The Physiological Adaptation Of Deyeuxia Angustifolia (Kom.) Y.L. Chang And Carex Schmidtii Meinsh Grown In The Forest-swamp Ecotones

Leaf anatomical and photosynthetic parameters of Carex schmidtii and Calamagrostis angustifolia, undisturbed representative species in forest wetland,were investigated in five types of microhabitats in Lesser Khingan area in Yichun city,Heilongjiang Province,China,to clarify the plant physiology based adaptability to microhabitats.The microhabitats included shrub-shade,larch-marsh,Alnus incana-marsh, shrub-sun and grass-marsh habitats.The results were shown as follows:1) C.schmidtii and C.angustifolia growing in shade habitats,compared with those growing in sun habitats,had the characteristics of shorter and thinner leaves,higher contents of chlorophyll a, chlorophyll b,carotenoid and total chlorophyll unit leaf area.Moreover,shade leaves had less accumulation of organic matters,lower fresh weight,dry weight and weight per unit area than those of sun leaves.2) C.schmidtii and C.angustifolia had a certain adaptability to shade microhabitats as indicated by a low level of light compensation point(LCP) and compensation point of carbon dioxide(CCP).This showed that the two species could accumulate photosynthetic product under limited light and carbon dioxide availability.Light compensation points in leaves of C.schmidtii and C.angustifolia were lowest in Alnus incana-marsh habitat that had the highest level of crown density in all the five microhabitats.Light compensation point of the leaves increased with the decrease of crown density,and the highest LCP of the leaves occurred in the grass marsh with thevalue of 29.15μmol·m^-2s-1 and 45.75μmol·m^-2s-1,respectively. However,the two species in shade habitats had a low capability of potential light utilization,as indicated by a low light saturation point and weak in light protection capability.Light saturation point in leaves of C. schmidtii was low in larch marsh and shrub-shade habitat,approximately 498μmol·m^-2s-1 only accounting for 62.2%of that in the grass marsh;leaf LSP of C.schmidtii was the lowest in Alnus incana marsh,only equal to 43,2%of that in the grass marsh.LSP in leaves of C.angustifolia growing in Alnus incana marsh and larch marsh were only 150μmol·m^-2s-1 accounting for 33.2%of that in the grass marsh.LSP in leaves of C.angustifolia growing in shrub-shade habitat was equal to 50.6%of that in the grass marsh.