Leaf structural and photosynthetic pigment characteristics of three gallery-forest hardwood species in northeast Kansas

Leaf structural and photosynthetic pigment characteristics were measured in three dominant gallery-forest hardwood species in northeast Kansas, U.S.A. Leaves of Quercus macrocarpa and Q. muehlenbergii (more-xeric, shade-intolerant species) had significantly greater thickness, specific mass, stomatal densities and guard cell lengths than leaves of Celtis occidentalis (more-mesic, shade-tolerant). Except for guard cell lengths, these findings are consistent with differences between xeric and mesic species and shade-intolerant and shade-tolerant species. These gallery-forest species generally had much greater stomatal densities and/or lower guard-cell lengths compared to the same species or genera growing in more-mesic forests further in the east of the U.S. Compared to C. occidentalis, the Quercus species had significantly greater total chlorophyll and carotenoids, but similar chlorophyll-a:b ratios. The chlorophyll findings contradict the established idea that shade-tolerant species have greater total chlorophyll and lower chlorophyl-a:b ratios, but may be related to exceptional site and climatic factors.