Photosynthetic Characteristics of B.tianquaninsis J.T.Pan

The light-response of photosynthetic rate of B.tianquaninsis J.T.Pan was measured by Li-6400 Portable Photosynthesis.The results showed that the light saturation point(LSP),light compensation point(LCP),maximum photosynthetic rate(Amax),the apparent quantum yield(α) and the rate of dark respiration(Rd) were 1 267.633μmol·m-2·s-1,14.293μmol·m-2·s-1,9.866μmolCO2·m-2·s-1,0.079mol·mol-1 and 1.134μmolCO2·m-2·s-1,respectively.The net photosynthetic rate,stomatal conductance and transpiration rate increased rapidly with the light intensity increasing,while cell interval concentration of CO2 decreased.The water use efficiency(WUE) of B.tianquaninsis J.T.Pan varied with the parabola model while the PAR increased.When the PAR reach 400μmol·m-2·s-1,the WUE increased linearly,and then decreased gradually.In a word,B.tianquaninsis J.T.Pan can adapt strongly to week light capability and it is a heliophilous plant with strong shade-tolerance.So the B.tianquaninsis J.T.Pan can be cultivated in the higher elevation and shading habitats.