MAPPING LEAF SURFACE LANDSCAPES

Leaf surfaces provide the ecologically relevant landscapes to those or ganisms that encounter or colonize the leaf surface. Leaf surface topo graphy directly affects microhabitat availability for colonizing micro bes, microhabitat quality and acceptability for insects, and the effic acy of agricultural spray applications. Prior detailed mechanistic stu dies that examined particular fungi-plant and pollinator-plant interac tions have demonstrated the importance of plant surface topography or roughness in determining the outcome of the interactions. Until now, h owever, it has not been possible to measure accurately the topography- i.e., the three-dimensional structure-of such leaf surfaces or to reco rd precise changes in patterns of leaf surface elevation over time. Us ing contact mode atomic force microscopy, we measured three-dimensiona l coordinates of upper leaf surfaces of Vaccinium macrocarpon (cranber ry), a perennial plant, on leaves of two age classes. We then produced topographic maps of these leaf surfaces, which revealed striking diff erences bet een age classes of leaves: old leaves have much rougher su rfaces than those of young leaves. Atomic force microscope measurement s were analyzed by lag (1) autocorrelation estimates of leaf surfaces by age class. We suggest that the changes in topography result from re moval of epicuticular lipids and that the changes in leaf surface topo graphy influence phylloplane ecology. Visualizing and mapping leaf sur faces permit detailed investigations into leaf surface-mediated phenom ena, improving our understanding of phylloplane interactions.