Chlorophyll Fluorescence Of 20 Species Of Wetland Plants

In this thesis, we studied photosynthetic characteristics of 20 species of wetland plants using modulated chlorophyll fluorescence technique. 15 species were collected from the suburb of Guangzhou, they are Eichhornia crassipes, Pistia stratiotes, Jussiaea repens, Jussiaea stipulacea, Ipomoea aquatica, Sagittaria sagittifolia, Polygonum lapathifolium, Polygonum minus, Pontederia cordata, Thalia dealbata, Alternanthera philoxeroides, Commelina communis, Floscopa scandens, Colocasia tonoimo and Hygrophila megalantha; 4 species of mangroves were collected from Futian, Shenzhen, they are Acanthus ilicifolius, Kandelia candel, Sonneratia caseolaris and Sonneratia apetala; Nymphoides peltatum were collected from Taihu Lake.First, we measured whole-leaf chlorophyll fluorescence by IMAGING-PAM and analyzed the spatial heterogeneity of photosynthesis in leaves of 20 species of wetland plants. The maximal photosystem (PS) Ⅱ quantum yield of chlorophyll fluorescence after dark adaptation (Fv/Fm) showed no obvious spatial heterogeneity (CV=0.50%～ 1.79%) in all studied plant leaves, while the other parameters, such as photosynthetic active radiation (PAR) absorptivity (Abs), the effective PS Ⅱ quantum yield of chlorophyll fluorescence in illumated state (Y), photochemical quenching (qP), non-photochemical quenching (NPQ) and relative electron transport rate (rETR), showed obvious heterogeneity. Y and qP showed similar heterogeneity, while NPQ showed inverse heterogeneity to Y and qP, in all studied plant leaves. The heterogeneities of Abs and rETR were different in these plant leaves. In E. crassipes, P. stratiotes, P. cordata, T. dealbata and C. tonoimo, Abs showed no obvious heterogeneity (CV=2.58%～6.32%), rETR showed the same heterogeneity as Y and qP. In N. peltatum, P. lapathifolium, A. philoxeroides, H. megalantha, A. ilicifolius and K. candel, Y showed no obvious heterogeneity (CV=2.06%～4.51%), rETR showed the same heterogeneity as Abs. In J. repens, J. stipulacea, I. aquatica, S. sagittifolia, P. minus, C. communis, F. scandens, S. caseolaris and S. apetala, both Abs and Y have heterogeneity and affect the...