In Vitro Organogenesis

植物细胞和组织在适当条件下去分化并产生芽和根的能力形成了现代植物生物技术的基础。顶端分生组织的形成是产生新的有功能的芽和根的关键。 顶端分生组织负责植物初生体的组织和器官的形成-植物中所有细胞的母亲。 虽然最近的进展已经在理解顶端分生组织的形成和功能在正常的植物发育，我们仍然没有完全了解分生组织的形成，导致根和芽的发展，从体外环境。这项研究计划的总体目标是提供一个在体外分生组织和器官形成的机制的理解。我们设计了新的协议，芽再生拟南芥合子胚在手杖阶段和根尖为外植体。我们的协议不同于传统的程序中，芽诱导培养基含有脱落酸（阿坝）。 这导致形成绿色的器官发生愈伤组织，从该愈伤组织将持续地发育芽。 这种器官发生愈伤组织的精确鉴定使我们能够详细研究芽形成的过程。此外，我们使用拟南芥，使我们能够利用许多可用的转化系和定义的抗体，研究发展过程的细节与信心。拟开展的研究的目的是：（1）研究器官发生愈伤组织的个体发生和表征负责芽形成的器官发生细胞，（2）研究与芽形成相关的结构和分子事件，（3）研究芽器官发生过程中激素分布和水平的变化，（4）探讨阿坝在再生过程中的作用方式。正如Ian Sussex教授在他的评论（Cell 56：225，1989）中所述，“分生组织构成植物”。 没有功能性分生组织的形成，就不能声称在任何系统中取得了任何生物技术上的成功。所获得的结果将提供一个健全的理论理解顶端分生组织的形成和改进的设计方案的生物技术。

The ability of plant cells and tissues to de-differentiate and give rise to shoots and roots under appropriate conditions forms the basis of modern day plant biotechnology. The key event in the generation of new functional shoots and roots is the formation of apical meristems. Apical meristems are responsible for tissue and organ formation of the primary plant body - the mother of all cells in plants. Although recent advances have been made in understanding apical meristem formation and function during normal plant development, we still do not fully understand meristem formation leading to root and shoot development from an in vitro environment. The overall goal of this research program is to provide a mechanistic understanding of in vitro meristem and organ formation. We have devised new protocols for shoot regeneration by using Arabidopsis zygotic embryos at the walking-stick stage and root tips as explants. Our protocol differs from the conventional procedure in that the shoot induction medium contains abscisic acid (ABA). This results in the formation of a green organogenic callus wherefrom shoots will consistently develop. This precise identification of the organogenic callus allows us to study the process of shoot formation in detail. Moreover, our use of Arabidopsis allows us to take advantage of the many available transformed lines and defined antibodies to study details of the developmental processes with confidence. The objectives of the proposed research are (1) to study the ontogeny of the organogenic callus and to characterize the organogenic cells that are responsible for shoot formation, (2) to study the structural and molecular events associated with shoot formation, (3) to study changes in the distribution and levels of hormones during the course of shoot organogenesis, and (4) to study the mode of action of ABA in the regeneration process. As Professor Ian Sussex stated in his review (Cell 56: 225, 1989) "The meristems make the plant". Without the formation of functional meristems, one cannot claim to have any biotechnological success in any system. The results obtained will provide a sound theoretical understanding of apical meristem formation and improved designs of protocols for biotechnology.