Gas exchange in young Hevea brasiliensis (Willd. Ex A. Juss.) Müll. Arg. (Euphorbiaceae) plants in Antioquia (Colombia)

Abstract

The aim of this study was to determine the behavior of the rubber plant Hevea brasiliensis regarding its photosynthetic performance in the rubber producer regions in Nordeste and Bajo Cauca, in the department of Antioquia, Colombia, as a baseline for future clonal performance studies among environments. Gas exchange was recorded using a portable infrared gas analyzer, and for the photosynthetic parameters for seven genotypes (clones) a medium value was calculated and was later used to estimate the area under the curve. The maximum photosynthetic value was reached at 8:00 hours in San Roque (10.97 µmol [CO2] m-2s-1) and at 9:00 hours in Caucasia (7.84 µmol [CO2] m-2s-1). Maximum transpiration was 3.55 mmol [H2O] m-2s-1 in San Roque and 5.16 mmol [H2O] m-2s-1 in Caucasia, while the maximum stomatal conductance was 0.18 mol [CO2] m-2s-1 and 0.16 mol [CO2] m-2s-1 in San Roque and Caucasia, respectively. The rubber plants in Caucasia had a higher accumulated net assimilation rate (271,934 µmol [CO2] m-2day-1) than what was found in San Roque (226,287 µmol [CO2] m-2day-1), showing a difference of 45.647,52 µmol [CO2] m-2day-1. The highest carbon accumulation with the lowest light energy investment (697,638 µmol [CO2] µmol [photon]-1day1) was found in San Roque. Therefore, regarding gas exchange and the use of light energy Hevea brasiliensis showed greater environmental adaptation in San Roque.

Keywords

• Crop yield,
• environmental factors
• gas exchange
• Hevea brasiliensis