Phosphoenolpyruvate Carboxylase and CarbonEconomy of Apple Seedlings
- 1 July 1992
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 43 (7) , 965-968
- https://doi.org/10.1093/jxb/43.7.965
Abstract
Seeds of apple cv. Golden Delicious were germinated and cultivated in the greenhouse until the third leaf emerged. Respiration ofgerminating seeds or photosynthesis of the first leaves was measured by infra-red gas analysis and porometry, respectively. To study the role of phosphoenolpyruvate carboxylase (PEPC), the dominant carboxylase in the carbon economy, its CO2 refixationpotential was related to the amount of CO2 lost in respiration. With a range of 0.2 (dry seeds) to 18 (cotyledons) μmol CO2 h–1 g–1 PEPC activity resembled or exceeded the amount of C02 lost in respiration before the third leaf developed. It is concludedthat PEPC largely contributes to economize the carbon metabolism of apple seedlings before they become photosynthetically competent.Keywords
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