Physiological basis for latex diagnosis of the functioning of the laticiferous system in rubber trees

Latex is a cellular cytoplasm. Knowledge of some of its important biological characteristics should therefore make it possible to assess the physiological condition to the laliciferous system and hence its ability for producing and regenerating its cellular content at a given moment. A considerable amount of biological and physiological research carried out during the last twenty years has revealed certain parameters of latex which control production directly or indirectly and which can contribute to the determination of a 'latex diagnosis'. These parameters are physical (pH, redox potential), chemical (inorganic phosphorus and magnesium contents) and biochemical or enzymatic (total solid content, sucrose and thiols contents, phosphatase activities for bursting index determination). It has been shown that under certain experimental conditions all these parameters can be correlated with production in a highly significant manner. The correlations may be positive or negative. In these cases, it is logical that the parameters might be limiting factors with regard to production, either in the field of latex flow, or in the field of cellular regeneration between two tappings. An example is given for each criterion and their physiological roles are discussed. Seasonal variations, together with the effect of stimulation and/or clone type, must be taken into account in the examination of the values of all these parameters. Definition of an under-exploited condition and an over-exploited condition of the laticiferous system is envisaged using these parameters. (Résumé d'auteur