Abstract
Photosynthetic carboxylating enzymes and the effects of light and temperature on 14CO2 efflux in two species of gymnosperm leaves were studied. The activity of RuBP carboxylase was high and that of PEP carboxylase was very low when compared to C4 plants. The CO2 compensation point was high. 14CO2 efflux was greater in light than in darkness and the ratio (L/D) increased with increase in temperature and light intensity. The inhibitors of glycolate metabolism showed decreased 14CO2 evolution in light while dark respiration was unaffected. It is concluded that both Cycas circinalis, L. and Cycas beddomei Dyer are C3 plants.
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References
Bjorkman O and Gauhl E (1969) Carboxy dismutase activity in plants with and without-carboxylation photosynthesis. Planta 88: 197–203.
Chollet R (1978) Evaluation of the light/dark 14C assay of photorespiration. Plant Physiol 61: 929–932.
Tregunna EB, Smith BN, Berry JA and Downton WJS (1970) Some methods for studying the photosynthetic taxonomy of the angiosperms. Can J Bot 48: 1209–1214.
Zelitch I (1968) Investigations on photorespiration with a sensitive 14C-assay. Plant Physiol 43: 1829–1837.
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Prabhakar, C.S., Rao, K.R. Photorespiration studies in Cycas circinalis L. and Cycas beddomei Dyer. Photosynth Res 2, 297–300 (1981). https://doi.org/10.1007/BF00056267
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DOI: https://doi.org/10.1007/BF00056267