Exploration of the functional significance of serrated leaves in New Zealand forest trees

Speaker: Bill Lee (with Jennifer Bannister and Tammo Reichgelt).

Many NZ trees have toothed/serrated leaf margins and diverse explanations exist for their functional significance, mostly derived from overseas studies on deciduous species. We survey the leaves of forest trees in NZ, investigating the presence/absence of serrations and any associated leaf pores or glands. We also compare the environmental distribution of species with either entire or serrated leaves. Serrated leaves are associated with leaf-margin and leaf-lamina hydathodes, permanent openings generally larger than stomata that are frequently attached to major veins. They may also have colletors, complex glands that appear to secrete fluid. Our previous study in New Zealand showed that trees with serrated leaves were commonly associated with high rainfall areas. The strong association between marginal hydathodes and toothed leaves supports the suggestion that serrated leaves may have a key function in regulating internal plant water pressure on regularly saturated soils.

NOTE: New meeting location! Talks are now held at the Otago Pioneer Women’s Memorial Assn., Inc., Building, 362 Moray Place, Dunedin Central.