© 1995 Heron Publishing—Victoria, Canada
Photosynthesis and canopy characteristics in genetically defined families of silver birch (Betula pendula)
Tongli Wang (1), P. M.A. Tigerstedt (1) and Anneli Viherä-Aarnio (2)
1. Department of Plant Biology, Plant and Tree Breeding, University of Helsinki, Box 27, FIN-00014 Helsinki, Finland / 2. Finnish Forest Research Institute, PL18, FIN-01301 Vantaa, Finland / Received December 6, 1994
Summary
Net photosynthetic rates (A) of leaves in upper and lower crown layers (Aupper and Alower), leaf area index (LAI), mean tilt angle (MTA), several leaf characteristics, and volume growth were observed in fast- and
slow-growing families of a 14-year-old full-sib and half-sib family progeny test of Betula pendula Roth. Each measure of net photosynthetic rate was calculated after correcting measured net photosynthesis for the effects
of environmental variables. The differences in Aupper and LAI among families were significant. The proportions of the total variance assigned to family for Aupper, Alower and LAI were 33.64, 28.93 and 54.99%, respectively. The mean Aupper and LAI of the fast-growing families were significantly higher than those of the slow-growing families, whereas the mean
Alower of the fast-growing families was significantly lower than that of the slow-growing families. There were also significant
differences among families in leaf size, leaf shape, and the ratios leaf fresh weight/area and leaf dry weight/area. Between
27.55 and 54.55% of the total variance in these characteristics could be assigned to the family effect. Volume growth was
positively correlated with Aupper and LAI, but it was most strongly correlated with Aupper × LAI.
Keywords:
leaf area index, leaf characteristics, mean tilt angle, modeling, volume growth.
