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The regulation of cis-polyisoprene production (natural rubber) from Hevea brasiliensis

D'Auzac J., Jacob J.L., Prévôt J.C., Clément A., Gallois R., Crestin H., Lacote R., Pujade-Renaud V., Gohet E.. 1997. In : Pandalai S.G. (ed.). Recent research developments in plant physiology. Vol. 1. Trivandrum : Research Singpost, p. 273-332.

It is classically accepted that latex yield is limited by the duration of the latex flow after tapping, and by the laticiferous system capability to regenerate its content. Numerous hypothesis about coagulation mechanisms are critically reviewed.The simulation of latex production by bark treatment with an ethylene releaser is also consistently taken into account. Concerning the regeneration of the laticiferous cells content, the importance of sucrose supply and the mechanism of its influx are carefully considered, as well as the regulation of the most important key enzymes of glucidic catabolism and the major role of slight variations of the ph of laticiferous cells. The regulation of isoprenic anabolism is reviewed from acetyl-CoA to cis-polyisoprene, and the possibility that HMG-CoA reductase may be submitted to a regulation is considered. The analysis of a limited number of parameters (rubber, sugar, Pi and thiols content) give a Latex Diagnosis, which gives an account of the under- or overexploitation of the rubber tree. Competition for photoassimilates between the vegetative growth and the rubber yield is clearly described. The regulation of cis-polyisoprene may be sometimes catched out by too intensive exploitation systems of the tapping panel, especially by too numerous ethylenic stimulations. This Tapping Panel Dryness is accompanied by noticeable modifications of the genome expression

Mots-clés : hevea brasiliensis; latex; rendement; coagulation; Éthéphon; enzyme; métabolisme; diagnostic; trouble du métabolisme; encoche sèche; stimulation; système de saignée; diagnostic latex

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