In situ 13CO2 labelling of rubber trees reveals a seasonal shift in the contribution of the carbon sources involved in latex regeneration

Duangngam Onouma, Desalme Dorine, Thaler Philippe, Kasemsap Poonpipope, Sathornkich Jate, Satakhun Duangrat, Chayawat Chompunut, Angeli Nicolas, Chantuma Pisamai, Epron Daniel. 2020. In situ 13CO2 labelling of rubber trees reveals a seasonal shift in the contribution of the carbon sources involved in latex regeneration. Journal of Experimental Botany, 71 (6) : 2028-2039.

https://doi.org/10.1093/jxb/erz551

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Quartile : Outlier, Sujet : PLANT SCIENCES

Résumé : Rubber trees (Hevea brasiliensis) are the main source of natural rubber, extracted from latex, which exudes from the trunk after tapping. Tapped trees require large amounts of carbon (C) to regenerate the latex after its collection. Knowing the contribution of C sources involved in latex biosynthesis will help in understanding how rubber trees face this additional C demand. Whole crown 13CO2 pulse labelling was performed on 4-year-old rubber trees in June, when latex production was low, and in October, when it was high. 13C content was quantified in the foliage, phloem sap, wood, and latex. In both labelling periods, 13C was recovered in latex just after labelling, indicating that part of the carbohydrate was directly allocated to latex. However, significant amounts of 13C were still recovered in latex after 100 d and the peak was reached significantly later than in phloem sap, demonstrating the contribution of a reserve pool as a source of latex C. The contribution of new photosynthates to latex regeneration was faster and higher when latex metabolism was well established, in October, than in June. An improved understanding of C dynamics and the source–sink relationship in rubber tree is crucial to adapt tapping system practices and ensure sustainable latex production.

Mots-clés Agrovoc : Hevea brasiliensis, latex, régénération naturelle, physiologie végétale, métabolisme des glucides, saisonnalité, variation saisonnière, traceur radioactif

Mots-clés libres : Carbohydrates, Carbon allocation, Hevea brasiliensis, Latex regeneration, Mean residence times, Reserves, Stable isotope labelling

Classification Agris : F60 - Physiologie et biochimie végétale

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

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