Contrasting effects of N and P deprivation on the regulation of photosynthesis in tomato plants in relation to feedback limitation

• Published in: Journal of experimental botany 2003-08, Vol.54 (389), p.1957-1967
• Main Authors: de Groot, Corine C., van den Boogaard, Riki, Marcelis, Leo F. M., Harbinson, Jeremy, Lambers, Hans
• Format: Article
• Language: English
• Subjects: Absorptance; Acclimatization; Biological and medical sciences; Carbon Dioxide - metabolism; Chlorophylls; Electron Transport; feedback limitation; Feedback, Physiological; Fundamental and applied biological sciences. Psychology; Irradiance; Key words: Carboxylation activity; Leaves; Light; light harvesting; Light-Harvesting Protein Complexes; Lycopersicon esculentum - metabolism; Lycopersicon esculentum - radiation effects; Metabolism; Nitrogen; Nitrogen - deficiency; Nitrogen - metabolism; phosphorus; Phosphorus - deficiency; Phosphorus - metabolism; Photosynthesis; Photosynthesis - radiation effects; Photosynthesis, respiration. Anabolism, catabolism; Photosynthetic Reaction Center Complex Proteins; Plant growth; Plant Leaves - metabolism; Plant physiology and development; Plants; Quantum efficiency; Research Papers: Plants and the Environment; Starch - metabolism; Starches
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/erg193

The effects were studied of both nitrogen and phosphorus limitation and irradiance on the performance and operation of photosynthesis in tomato leaves (Lycopersicon esculentum Mill.). Plants were grown at low N, high N, low P or high P supply and at two irradiances. Using mature leaves, measurements were made of the irradiance dependencies of the relative quantum efficiencies of photosystems I and II, and of the rate of carbon dioxide fixation. Measurements were also made of foliar starch and chlorophyll concentrations. The results showed that photosynthetic light‐harvesting and electron‐transport activity acclimate to nutrient stress and growth irradiance such that the internal relationships between electron transport by photosystems I and II do not change; the linear relationship between ΦPSII, and ΦPSI was not affected. It was also evident that under N stress photosynthesis was reduced by a decreased light absorption and by the decreased utilization of assimilates, while P stress mainly affected the carboxylation capacity. Under N stress foliar starch levels increased and the oxygen sensitivity of CO2 fixation decreased, whereas P stress resulted in decreased starch levels and increased oxygen sensitivity of CO2 fixation. The relationship between starch accumulation and oxygen sensitivity (increased starch correlated with decreased oxygen sensitivity) was always the same across the nutrient treatments. These results are consistent with N deprivation producing an increasing limitation of photosynthesis, possibly by feedback from the leaf carbohydrate pool, whereas, although P deprivation produces a decreased rate of CO2 fixation, this is accompanied by a increase in oxygen sensitivity, suggesting that feedback limitation is decreased under P stress.