title: [Variations of photosynthetic parameters in CO2 acclimation of Citrus grandis leaves].
abstract: Plastic pots with sand and vermiculite were used to grow Citrus grandis saplings, and 0.05 mmol P (normal P level, P) and 0.1 mmol P (higher P level, 2P) nutrient solution were supplied every week. The saplings were grown under atmospheric CO2(about 39 Pa) and doubled CO2 partial pressure (81 +/- 5 Pa) for 45 d. The Pn-Pi curve was measured under higher irradiation (1150 mumol.m-2.s-1) by CI-301PS Photosynthesis System (CID, Inc), and the Pn-PAR curve was measured under higher CO2 partial pressure (PCO2 56 Pa). The results showed that the maximum rate of photosynthesis for 2P plants was 13.3% higher than that of P plants under atmospheric CO2 partial pressure. Regardless of P and 2P plants, the maximum photosynthetic rate under doubled CO2 partial pressure was lower than that under atmospheric CO2 partial pressure, but the photosynthetic rate of 2P plants was higher than that of P plants under doubled CO2 partial pressure. 2P plants had a higher apparent quantum efficiency and light energy conversion efficiency (P < 0.05) than P plants, but no change in gamma*, Rd and the ratio between carboxylation rate (Vc) and oxygenation rate (Vo) of Rubisco (P > 0.05) wwere found. The Vcmax and Jmax of 2P plants were 8.3% and 12.5% higher than those of P plants under atmospheric CO2 partial pressure, respectively, and 2P plants also had higher Vcmax and Jmax than P plants under double CO2 partial pressure. The partitioning coefficient of leaf nitrogen in Rubisco and in thylakoid light-harvesting component was varied in CO2 acclimation, but it was not in bioenergetics. It may suggest that an increasing phosphorus supply would promote the phosphorus turnover in photosynthetic carbon cycle, and increase the photosynthetic rate under doubled CO2 partical pressure. Increaing phosphorus supply may be a way to regulate the photosynthetic parameter of plants in CO2 acclimation.
authors.affiliation: South China Institute of Botany, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Guchou
authors.initials: G
authors.lastname: Sun
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zeng
authors.forename: Shaolin
authors.initials: S
authors.lastname: Peng
mesh_terms: D000064:Acclimatization; D002245:Carbon Dioxide / Q000378:metabolism*; D002957:Citrus / Q000378:metabolism*; D010313:Partial Pressure; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide