管状分子分化离体培养系统的建立及影响因素

Establishment and Influencing Factors of in vitro Culture System for Tracheary Elements Differentiation

管状分子是植物木质部的主要组成成分,具有复杂的形态学特征,在植物的生长发育过程中发挥重要作用。在离体培养条件下,植物细胞可以通过分化或转分化的方式形成管状分子,为此建立了百日草、拟南芥、杨树等离体培养模式系统,用于观测管状分子分化细胞形态结构特征的变化以及相关影响因子的调节作用,并取得较大的进展。研究资料表明:离体条件下不同植物细胞分化形成管状分子培养条件不同,其中植物激素、木质形成素、渗透压、Ca2+、起始细胞密度、pH等均参与管状分子的分化调控。迄今为止,百日草系统是研究管状分子分化较为成熟的系统,而杨树系统是研究管状分子分化最具前景的林木模式系统。这些模式系统的建立可为单细胞水平上研究管状分子的分化提供极好的平台,从而可在分子水平上认识细胞分化进程及其调节机制,最终达到木材改良的目的。

Tracheary elements （ TEs） are main component in the xylem that are highly specialized for transporting water and solutes up the plant during plant growth and development,and have complex morphological characteristics. The mature plant cells can be converted into TEs by processes of differentiation or transdifferentiation in an appropriate vitro system. Recently constructed of vitro culture systems for Zinnia,Arabidopsis,Populus and other species have been facilitating our observation of the morphological changes during TEs differentiation and understanding the factors that influence the differentiation process. Previous researches indicated that TEs differentiation processes vary with plant cells, and many factors such as phytohormone,xylogen,Ca2 ＋,osmotic pressure,initial cell population density,pH and so on, play great roles in regulating TEs differentiation. At present,the Zinnia vitro culture system is the relatively mature system for observing TEs differentiation while Populus system is the most promising system for woody plant. These model systems provide an excellent platform for study of TEs differentiation at single cell level,and greatly advance our understanding of TEs differentiation process and its control mechanism at the molecular level for ultimate goals of wood improvement.