Increase in Leaf Mass Per Area Benefits Plant Growth at Elevated CO2 Concentration

• Published in: Annals of botany Vol. 91; no. 7; pp. 905 - 914
• Main Authors: ISHIZAKI, SHINJIRO, HIKOSAKA, KOUKI, HIROSE, TADAKI
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.06.2003; Oxford Publishing Limited (England)
• Subjects: Algorithms; Atmospherics; Carbon Dioxide - pharmacology; growth model; Key words: Elevated [CO2]; Leaf area; leaf mass per area; leaf mass ratio; leaf nitrogen; Mass ratio; Models, Biological; Nitrogen; Nitrogen - metabolism; optimal allocation; Original; Photosynthesis; Photosynthesis - drug effects; Plant cells; Plant growth; Plant Leaves - drug effects; Plant Leaves - growth & development; Plant roots; Plant Shoots - growth & development; Plants; Polygonum - growth & development; root : shoot ratio; Sensitivity analysis
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/aob/mcg097

An increase in leaf mass per area (MLA) of plants grown at elevated [CO2] is often accompanied by accumulation of non‐structural carbohydrates, and has been considered to be a response resulting from source–sink imbalance. We hypothesized that the increase in MLA benefits plants by increasing the net assimilation rate through maintaining a high leaf nitrogen content per area (NLA). To test this hypothesis, Polygonum cuspidatum was grown at ambient (370 µmol mol–1) and elevated (700 µmol mol–1) [CO2] with three levels of N supply. Elevated [CO2] significantly increased MLA with smaller effects on NLA and leaf mass ratio (fLM). The effect of change in MLA on plant growth was investigated by the sensitivity analysis: MLA values observed at ambient and elevated [CO2] were substituted into a steady‐state growth model to calculate the relative growth rate (R). At ambient [CO2], substitution of a high MLA (observed at elevated [CO2]) did not increase R, compared with R for a low MLA (observed at ambient [CO2]), whereas at elevated [CO2] the high MLA always increased R compared with R at the low MLA. These results suggest that the increase in MLA contributes to growth enhancement under elevated [CO2]. The optimal combination of fLM and MLA to maximize R was determined for different [CO2] and N availabilities. The optimal fLM was nearly constant, while the optimal MLA increased at elevated [CO2], and decreased at higher N availabilities. The changes in fLM of actual plants may compensate for the limited plasticity of MLA.