10 - Study of plant chromosomes from tissue culture

Abstract

This chapter presents a study of plant chromosomes from tissue culture. Tissue culture technique allows the cultivation of cells, tissues, and organs in vitro in natural medium or in artificial medium, but reproducing as far as is practicable the conditions in vivo. Tissue culture allows a complete analysis of the sequence of reactions from the initial stage, and also of the chromosomal mechanism involved in the operation. In the study of cytogenetics in relation to plant breeding, tissue, and embryo, culture has acquired the status of a routine technique in the laboratory. The importance of tissue culture lies principally in its capacity to secure rapid propagation of disease-free clones and of embryo culture in the production of interspecific hybrids and overcoming the incompatibility barrier. In the in vivo condition, the presence of plasmodesma and other living factors, which cannot necessarily be reproduced exactly in vitro, help in the process of transport and uptake of food between cell and cell; therefore, under cultural conditions, the access of food at intracellular sites is a problem, which needs constant attention. There are essentially two methods for protoplast isolation based on the principle whether the enzymes are to be put simultaneously or sequentially. For chromosome analysis, it is desirable to centrifuge the protoplasts and take the sediment with nuclei.