PREAMBLE TO CHAPTER SEVEN
The ability to maintain and to culture surviving organs or tissue explants raises many questions—questions such as the morphological similarity of the cultured tissue to its normal counterpart in situ, and also their comparison in metabolic and biochemical terms. Such com- parisons become especially meaningful and important if the quiescent tissue in situ is known to possess unique properties or to contain charac- teristic chemical compounds, whether these be proteins or enzymes, amino acids or alkaloids, essential oils, or others. Thus, the discussion of the difficulties and the successes which have accompanied attempts to control the cultured explants so that they may simulate the behavior of the tissue or organ in situ, emerges in Chapter 7, as an appraisal of the biochemical potentialities of isolated parts of the plant body and of their cultured cells. Full control, at will, of the biosynthetic potentialities which are genetically inherent in the surviving cells of angiosperms, if achieved, could obviously lead to applications comparable to the fer- mentation industries which have exploited the metabolism of micro- organisms for so long.
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