激光扫描共聚焦显微镜观察水稻双受精过程

利用激光扫描共聚焦显微镜对水稻双受精过程进行了观察。结果表明:开花后0.5 h可见花粉粒在柱头上萌发,形成一定长度的花粉管,但仍未进入胚囊;开花后1~2 h花粉管进入胚囊,但尚未释放精细胞,此时,在卵器内有两条肌动蛋白冠的形成,肌动蛋白冠起始于助细胞的基部,1条终止于卵细胞核的位置,另一条终止于极核附近;开花后2~3 h花粉管释放精细胞,精细胞在肌动蛋白冠的作用下分别进入极核及卵细胞;开花后3~4 h,精核的染色质向卵核扩散,极核内的雄性核仁逐渐变大,最后增大至与极核的核仁差不多大小;开花后4~5 h,精核与极核完成受精作用,形成初生胚乳核,而此时在卵核内出现1个雄性核仁;开花后6 h左右,卵核核仁仍未完成与精核核仁的融合,此时初生胚乳核已分裂1~2次;开花后12 h,精核核仁与卵核核仁融合形成1个较大的核仁,至此合子形成;开花后24 h,合子有丝分裂1次,形成2个细胞的原胚,此时初生胚乳核已分裂形成8~16个游离核,绕胚囊周缘分布。水稻双受精作用属于有丝分裂前配子融合类型。     

矮生菜豆胚珠和胚囊的发育

本文观察了矮生菜豆（Ｐｈａｓｅｏｌｕｓｖｕｌｇａｒｉｓｖａｒ．ｈｕｍｉｌｉｓ）胚珠和胚囊的发育。通常大孢子母细胞减数分裂形成三个直线排列的细胞，合点端大孢子具功能，功能大孢子发育成蓼形胚囊。成熟胚囊中，三个反足细胞已消失。两助细胞分别在受精前后退化。两极核受精前融合或不融合。卵细胞的细胞质中有少量淀粉粒。珠孔端及合点端的胚囊壁均具发达的壁内突。成熟胚珠为弯生型、双珠被、厚珠心。四核胚囊形成后，淀粉粒依次出现在珠被组织，珠心组织及中央细胞中，至开花前２～３天达到高峰。开花前一天，珠心和中央细胞中淀粉粒开始减少。     

丹参大孢子发生和雌配子体发育

利用石蜡切片法对丹参不同时期花器官进行了解剖学研究。结果表明:丹参单珠被,薄珠心,倒生胚珠,有承珠盘结构。孢原细胞位于珠心一层表皮下,直接行使大孢子母细胞功能。大孢子母细胞减数分裂合点端或合点端第二个大孢子为功能大孢子,胚囊发育为蓼型。胚囊中卵细胞存在极性。助细胞在卵细胞产生极性分化前解体,即助细胞寿命较短。反足细胞在成熟胚囊中退化。极核在受精前融合,核中出现多个小核仁。     

The FERONIA receptor-like kinase mediates male-female interactions during pollen tube reception

In flowering plants, signaling between the male pollen tube and the synergid cells of the female gametophyte is required for fertilization. In the Arabidopsis thaliana mutant feronia (fer), fertilization is impaired; the pollen tube fails to arrest and thus continues to grow inside the female gametophyte. FER encodes a synergid-expressed, plasma membrane-localized receptor-like kinase. We found that the FER protein accumulates asymmetrically in the synergid membrane at the filiform apparatus. Interspecific crosses using pollen from Arabidopsis lyrata and Cardamine flexuosa on A. thaliana stigmas resulted in a fer-like phenotype that correlates with sequence divergence in the extracellular domain of FER. Our findings show that the female control of pollen tube reception is based on a FER-dependent signaling pathway, which may play a role in reproductive isolation barriers.     

Micropylar pollen tube guidance by egg apparatus 1 of maize

Pollen tube guidance precedes the double fertilization of flowering plants. Here, we report the identification of a small maize protein of 94 amino acids involved in short-range signaling required for pollen tube attraction by the female gametophyte. ZmEA1 is exclusively expressed in the egg apparatus, consisting of the egg cell and two synergids. Chimeric ZmEA1 fused to green fluorescent protein (ZmEA1:GFP) was first visible within the filiform apparatus and later was localized to nucellar cell walls below the micropylar opening of the ovule. Transgenic down-regulation of the ZmEA1 gene led to ovule sterility caused by loss of close-range pollen tube guidance to the micropyle.     

女贞的胚胎学及其在木犀科中的系统地位

 应用光学显微镜对女贞的传粉和受精、胚乳和胚胎的发育、果皮和种皮的发育等胚胎学特征进行了研究,对木犀科六属的胚胎学特征进行了比较.虫媒传粉,珠孔受精,花粉管通过一助细胞进入胚囊;初生胚乳核先于合子分裂,核型胚乳发育;胚胎发育属茄型,种子具丰富的油质胚乳和匙形稍弯的双子叶的胚;果皮分3层:外果皮细胞厚壁,中果皮细胞薄壁,内果皮细胞厚壁且木栓化;种皮也分3层.胚胎学特征显示女贞属与茉莉属有较近的亲缘关系,支持木犀科分成3亚科的分类.     

Anatomical Study on the Multi-Ovule Development and Abortion of Hanfu Apple

The terminal flower buds of 6-yr-old Hanfu apple were used to study the ovule development, ovular characteristics, cell death of abortive ovules, and dynamic change of starch grain quantity in the embryo sac with paraffin slices and terminal deoxynucleotidyl transferase-mediated fluorescein deoxyuridine triphosphate nick-end labeling （TUNEL） system. Four anatropous ovules in each ventricle could be observed before flowering. With the developing of floral organ, the bulk of normal ovules enlarged in each ventricle, the mature embryo sac differentiated into nucellus, and the egg cell developed into zygote by double fertilization. A large number of starch grains were observed during pollen tube growth and double fertilization, which guaranteed basic nutrient supply in the normal development of ovules. Moreover, abortion phenomenon of runtish ovules emerged at the stages of mature embryo sac, double fertilization and zygote development. The abortion characteristics included deformity of ovule development, degradation of nucellus tissue, separation between funiculus and ovule, abnormality of four-nucleate embryo sac, as well as development interruption of mature embryo sac. TUNEL analysis proved that ovule abortion was programmed cell death.     

樟科檫木的大孢子发生和雌配子体发育

采用常规石蜡切片技术对檫木的大孢子发生和雌配子体的发育过程进行了观察。结果表明:檫木单子房,子房卵形,光滑无毛;具1枚胚珠,双珠被,厚珠心;大孢子母细胞由1个雌性孢原细胞直接发育而成,大孢子四分体呈线型;蓼型胚囊,成熟胚囊为8核,包括1个卵细胞、2个助细胞、一个含2核的中央极核和3个反足细胞。檫木的雌配子体很少出现数目齐全的胚囊核,且珠心组织有解离现象,推测这影响了雌配子体的正常发育,导致胚囊败育和结实率低。     

“十里香”茶大小孢子发生发育的细胞学研究

 本文报道了"十里香"茶大小孢子发生和雌雄配子体的形成过程。"十里香"茶花粉母细胞减数分裂为"同时型",四分体为"田"字形或四面体形,其外胼胝质壁的形成和溶解都是向心的。雄配子体形成和发育过程中其核的形态和位置变化均具有规律性。中轴胎座,倒生胚珠,双珠被,薄珠心,胚囊属双胞型胚囊,其发育类型为"葱"型。二极核在受精前融合,反足细胞宿存至受精,合点端具承珠盘。     

海南油茶授粉后雌蕊内源激素的动态变化

为了研究内源激素与海南油茶自交不亲和性的关系,利用酶联免疫检测法,研究了海南‘青果油茶’(Camellia vietnamensis)和‘糙果油茶’(Camellia furfuracea)授粉过程雌蕊内源激素(赤霉素GA₃、吲哚乙酸IAA、脱落酸ABA、玉米素核苷ZR)含量的动态变化规律。结果表明：花粉管进入胚囊后,IAA的水平降低,抑制了后期花粉管的生长,较低水平的GA₃也抑制了花粉管的生长;当花粉管进入胚囊后,高水平的GA₃抑制了花粉管的生长和配子体的释放,但高水平的ZR能促进花粉管在柱头中的正常生长,同时高水平的ABA也能促进花粉管的生长和受精;内源激素的比例失调也是海南油茶的自交不亲和性的影响因素。     

Pollen-stigma interaction and cross-incompatibility in the grasses

The failure of interspecific and intergeneric crosses in the grasses is commonly due to zygotic inviability, embryo abortion, or endosperm abnormalities, all of which occur after fertilization. Often, however, there is difficulty in obtaining fertilization because the pollen tube fails to reach the embryo sac. This article concerns recent research on pollen-stigma interaction in the grasses and the light it is beginning to throw on prefertilization self- and cross-incompatibilities.     

巴旦杏雌蕊形态及早期胚胎发生的研究

①巴旦杏雌蕊形态结构为：湿型柱头,花柱实心,子房１室,基生胎座,横生胚珠,双珠被,厚珠心,有珠孔塞。②巴旦杏存在明显的雌雄蕊异熟现象：花粉授粉后２ｈ左右便可萌发,而雌蕊胚囊在开花时仍处在４核期。观察的材料中,绝大部分胚囊在授粉第３天逐渐进入８核早期,第９天发育为成熟胚囊,胚囊为蓼型。③珠孔授精,花粉管最早在授粉第９天进入珠孔,第１０～１１天进入胚囊完成双受精。胚乳在授粉第１１天后出现,受精卵休眠１～２ｄ于授粉第１２天前后进行第一次分裂,胚胎发生为紫菀型。此外,本研究还对巴旦杏早期胚胎发生中胚珠的多糖和单宁物质动态进行了观察。     

水稻多胚苗的初步研究 Ⅰ.胚胎学的观察

对3份水稻多胚材料的胚囊观察表明,水稻多胚来源有5条途径:(1)合子胚原体裂生形成2个胚;(2)合子与助细胞受精同时发育成胚;(3)反足细胞多次分裂形成类似胚状的“拟胚”;(4)珠心细胞进入胚囊发育形成胚原体;(5)胚乳发育形成胚状体.其中第(1),(2)条途径能形成多胚苗.由反足细胞形成的‘拟胚”一般只能发育到几十个细胞就停止了.珠心细胞形成的胚原体,由于发育时间较迟,只有合子胚败育后,才能得到进一步的发育.     

草莓胚和胚乳发育的研究

以哈尔滨地区推广的“戈雪拉”和“小实”草莓品种为材料,采用常规石蜡切片法,荧光技术和透射电镜技术,对草莓受精、胚和胚乳的发育过程进行观察,其结果如下：１．草莓属于多心皮离生单雌蕊,柱头较小,表面有栅状排列的乳突细胞,花柱细长,中央可见有较发达的引导组织,子房内１枚横生胚珠,单珠被,厚珠心,蓼型胚囊,利用荧光法可清楚看到落在柱头上的花粉萌发,花粉管的延伸途径,即由柱头一花柱引导组织—子房内壁—胎座—胚珠表面—进入珠孔。２．胚的发育过程与大多数双子叶植物基本一致,先后经历了合子—二细胞原胚—球形原胚—心形胚—鱼雷形胚—成熟胚等阶段,胚发育属紫菀型,胚的形态呈直立型。３．草莓属核型胚乳,先后经历初生胚乳核—胚乳游离核—胚乳细胞—胚乳逐渐被胚吸收等过程,戈雪拉品种幼胚发育中,在其周围具有一个特殊的结构     

龙须草成熟胚囊结构和类型的观察

采用常规石蜡切片法,观察了龙须草成熟胚囊的结构和类型。结果表明,龙须草的成熟胚囊通常;是由靠近珠孔的１个４核胚囊分化而来;发育类型为体细胞无孢子生殖的大黍型;成熟胚囊由１个卵细胞,２个助细胞和含１个极核的中央细胞组成。     

龙须草成熟胚囊结构和类型的观察

采用常规石蜡切片法, 观察了龙须草成熟胚囊的结构和类型。结果表明龙须 草的成熟胚囊通常是由靠近珠孔端的1个4核胚囊分化而来;发育类型为体细胞无孢子生殖的大黍型;成熟胚囊由1个卵细胞、2个助细胞和含1个极核的中央细胞组成。     

太和樱桃胚胎发育的研究

研究了太和樱桃大鹰紫甘桃品种雌雄配子体、授粉受精和胚的发育阶段及时间。结果表明,３月初花粉粒发育成熟,３月１３日开花时胚囊发育成熟,授粉后２６ｈ花粉管进入子房,然后进行双受精作用,形成初生胚乳核和合子。至４月初合子发育成原胚,原胚经分裂与分化,形成幼胚,４月中旬胚发育完全。胚胎发育与樱桃结果关系密切,树体营养和外界气候条件对胚胎发育过程有重要影响。     

葡萄双受精过程的形态学观察

观察了葡萄双受精过程中雌雄性核的融合。结果表明:花粉管通过珠孔穿入退化助细胞,释放出二精子;精子核接近并贴附在卵核和次生核上,二者核膜融合,精核沉入卵核及次生核,染色质松解,并与雌性核染色质融合,出现雄性核仁,两性核仁融合,形成合子及初生胚乳核。卵核完成受精较次生核晚。受精属有丝分裂前型。精核进入卵核前看到了它的核仁。少数胚囊具有两套卵器。     

K型小麦雄性不育系诱导单倍体胚的胚胎学观察

从胚胎学方面研究了粘果山羊草细胞质的小麦雄性不育系K83(21)35A与保持系83(21)35B杂交的双受精过程,胚和胚乳的发育特点,以及单倍体胚和孪生胚发生的规律。结果表明:双受精过程、胚和胚乳的发育与普通小麦自交相似。n型单倍体胚来自助细胞的孤雌生殖;n-n型双胚来自助细胞和卵细胞的孤雌生殖;2n-n型双胚中的单倍体胚来自助细胞,二倍体胚来自受精卵。适当延迟授粉,能提高单倍体发生的频率。