Plant cell culture chemical mechanism

Carbon dioxide is, of course, fundamentally important to plants because of photosynthesis. Most plant cell cultures are heterotrophic, non-photosynthetic and use a chemical energy source. It is reasonable to suspect, however, that some of the control mechanisms for the photosynthetic dark reactions would be regulated by C02 concentration. This could affect both cell growth and, indirectly, production of useful compounds. More concretely, C02 is known to promote synthesis of ethylene [38] on the other hand, C02 concentrations of 5-10% inhibit many ethylene effects [53]. 

To remove the feedback regulation mechanism and to avoid product degradation various adsorbents have been used for the in situ separation of plant cell cultures as shown in Table 1. In situ removal with polymeric adsorbents stimulated anthraquinone production more than the adsorbent-free control in Cinchona ledgeriana cells [35]. It was found that nonionic polymeric resins such as Amberlite XAD-2 and XAD-4 without specific functional groups are suitable for the adsorption of plant metabolite [36]. The use of the natural polymeric resin XAD-4 for the recovery of indole alkaloids showed that this resin could concentrate the alkaloids ajmalicine by two orders of magnitude over solvent extraction [37] but the adsorption by this resin proved to be relatively nonspecific. A more specific selectivity would be beneficial because plant cells produce a large number of biosynthetically related products and the purification of a several chemically similar solutes mixture is difficult [16]. 

Plant cells show an extensive repertoire of chemical reaction mechanisms epoxi-dation, reduction, oxidation, hydroxylation, isomerisation. It is self-evident that plant cell cultures synthesize as enantioselectively as their mother organisms. Besides the well-known flavour extracts and single substances, also presently unknown naturally flavour chemicals and mixtures of these are in principle obtainable. Therefore the rapid progress in investigating this area is not surprising [26],... 

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