Some aspects of sucrose transport and utilization in latex producing bark ofHevea brasiliensis Muel. Arg |
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Authors: | J Tupý |
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Institution: | (1) Institute of Experimental Botany, Czechoslovak Academy of Sciences, Flemingovo nám. 2, 160 00 Praha 6, Czechoslovakia |
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Abstract: | The radiotracer technique is described for transport and metabolic studies in latex producing bark. This technique provided
further evidence that carbohydrates are supplied to latex vessels as sucrose and that sucrose is readily used for rubber synthesis.
Bark treatment with ethylene resulting in latex flow stimulation is shown to activate within a few hours sucrose and water
transport into the latex vessels. The available knowledge suggests an implication of an energy-dependent process of proton
excretion which could explain the earlier observed ethylene induced alkalization of latex cytosol enhancing invertase and
sucrose utilization.
An increase of tapping intensity decreases the level of latex sucrose and changes its distribution pattern in drained bark.
There is a clonal difference in the early response to exploitation. Bark excision by conventional tapping inhibits downward
sucrose translocation, the inhibition being proportional to the surface of consumed bark above the tapping cut. Seasonal variation
in the level of latex sucrose is related to variations in sunshine duration and sucrose concentration rises during the process
of refoliation. The results stress the importance of sucrose supply to latex vessels for latex producing potentialities and
indicate an association of low sucrose availability in latex vessels with premature latex vessel degeneration and bark dryness. |
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