[Leaf economics spectrum among different plant functional types in Beijing Botanical Garden, China.]

We measured leaf photosynthetic and chlorophyll fluorescence parameters as well as leaf area, dry biomass, and nitrogen content of different plant functional types (PFTs) at the Beijing Botanical Garden, and analyzed the leaf economics spectrum (LES) among different PFTs. The results showed that the plants with the life form of grasses, those with an annual type of life history, and with a C4 photosynthetic pathway might provide a quick return on investment for the species located at one end of the LES. Similarly, the plants with a life form of trees and shrubs, with a perennial type of life history, and with a C3 photosynthetic pathway might provide a slower return on investment for the species located at the other end of the LES. This indicated that plants with different PFTs might have diverse strategies that allowed them to adapt to the environment through a trade-off among leaf traits. The results showed that the LES existed among different PFTs. Remarkable diffe-rences were observed in most of the leaf traits among different PFTs. The various life forms analyzed here were ranked in the order of grasses > vines > shrubs > trees based on specific leaf area (SLA), mass-based nitrogen concentration (N_mass), mass-based photosynthetic capacity (A_mass), and photosynthetic nitrogen use efficiency (PNUE). Among the different life histories, SLA, N_mass, A_mass, and PNUE in annual species were significantly higher than those in perennial species. In addition, A_mass, PNUE, and the quantum yield of PS2 electron transport (Φ_PS2) were higher in C4 species than in C3 species. N_mass, A_mass, and SLA were significantly positively correlated with each other. SLA was significantly negatively correlated with the photochemical efficiency of PS2 in the light (F_v'/F_m'), whereas it was significantly positively correlated with PNUE.