(American Journal of Botany. ;90:0.)
© Botanical Society of America, Inc.
Incongruence?
Cladistics vs. taxonomy: in an Invited Special Paper Verne Grant juxtaposes these approaches in current plant systematic research as rival schools. Asserting that cladists often pose their approach as superior and their results as more accurate, Grant analyzes the conceptual and evidenciary differences between the two-their use of different definitions of monophyly, different systematic units, and different types and amounts of character evidence. He argues that the claim that cladistics is superior to taxonomy is not justified.
(see p. 1263)
A paper by Tercek, Hauber, and Darwin presents an intriguing first look at genetic relationships in thermal vs. non-thermal Agrostis (bentgrass). The current view is that thermally adapted populations arose as ecotypes of nearby non-thermally adapted populations. Contrary to expectations, however, their data indicate that Yellowstone's endemic thermal Agrostis are genetically most similar to plants found in geothermal habitats of Lassen Volcanic National Park, California, USA and the Valley of the Geysers, Kamchatka, Russian Federation. A new taxon comprising thermal plant populations from these three geothermal areas may need naming.
(see p. 1306)
Logan et al. investigate the response to long-term chilling of transgenic cotton that overproduces the antioxidant enzyme glutathione reductase (GR). Their work points out that while reports in the literature (including contributions of the authors) conclude that GR overproduction offers protection against short-term abrupt chilling, it afforded no discernible benefit when chilling was imposed gradually on whole plants. This paper nicely contrasts the effects of short- vs. long-term chilling and reinforces the role of acclimation of protective processes. The importance of assessing the performance of transgenic crop plants under realistic conditions of environmental stress is clearly demonstrated.
(see p. 1400)
Caruso, Peterson, and Ridley address the important topic of how spatial and/or temporal variation in the strength or direction of selection may affect our ability to predict evolutionary response. Using related species of Lobelia with different pollination syndromes, the authors measure analogous traits in multiple populations and years, and compare selection gradients among them. They find that spatial and temporal variation exists, but is not similar for the two species, and suggest that the edaphic environment may be an important cause of variation in selection.
(see p. 1333)
