Dynamics of photosynthesis in Eichhornia crassipes Solms of Jiangsu of China and their influencing factors

Abstract

With LI-6400 portable photosynthesis system, the photosynthetic characteristics of artificially cultured Eichhornia crassipes in Jiangsu, China, were monitored from June 1 to November 14, 2009. Both the net photosynthetic rate (Pn) in different positions and light and temperature-response curves of the top fourth leaf were measured in an open-circuit gas channel system in June, July, and August, respectively. The top third to sixth leaves matured with a high Pn in August, 2009. The values of the maximum net photosynthesis (Pmax), light component point (LCP) and apparent quantum efficiency (AQE) of the top fourth leaf of E. crassipes were 34.5±0.72 and 20.25±3.6 μmol m^-2s^-1 as well as 0.0532±0.0014, respectively, significantly higher than those in rice and maize. The light-saturation point (LSP) of leaves of E. crassipes was 2358±69 μmol m^-2s^-1, significantly higher than that in rice and much close to that in maize. The natural light intensity and temperatures in Jiangsu are suitable for E. crassipes to rapidly grow but not good enough for it to show the maximum internal photosynthetic capacity from the perspective of photosynthetic physiology, thus resulting in its low biomass in this region.

Key words: Eichhornia crassipes, photosynthetic characteristics, environmental influencing factors.