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Adaptation of pea to elevated atmospheric CO2: Rubisco, phosphoenolpyruvate carboxylase and chloroplast phosphate translocator at different levels of nitrogen and phosphorus nutrition
- Riviere-Rolland, H., Contard, P., Betsche, T.
- Plant, cell and environment 1996 v.19 no.1 pp. 109-117
- Pisum sativum, enzyme activity, ribulose-bisphosphate carboxylase, messenger RNA, phosphoenolpyruvate carboxylase, phosphorus, ion transport, chloroplasts, nutrient availability, nitrogen, plant nutrition, nutrient deficiencies, photosynthesis, carbon dioxide
- Resource allocation in high CO2 was studied with respect to plant nutrition. Pea (Pisum sativum) was grown in CO2-enriched air (1000 cm3 m-3 CO2) during the entire vegetative phase, or grown in ambient air (340 cm3 m-3 CO2), with different levels of nitrogen or phosphorus supply. Rubisco specific activity, abundance and small subunit transcript levels were unaltered at high N but declined at reduced N depending upon the degree of N deprivation. It is proposed that (a) a threshold value for the N status occurs in pea above which Rubisco is not down-regulated by high CO2 and (b) a high leaf level of soluble carbohydrates is not a sufficient condition to down-regulate Rubisco in high CO2. Phosphoenolpyruvate (PEP) carboxylase decreased, and chloroplast phosphate (P)-translocator increased, in high CO2. In contrast to Rubisco, down-regulation of PEP carboxylase was alleviated by low N and enhanced by low P. The increase in the P-translocator was little affected by N but was accentuated by low P. The increase in the P-translocator is considered to be one way of alleviating low P conditions in the chloroplast and thus re-balancing carbon partitioning between starch and soluble carbohydrates and amino acids. It is proposed that acclimation of PEP carboxylase and P-translocator reflects adaptation to metabolic perturbations caused by high CO2.