%。表明较长的花期、大量的雌雄花序及花粉数量、较高的花粉活力、较长的柱头可授期、较远的花粉风媒散布距离、混合交配系统、以及较高的结实率是意大利苍耳繁殖成功的重要保障,也是其成功入侵的重要原因。     

Semi in vivo pollen tube growth of Aechmea fasciata

With semi in vivo pollen tube growth assays, stigmas are pollinated in vivo and, after a fixed time interval, the styles are isolated from the ovary and placed on culture medium in vitro. Semi in vitro pollination includes isolation of the stigma and style complex, followed by pollination and placing the stylar end on nutrient medium. After semi in vivo pollination more and longer pollen tubes protruded from the cut end of the styles into medium, in comparison to semi in vitro pollination. Medium with 3 g l^–1 agar was better than that with 6 g l^–1 agar for pollen tube growth after the tubes emerged from the cut style. Semi in vitro pollination of the reversed style indicated that pollen tube growth was not influenced by the direction of the style. Fructose and glucose inhibited pollen tube growth compared to sucrose. Swollen tips characterized tube growth inhibition. After semi in vivo pollination all generative nuclei had divided to give two sperm nuclei. The average distance between the last sperm nucleus and the pollen tube tip as well as the distance between the two sperm nuclei diminished in growing pollen tubes between 24 and 48 h after pollination. The arrangements between the vegetative and the generative nuclei did not differ in semi in vivo and in vitro cultured pollen tubes of Aechmea fasciata. This information is important to explain why fertilization rate is low after placental pollination in comparison to placental grafted style pollination of Aechmea fasciata. The data may also contribute to the improvement of in vitro fertilization methods in Bromeliaceae and other higher plants.     

Gametophyte–Sporophyte Interactions in the Pollen–Pistil System: 3. Hormonal Status at the Progamic Phase of Fertilization

The content of hormones, IAA, ABA, and cytokinins, as well as the rate of ethylene production in petunia (Petunia hybrida L.) pistils and their parts (stigma, style, and ovary) were determined over 8 h after compatible pollination. At the progamic phase of fertilization in the pollen–pistil system, the phytohormones were virtually absent from the ovary but were present in various proportions in stigma and style. The stigma was the main site of ethylene synthesis and contained 90% of ABA while the style contained 80% of cytokinins of their contents in the whole pollinated pistil. Stigma and style did not differ in their IAA levels. The interaction of the male gametophyte with the stigmatic tissues was accompanied by a threefold increase in the ethylene production and a 1.5-fold increase in the IAA content in the pollen–pistil system within 0–4 h. Growth of pollen tubes in the stylar tissues (4–8 h) was accompanied by a further increase in IAA content and a decrease in the ethylene production by stigmatic tissues, as well as by a decrease in the cytokinin content in the stylar tissues. The ethylene/auxin status of the stigma may be suggested to control the processes of adhesion, hydration, and germination of pollen grains during pollination, while the auxin/cytokinin status of the style controls the pollen tube growth.     

Pistil Receptivity and Pollen Tube Growth in Relation to the Breeding System of Eucalyptus woodwardii (Symphyomyrtus: Myrtaceae)

Pistil structure, stigma receptivity and pollen tube growthwere investigated in relation to seed set of Eucalyptus woodwardii.Self-pollination resulted in reduced capsule retention and seeddevelopment as compared with cross-pollination. The pistil consistedof an ovary with five locules, a long style with a canal extendingfor two-thirds of its length, and a papillate stigma. Therewas no change in style length with time after anthesis, butboth stigma secretion and ability to support pollen germinationand tube growth increased to reach a peak at 7 d. Pollen germinatedon the stigma surface and in the stylar canal, but most tubegrowth occurred intercellularly in the transmitting tissue surroundingthe canal. At the base of the style the pollen tubes split intofive groups following the transmitting tissue strands to theovary. Each group grew through a septum dividing two loculesand entered the placenta. The tubes then emerged from the placentato penetrate the ovules at between 10 and 20 d after pollination.Fewer ovules were penetrated following self- than cross-pollination. Eucalyptus woodwardii Maiden, Lemon-flowered gum, Pistil receptivity, Pollen tube growth, Breeding system, Self-incompatibility     

Hormonal status of the pollen-pistil system at the progamic phase of fertilization after compatible and incompatible pollination in Petunia hybrida L.

The hormonal status of the pollen-pistil system in Petunia hybrida L. during the progamic phase of fertilization was investigated. The contents of indolyl-3-acetic acid (IAA), abscisic acid (ABA), and cytokinins, as well as the rate of ethylene production in the pistils and their parts (stigma, style, and ovary) were measured over an 8-h period following compatible and self-incompatible pollination. In both pollinations, the phytohormones were present in various proportions in the stigma, style and ovary: the stigma was the main site of ethylene synthesis and contained 90% of the ABA, while the style contained 80% of the total cytokinin content in the pollinated pistil. Relatively low levels of hormones in the ovary did not influence the hormonal status of the pollen-pistil system. The interaction of the male gametophyte with the stigmatic tissues was accompanied by a 7- to 10-fold increase in ethylene production and a 1.5- to 2.0-fold increase in IAA content in the pollen-pistil system over 0–4 h. Pollen tube growth after self-incompatible pollination, in contrast to compatible pollination, was accompanied by a 3-fold increase in the ABA content in the stigma and style and by a 5-fold higher cytokinin content in the stylar tissues. Thus, the ethylene/ABA status of the stigma may play a role in controlling the processes of adhesion, hydration, and germination of pollen grains during pollination while the auxin/cytokinin status of the style may be involved in controlling pollen tube growth.     

Gametophyte–Sporophyte Interactions in the Pollen–Pistil System: 4. The Hormonal Status and the Mechanism of Self-Incompatibility

Following 4 and 8 h after self-incompatible pollination of Petunia hybrida plants, ethylene evolution and the contents of IAA, ABA, and cytokinins were measured in pistils and their parts (stigma, style, and ovary). The germination and initial growth of pollen tubes within the initial 4 h of the experiment were accompanied with an almost tenfold increase of the rate of ethylene production by the stigma and a twofold increase of the ABA content in the stigma and style. The inhibition of pollen tube growth in the style tissues during next 4 h coincided with a fivefold increase in the cytokinin content in the style, while high ABA content was maintained in the stigma and style. The authors conclude that phytohormones participate in the mechanism of gametophyte self-incompatibility.