Comparative study on photosynthetic characteristics of different Catalpa bungei clones

Measurements of photosynthetic characteristics of 5 Catalpa bungei clones(1-3,1-4,004-1,015-1 and 7080) by Li6400 portable photosynthesis system were indicated that,(1) Light response curves of 5 clones were roughly the same,the maximum net photosynthetic rate(Pmax) was ranked as follows: 1-3 7080 015-1 004-1 1-4.Clone 1-3 and clone 7080 had strong light environmental adaptability,the light saturation point(LSP) of them were 1 147.97 μmol/m2.s and 1 196.31 μmol/m2.s respectively,and clone 1-4 had narrowest range of adaptation to light.(2) Total photosynthetic amount per area of 5 clones were quite different,clone 14 was the best(433 974.24 μmol/m2),and clone 1-3 was the second(401 290.20 μmol/m2).(3)Five clones’ trends of tanspiration rate(Tr) were the same as stomatal conductance(Cond),the diurnal variation curves of net photosynthetic rate(Pn) of clone 1-3,1-4 and 015-1 showed two typical peaks with obvious midday depression,but clone 004-1 and 7080 didn ’t.(4) Considering a variety of photosynthetic characteristics indicators,photosynthetic capacity of clone 1-3 was the best among 5 Catalpa bungei clones.