All Publications

  • Co-Sensitization Patterns to Tree Nuts in a Pediatric Population Polk, B. I., Dinakar, C., Barnes, C. S., Shroba, J. A., Preston, K. A., Osnas, J. D., Humphrey, A. L., Jara, D. A., Hanson, J. R., Patel, N. N., Ciaccio, C. E. MOSBY-ELSEVIER. 2015: AB34
  • Wood density and vessel traits as distinct correlates of ecological strategy in 51 California coast range angiosperms NEW PHYTOLOGIST Preston, K. A., Cornwell, W. K., DeNoyer, J. L. 2006; 170 (4): 807-818


    Wood density and vessel characteristics are functionally interrelated, yet they may have distinct ecological associations. In a comparative study of 51 angiosperm species ranging from chaparral shrubs to riparian trees, we examined relationships among wood density and vessel traits and their ecological correlates. Mean vessel lumen area and vessel density (number mm(-2)) varied widely (7- to 10-fold). In multivariate analyses, both vessel traits were negatively correlated with wood density, which varied more narrowly (< 2-fold). Vessel density and lumen area were inversely related across species, allowing a broad range of vessel traits within a narrow range of wood density. Phylogenetic independent contrasts indicated correlated inverse evolutionary change in vessel traits. Each trait had a distinct pattern of ecological correlation -- wood density was most strongly associated with soil water, and vessel traits showed contrasting relationships with plant height. Within a narrow range of wood density, there was significant variation in vessel traits. Given their particular ecological associations, the results suggest that wood density and vessel traits describe two distinct ecological axes.

    View details for DOI 10.1111/j.1469-8137.2006.01712.x

    View details for Web of Science ID 000237353100016

    View details for PubMedID 16684240

  • Hydraulic architecture and the evolution of shoot allometry in contrasting climates AMERICAN JOURNAL OF BOTANY Preston, K. A., Ackerly, D. D. 2003; 90 (10): 1502-1512


    We used pairs of congeneric shrub species from contrasting habitats to test for repeated evolutionary divergence in leaf-stem allometry and shoot hydraulic architecture in response to water availability. Allometric relationships and mean ratios between leaf size (individual and total area and mass per shoot) and stem cross-sectional area were compared between habitats using six species pairs representing three genera (Arctostaphylos, Baccharis, Ceanothus). We measured correlations among evolutionary changes in allometric, morphological, and physiological traits using phylogenetic independent contrasts. Allometric analysis revealed habitat differences: slopes were homogeneous among species (=1.46), but the more mesic-adapted species generally supported more leaf area at a common stem cross-sectional area. Reducing bivariate allometry to a ratio obscured this pattern because ratios varied with stem size, which was unrelated to habitat. Mean individual leaf size also was not correlated with either water availability or leaf-stem allometry. Stem hydraulic conductivity was generally lower in the xeric-adapted species of each pair, and its evolution mirrored changes in shoot allometry. This study provides evidence for repeated evolutionary divergence in shoot allometry and hydraulic architecture associated with water availability and demonstrates the importance of shoot allometry to water relations, independent of leaf size.

    View details for Web of Science ID 000186077500012

    View details for PubMedID 21659103

  • Can plasticity compensate for architectural constraints on reproduction? Patterns of seed production and carbohydrate translocation in Perilla frutescens JOURNAL OF ECOLOGY Preston, K. A. 1999; 87 (4): 697-712
  • The effects of developmental stage and source leaf position on integration and sectorial patterns of carbohydrate movement in an annual plant, Perilla frutescens (Lamiaceae) AMERICAN JOURNAL OF BOTANY Preston, K. A. 1998; 85 (12): 1695-1703


    A well-integrated plant shows extensive carbohydrate translocation through the plant body. Even in highly integrated plants, however, translocation patterns will be sectorial if vascular tissue restricts carbon movement to sectors along stems. Both integration and sectorial translocation patterns are sensitive to plant architecture and thus may change as a plant develops. These patterns should vary also with the position of the source leaf because leaves at each node are unique in age and vascular relationship to the rest of the plant. I measured the effects of developmental stage and location of the source leaf on integration and sectoriality in an annual plant, Perilla frutescens, by labeling plants with C at one of three leaves and four developmental stages. Stage and source leaf affected both integration and sectoriality. Most notably, integration declined and sectoriality increased during seed fill, when resource demand at each node was high. Furthermore, translocation was least extensive from the leaf supporting the largest number of seeds on its axillary branch. These results suggest that plants are not homogeneous collections of subunits; rather, the role of each leaf in a plant's carbon budget is a function of its age and location on the plant.

    View details for DOI 10.2307/2446503

    View details for Web of Science ID 000077696200005

    View details for PubMedID 21680330