An Overview: Somatic Embryogenesis Through Thin Cell Layer (TCL) Technique

Abstract

Somatic embryogenesis (SE) has been described as the most efficient pathway to obtaining plants. Somatic embryogenesis can be divided into direct and indirect embryogenesis. Direct SE occurs when embryos are started directly from explant tissues (preembryogenic cells) creating an identical clone, while indirect SE occurs from unorganized tissues (calli) which are further developed into embryos. While different explants have been tested, e.g., shoot tips, adventitious buds, leaf primordia, zygotic embryos, inflorescences, and transverse thin cell layers (TCLs) (consisting of a few cell layers, usually 0.5–2.0 mm thick). TCLs have been excised from different plant organs and successfully used as explants for SE. Thin cell layers (TCLs) can be prepared from almost any plant organ. These, when cut longitudinally, are referred to as lTCLs, and when cut transversally, are referred to as tTCLs. This article provides an overview of the concept of TCL as applied to induce SE in different plant species and remarks the factor that affecting this technique. This review will certainly revitalize this important technology so that it can be used effectively for successful mass propagation.