中国植物发育生物学若干重要领域的研究回顾

植物发育是指从种子萌发经过营养生长、开花与花器官发育、受精结果形成新一代的有序过程.每一个时期具有复杂的代谢和基因表达与调控网络.过去的数10年中我国在该领域的研究取得了许多重要的进展,特别是近10年来发育生物学已经从以往的以描述为主要特征发展到在分子水平上阐明发育控制的机理.花器官的发育研究是发育生物学研究最具突破性的领域,开花和营养器官的发育已经成为新的研究热点.本文按照植物发育的时间顺序,回顾了我国发育生物学若干重要领域的重要研究进展,并展望了基因组时代给发育生物学研究带来的新的机遇和研究平台.     

中国植物发育生物学若干重要领域的研究回顾

植物发育是指从种子萌发经过营养生长、开花与花器官发育、受精结果形成新一代的有序过程。每一个时期具有复杂的代谢和基因表达与调控网络。过去的数 10年中我国在该领域的研究取得了许多重要的进展 ,特别是近 10年来发育生物学已经从以往的以描述为主要特征发展到在分子水平上阐明发育控制的机理。花器官的发育研究是发育生物学研究最具突破性的领域 ,开花和营养器官的发育已经成为新的研究热点。本文按照植物发育的时间顺序 ,回顾了我国发育生物学若干重要领域的重要研究进展 ,并展望了基因组时代给发育生物学研究带来的新的机遇和研究平台     

Plant Development and Reproduction: Advances and Prospectives

Plant development and reproduction research has been moving very rapidly in the past 10 years due to the progress of molecular biology, the analysis of various developmental mutants, and the cloning of the genes with important function in different stages of plant development. This review focuses on apical mefistem, flower initiation and development, fertilization and embryogenesis. Recent advances and the prospects in the future are discussed.     

植物发育与生殖的研究：进展和展望

１　高等植物发育的特点随着分子生物学和遗传学的发展,发育生物学已重新成为生物学中最为活跃的研究领域之一。高等植物的发育有其一系列自身的特点。首先,植物的生长发育是一个开放系统,由种子萌发形成幼苗,在其生活史的各个阶段不断地形成新的器官。而动物在胚胎发育阶段已基本完成了器官的分化过程。第二,植物的营养生长转向生殖发育是植物生长到一定阶段后才完成的,对于多种植物这一过程受到光、温等外界环境因子的调控。第三,植物细胞在一定外界条件刺激下（包括离体培养）表现出高度的细胞全能性,即可以重新开始分裂并形成一…     

Emerging data on pollen tube growth and fertilization in flowering plants, 1990–1995

Summary Since its discovery at the end of the last century, double fertilization remains of central interest in plant reproductive biology research. Although the sequence of events leading to fertilization is well known from cytological studies, the underlying mechanisms remain to be elucidated. This now seems feasible by the diversification and refinement of recently developed technologies presented in this review. The progress made during the last five years in understanding pollen tube guidance, discharge into the embryo sac, and gametic fusion are described. Future directions are also discussed.Dedicated to Prof. Dr. Dr. h.c. Eberhard Schnepf on the occasion of his retirement     

Imaging fertilization in flowering plants, not so abominable after all

Although the discovery of double fertilization in flowering plants took place at the end of the nineteenth century little progress had been made in understanding the cellular and molecular mechanisms involved until the end of the twentieth century. After attempts to study fertilization with isolated male and female gametes, researchers turned to Arabidopsis thaliana as a model for genetic analysis and in vivo imaging. The development of confocal imaging and fluorescent proteins, coupled with new molecular insights into cell fate specification of plant gametes, allowed the development of robust markers for cells participating in double fertilization. These markers enabled the imaging of double fertilization in vivo in Arabidopsis. These studies have been coupled with the identification and molecular characterization of genes controlling fertilization in Arabidopsis. Live imaging has already provided new insights on sperm cell delivery, the equivalence of the fate of the sperm cells, gamete fusion, and re-initiation of the zygotic life. This review covers these topics and outlines many important aspects of double fertilization that remain unknown.     

植物进化发育生物学的形成与研究进展

植物进化发育生物学是最近十几年来才兴起的一门学科, 它是进化发育生物学的主要分支之一。进化发育生物学的产生经历了进化生物学与胚胎学、遗传学和发育生物学的三次大的综合, 其历史可追溯到19世纪初冯.贝尔所创立的比较胚胎学。相关研究曾沉寂了近一个世纪, 直到20世纪80年代早期, 动物中homeobox基因被发现, 90年代初花发育的 ABC模型被提出, 加之对发育相关基因研究的不断深入, 才使基因型与表型联系了起来, 进而促进了进化发育生物学的飞速发展。目前进化发育生物学已成为21世纪生命科学领域的研究热点之一。本文详细阐述了进化发育生物学产生和发展的历程, 综述了最近十几年来植物进化发育生物学的主要研究进展。文中重点介绍了与植物发育密切相关的MADS-box基因在植物各大类群中的研究现状, 讨论了植物进化发育生物学领域的研究成果对花被演化、花对称性以及叶的进化等重要问题的启示。     

植物进化发育生物学的形成与研究进展

植物进化发育生物学是最近十几年来才兴起的一门学科,它是进化发育生物学的主要分支之一。进化发育生物学的产生经历了进化生物学与胚胎学、遗传学和发育生物学的三次大的综合,其历史可追溯到19世纪初冯.贝尔所创立的比较胚胎学。相关研究曾沉寂了近一个世纪,直到20世纪80年代早期,动物中homeobox基因被发现,90年代初花发育的ABC模型被提出,加之对发育相关基因研究的不断深入,才使基因型与表型联系了起来,进而促进了进化发育生物学的飞速发展。目前进化发育生物学已成为21世纪生命科学领域的研究热点之一。本文详细阐述了进化发育生物学产生和发展的历程,综述了最近十几年来植物进化发育生物学的主要研究进展。文中重点介绍了与植物发育密切相关的MADS-box基因在植物各大类群中的研究现状,讨论了植物进化发育生物学领域的研究成果对花被演化、花对称性以及叶的进化等重要问题的启示。     

桃儿七传粉生物学特性及其在进化上的意义

对分布于云南中甸县不同居群的桃儿七进行了传粉生物学特性研究,结果如下：（１）首次发现其具有一种适应于自花授粉的传粉机制。即在花尚未开放或刚开放时,雌蕊呈直立状,而一旦花完全开放时,子房柄会发生弯曲,以致整个雌蕊靠向某一花药,从而使柱头与花药贴合实现传粉;当完成传粉后,雌蕊又重新直立,此时受精作用也随之完成。整个传粉、受精过程仅需４￣６ｈ。（２）其生殖节律快,有效率高。从孢子母细胞减数分裂开始到双受     

Double fertilization in flowering plants: 1898–2008

The present article gives a brief survey of results of studies in the area of plant embryology directly associated with the discovery made by S.G. Navashin in 1898 of double fertilization in vivo and in vitro. These studies utilized methods of electronic and fluorescence microscopy, cytophotometry, and cultures of isolated ovules, sperm, and the embryo sac central cell. Questions related to the origin of the female gametophyte of flowering plants, double fertilization, and the endosperm are considered. It is emphasized that progress in this field is associated chiefly with the study of molecular processes that regulate the development and functioning of the female gametophyte and the sporophyte on early stages of ontogenesis.     

Manipulating fertilization: a management tactic against Frankliniella occidentalis on potted chrysanthemum

Fertilization during production of greenhouse chrysanthemum, Dendranthema grandiflora (Tzvelev), will influence Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) populations as well as plant productivity and postproduction longevity. It is essential to include fertilization effects in the development of crop management practices that reduce thrips populations and maintain plant marketability. In this study, we lowered fertilization to reduce thrips population abundance while maintaining plant productivity. We tested fertilization levels below and above the recommended level (375 p.p.m. N) for commercial production. We reduced mean rate of change in F. occidentalis abundance from 0.05 to 0.03 (day⁻¹) and mean number of thrips per plant by 44% by fertilizing with either 188 p.p.m. N (50% of the recommended level) or 568 p.p.m. N (150%) and higher. Fertilization influenced not only the rate of change in thrips abundance but also the production time (from transplanting to flower opening). Lowering fertilization to 50% of the recommended level lengthened mean production time from 84 to 88 days. Plant height, flower size, and flower number were not adversely affected when fertilization was reduced to 50% of the recommended level. Mean postproduction longevity was shortened from 26 to 24 days when plants were fertilized with 50% of the recommended level. Two important advantages of lowering fertilization to 50% of the recommended level were (1) a 44% reduction in mean F. occidentalis abundance and (2) a significant reduction in fertilizer input for the production system. Manipulation of fertilization can be a useful management tactic against F. occidentalis .     

Gene networks controlling the initiation of flower development

The onset of flower formation is a key regulatory event during the life cycle of angiosperm plants, which marks the beginning of the reproductive phase of development. It has been shown that floral initiation is under tight genetic control, and deciphering the underlying molecular mechanisms has been a main area of interest in plant biology for the past two decades. Here, we provide an overview of the developmental and genetic processes that occur during floral initiation. We further review recent studies that have led to the genome-wide identification of target genes of key floral regulators and discuss how they have contributed to an in-depth understanding of the gene regulatory networks controlling early flower development. We focus especially on a master regulator of floral initiation in Arabidopsis thaliana APETALA1 (AP1), but also outline what is known about the AP1 network in other plant species and the evolutionary implications.     

OBPC Symposium: Maize 2004 &; beyond—Plant virus-based vectors in agriculture and biotechnology

Summary The study of plant viruses and their interaction with the plant host has contributed greatly to our understanding of plant biology. The recent development of plant viruses as transient expression vectors has not only enhanced our understanding of virus biology and antiviral defense mechanisms in plants, but has also led to the use of plant viral-based vectors as tools for gene discovery and production of recombinant proteins in plants for control of human and animal diseases. An overview of the state-of-the-art of viral expression systems, is presented, as well as examples from our laboratory on their use in identifying nuclear targeting motifs on viroid molecules and development of therapeutic proteins for control of animal diseases.     

Seed abortion in the sexual counterpart of <Emphasis Type="Italic">Brachiaria brizantha</Emphasis> apomicts (Poaceae)

Gametophytic organization, fertilization and reproductive success are described for the fertile diploid Brachiaria brizantha accession BRA-002747 which is being raised for use in Brachiaria breeding programs, as well as to understand and control of apomixis in this genus. The current paper reports on reproductive biology and analysis of seed set in field experiments during three consecutive years. Unsuccessful seed production in this plant is believed to correlate with early inbreeding depression, based on the reproductive features analyzed. Caryopsis development was observed using differential interference contrast microscopy with seed set determined by the number of self- and open-pollinated pistils that fully developed into viable seeds. Developing and mature female and male gametophytes were observed in the context of flower phenology, morphology and anthesis patterns. Pollen viability was determined by acetocarmine staining and by observation of germination in vivo, which was also used to observe pollen tube/pistil interaction. Although normal development was observed in floral structures, anthesis and gametophytes, seed set was low, with 2 and 6% in self- and open-pollination, respectively, producing seed. Variations observed in the female organs, such as the presence of a hermaphrodite flower in 50% of the inferior floscules and the presence of multiple embryo sacs of the Polygonum type within the same ovule in 15% of the pistils, are not related to low fertility. The majority of pollen grains are viable, in spite of the reduced number of pollen tubes within the style and ovary carpel, and a developing caryopsis was observed in 70% of self-pollinated pistils, indicating successful double fertilization from 2 days after anthesis (DAA). Nevertheless, abortion gradually increased from 2 until 7 DAA and remains elevated until 12 DAA, when caryopsis maturity is achieved. These data confirm low seed set in this accession and indicate that low fertility is not a consequence of abnormalities, either in the floral or gamete structures, or pollen tube rejection, but most likely a consequence of inbreeding depression.     

Double fertilization in flowering plants: 1898-2008

A short review of the results of investigations in the field of plant embryology in vivo and in vitro which are directly connected with the discovery of double fertilization in flowering plants by S.G. Navashin is presented. These results have been obtained by using the methods of electron and fluorescence microscopy, cytophotometry, cultures of isolated ovules, sperms, eggs, and embryo sac central cells. The question on an origin of the female gametophyte of flowering plants, double fertilization, and endosperm are discussed. It is emphasized that the progress in this field is connected mostly with the study of molecular processes which control the development and functioning of a female gametophyte and sporophyte at the early stages of ontogenesis.     

A rich and bountiful harvest: Key discoveries in plant cell biology

The field of plant cell biology has a rich history of discovery, going back to Robert Hooke’s discovery of cells themselves. The development of microscopes and preparation techniques has allowed for the visualization of subcellular structures, and the use of protein biochemistry, genetics, and molecular biology has enabled the identification of proteins and mechanisms that regulate key cellular processes. In this review, seven senior plant cell biologists reflect on the development of this research field in the past decades, including the foundational contributions that their teams have made to our rich, current insights into cell biology. Topics covered include signaling and cell morphogenesis, membrane trafficking, cytokinesis, cytoskeletal regulation, and cell wall biology. In addition, these scientists illustrate the pathways to discovery in this exciting research field.

Seven senior plant cell biologists reflect on foundational contributions to a variety of topics, including pollen tube signaling, cell morphogenesis, membrane trafficking, cytokinesis, cytoskeletal regulation, and cell wall biology.     

Comparison of transcripts in Phalaenopsis bellina and Phalaenopsis equestris (Orchidaceae) flowers to deduce monoterpene biosynthesis pathway

Background  

Floral scent is one of the important strategies for ensuring fertilization and for determining seed or fruit set. Research on plant scents has hampered mainly by the invisibility of this character, its dynamic nature, and complex mixtures of components that are present in very small quantities. Most progress in scent research, as in other areas of plant biology, has come from the use of molecular and biochemical techniques. Although volatile components have been identified in several orchid species, the biosynthetic pathways of orchid flower fragrance are far from understood. We investigated how flower fragrance was generated in certainPhalaenopsis orchids by determining the chemical components of the floral scent, identifying floral expressed-sequence-tags (ESTs), and deducing the pathways of floral scent biosynthesis inPhalaneopsis bellina by bioinformatics analysis.     

Molecular repertoire of flowering plant male germ cells

Sperm cells—the male gametes of flowering plants—constitute the male founding lineage of angiosperms, possessing the unique capacity to fuse with the egg and central cells during double fertilization. Although it is well established that these cellular fusions are involved with initiating the development of the seedling-forming zygote and the endosperm that nourishes it, considerable information will be needed to characterize the full male molecular repertoire, which includes expressed genes of the male lineage, encoded proteins, and regulatory elements controlling male germ line identity, as well as male molecules that may mediate interactions with the female partner that initiate fertilization and development. Progress is being made using increasingly sensitive molecular methods to uncover important genes. With the pace of this discovery rapidly increasing, the likely outcome is that key molecules will be discovered within the next several years that control the founding cells of the embryo and endosperm and are involved in directing early development. Further insights into the genes and gene pathways that regulate male germ line differentiation will advance not only our fundamental understanding of these reproductive cells, but also the nature of cell–cell recognition, membrane fusion, double fertilization, zygote activation, early plant development and may aid our understanding of factors that have contributed to the overwhelming evolutionary success of flowering plants.     

被子植物生殖细胞和精细胞

随着被子植物精细胞分离技术的突破和细胞生物学以及分子生物学技术的发展,对被子植物精细胞的研究不断深入。在以前细胞生物学研究的基础上结合近年来的分子生物学研究结果对被子植物雄性生殖细胞的产生、精细胞的形成和发育以及有关精细胞的表面蛋白质、精细胞的特异启动子、精细胞cDNA文库的构建等分子生物学研究进展和今后的发展趋势进行了综述。