Comparison of basic photosynthetic characteristics between exotic invader weed Mikania micrantha and its companion species.

摘要: Gas exchange in leaves of selected plants was measured by using LCA-4 portable photosynthesis and transpiration system (ADC, England). Analysis the difference net photosynthetic rate (Pn) between Mikania micrantha its companion species also made. Results were as follows : (1) micrantha, a herbaceous vine, had strong capacity for CO2 fixation, Pn being 21 .56 μmol CO２ m-2S-1, which higher than that accompanying somewhat woody twiner Pueraria lobata (16.97) climbing herb Ipomoea cairica (14.55), close to annual Bidens bipinnata (24.32), with exception grass Miscanthus floridulus (33.77). (2) leaf stomatal conductance (Gs) increased before noon time started decrease after 12:00, extent decrement little, revealable lagged more those understory shrubs, together high light compensation point (1002 umol m-2s-1), it is suggested intrinsically heliophylic species. (3) Compared sun floridulus, showed capability acclimation shade environment, observed quantum use efficiency lower point, evidence maintaining at about 2 m-2s-1 when incident forest lowered 70 m-2s-1. The information presented this paper would be helpful understanding aspects fast growing spreading, large biomass great production, distribution patterns nature. It might useful advanced study on control approaches growth development exotic weed.