Ribulose bisphosphate carboxylase activity and photosynthesis during leaf development in the tomato

• Published in: Journal of experimental botany 1985-01, Vol.36 (171), p.1530-1541
• Main Authors: Besford, R.T, Wither, A.C, Ludwig, L.J
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; carboxylase; Carboxylation; Chloroplasts; Economic plant physiology; enzyme activity; Enzymes; Fundamental and applied biological sciences. Psychology; Kinetics; Leaf development; Leaves; Metabolism; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); Nutrition. Photosynthesis. Respiration. Metabolism; oxygenase; Photorespiration; Photosynthesis; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plants; RuBP carboxylase; Solanum lycopersicum var. lycopersicum; Sowing; Tomato
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/36.10.1530

Besford, R. T., Withers, A. C. and Ludwig, L. J. 1985. Ribulose bisphosphate carboxylase activity and photosynthesis during leaf development in the tomato.—J. exp Bot. 36: 1530–1541. The carboxylase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase and of phosphoenolpyruvate carboxylase, and the light saturated rate of net photosynthesis were measured in the developing 5th leaf of tomato plants. Values for light saturated net photosynthesis were also calculated from the measured carboxylase activities and estimates of internal CO2 and oxygen concentrations. The calculated rate using the activity of ribulose bisphosphate carboxylase alone for net CO2 assimilation in 300 mm3 dm−3 CO2 was greater than the measured rate at 80% and full expansion but less than the measured rate in younger leaves. When the activities of both the carboxylases were taken into account better agreement was evident for young leaves but the rate was further overestimated for older leaves The calculated rate for photosynthesis in 1200 mm3 dm−3 CO2, assuming saturation of ribulose bisphosphate carboxylase with RuBP, was an overestimate for young leaves but was close to the observed values for leaves near full expansion. The results are discussed in terms of measured conductances for CO2 and the availability of RuBP in the leaf