Studies in the Physiology of Latex

Studies in the Physiology of Latex

“…A close relationsbip between dilution and volume of latex flowing from tbe cut bas been noted in the previous paper (Gooding, 1952 a), and is strikingly shown bere during the first two weeks of tapping. Tbe dilution index decreases sharply, implying rapidly increasing dilution.…”

“…in the experiments he quotes) was taken to represent the original concentration of the latex, would be simpler. It was considered, however, that this might give a value for the latex concentration rather higher than that typical for the 'drainage area', because in earlier experiments of this series, the latex just below the cut had been found frequently to be of abnormally high concentration (Gooding, 1952 a). This was tested experimentally; three trees were tapped and successive i ml.…”

Involvement of HbPIP2;1 and HbTIP1;1 Aquaporins in Ethylene Stimulation of Latex Yield through Regulation of Water Exchanges between Inner Liber and Latex Cells in Hevea brasiliensis

“…near the tapping cut) has been known for many years to induce an influx of water in the laticifers. This so-called "latex dilution reaction" has been reported to occur at the expense of the water of the surrounding inner liber cells (Gooding, 1952;Buttery and Boatman, 1964, 1966, 1967Pakianathan, 1967) xylem tissues (Raghavendra et al, 1984), probably through the transversal vascular rays. These authors proposed that such an influx of water in the laticifers during the latex flow, leading to a further progressive decrease in the latex TSC, favored the latex flow itself and higher yield through both an increase in latex fluidity and by preventing the laticifers from collapsing under the pressure of the surrounding liber.…”

“…Upon bark tapping, the laticifers are severed and their fluid cytoplasm ("latex") flows out until coagulation processes lead to the plugging of their extremity (d 'Auzac, 1989a;Yeang, 2005). Gooding (1952) was the first to show that tapping induced, during the latex flow, progressive dilution of the latex coming from the remote areas to the tapping cut. Thus, tapping the rubber tree induces not only latex flow but also complex water circulation at the bottom of the trunk from the inner liber tissues (Lustinec et al, 1968;d'Auzac, 1989b) and from the xylem through the vascular rays, which have been reported to be numerous in H. brasiliensis (Hébant and de Faÿ , 1980).…”

“…The latex flow rate and duration are the first intrinsic factors known to limit rubber yield: the faster and the longer the latex flow, the higher the yield (d 'Auzac, 1989a). These two factors are under the control of the turgor pressure in the liber tissues (Gooding, 1952;Buttery and Boatman, 1964), of the latex dry rubber content (DRC) or total solid content (TSC), and finally of the latex coagulation efficiency (Kongsawadworakul and Chrestin, 2003). In addition, DRC is positively linked to latex viscosity and thus inversely linked to latex fluidity and yield (Van Gils, 1951).…”