Destabilisation of lutoids in Hevea brasiliensis latex during early and late flow

Yeang H. Y., . and Othman Hashim, . Destabilisation of lutoids in Hevea brasiliensis latex during early and late flow. pp. 45-58. ISSN 0127-7065

Lutoid damage in latex exuding from the rubber tree has been associated with the onset of latex vessel plugging and the subsequent cessation of flow. The commonly held supposition that lutoid damage (and by inference latex vessel plugging) is most intense at the beginning of flow when the tree is tapped is re-examined. Damage to lutoids in latex collected at various intervals after tapping and just prior to flow cessation was assessed by the appearance of the bottom fraction of centrifuged latex and the bursting index of lutoids. Although increased bottom fraction damage was regularly observed in the initial latex fraction the very extensive damage that has previously been reported to occur immediately after tapping was found to be uncommon in regularly tapped trees. Lutoid damage as determined by the bursting index fell briefly after the initial flow (1st min) and was lowest between the 4th and 15th minute. But thereafter the bursting index increased steadily until cessation of flow by which time lutoid damage in the latex was most severe. Water potential was observed to increase as the latex became more dilute during the course of flow but it was not clear to what extent lutoid damage could be attributed to the resulting osmotic shock. Based on the results of this study a reassessment should be made of the common belief that the early flow latex is highly unstable and that latex that is exuded during the later flow is more stable.

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Abstract

Lutoid damage in latex exuding from the rubber tree has been associated with the onset of latex vessel plugging and the subsequent cessation of flow. The commonly held supposition that lutoid damage (and by inference latex vessel plugging) is most intense at the beginning of flow when the tree is tapped is re-examined. Damage to lutoids in latex collected at various intervals after tapping and just prior to flow cessation was assessed by the appearance of the bottom fraction of centrifuged latex and the bursting index of lutoids. Although increased bottom fraction damage was regularly observed in the initial latex fraction the very extensive damage that has previously been reported to occur immediately after tapping was found to be uncommon in regularly tapped trees. Lutoid damage as determined by the bursting index fell briefly after the initial flow (1st min) and was lowest between the 4th and 15th minute. But thereafter the bursting index increased steadily until cessation of flow by which time lutoid damage in the latex was most severe. Water potential was observed to increase as the latex became more dilute during the course of flow but it was not clear to what extent lutoid damage could be attributed to the resulting osmotic shock. Based on the results of this study a reassessment should be made of the common belief that the early flow latex is highly unstable and that latex that is exuded during the later flow is more stable.

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Item Type:	Article
AGROVOC Term:	Hevea
AGROVOC Term:	Hevea brasiliensis
AGROVOC Term:	Crops
AGROVOC Term:	Plant injuries
AGROVOC Term:	Latex
AGROVOC Term:	Harvesting
AGROVOC Term:	Fractionation
AGROVOC Term:	Centrifugation
AGROVOC Term:	Distilled water
AGROVOC Term:	Tapping
Geographical Term:	Malaysia
Depositing User:	Ms. Suzila Mohamad Kasim
Last Modified:	28 Apr 2025 03:57
URI:	http://webagris.upm.edu.my/id/eprint/23358

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