Growth consequences of plasticity of plant traits in response to light conditions

Abstract

We present a method for quantifying the growth advantage, if any, that results from the plasticity of plant traits in response to growth in high vs. low resource levels. The method, which uses two phenotypes and two resource levels, quantifies the average advantage that a phenotype has, in its own set of conditions, over the other phenotype. The method is applied to the growth of two phenotypes of Abutilon theophrasti, induced by high and low light intensity, in response to two levels of incident light intensity. We calculated the growth advantage first using relative growth rate, and second using whole-plant photosynthetic assimilation rate, as the response variable. Then we used the photosynthetic responses to changes in light intensity to calculate changes in growth rates of each phenotype when exposed to a change in light conditions. These three quantifications of growth advantage broadly agree with one another. Despite the great plasticity of its traits induced by growth in high vs. low light intensity, whole-plant plasticity did not allow Abutilon theophrasti to exhibit a significant growth advantage under these conditions. Indeed, the relative growth rate of the low light phenotype greatly exceeded that of the high light phenotype in high incident light conditions. This may have resulted from the higher leaf area ratio of the low light phenotype. Furthermore, the high light phenotype had significantly greater transpiration rate in both light conditions. For these reasons we suggest that light-induced plasticity of traits in Abutilon theophrasti may confer advantage in response to the variation in vapor pressure deficit that is associated with variation in light intensity. Light-induced plasticity may also be advantageous because under high incident light conditions the high-light phenotype has greater reproductive allocation than the low-light phenotype.

Effects of inbreeding and pollen donor provenance and diversity on offspring performance under environmental stress in the rare plant Cochlearia bavarica

“…For example, seasonal changes could have been the reason for the temporal variation in perceived stressfulness of the environments and the high leaf area in the low light/high water environment on day 270 would be consistent with an allocational response to increased light capture (see, e.g. Rice & Bazzaz, 1989).…”

Evolution in Stressful Environments. I. Phenotypic Variability, Phenotypic Selection, and Response to Selection in Five Distinct Environmental Stresses

“…For longlived perennials, selection under environmental stress may lead to a metabolically more conservative phenotype characterized by reduced maximal growth rate, increased allo-cation to storage, and delayed reproduction, as envisioned by the triangle model (Grime 1977). Many perennial plant species or ecotypes characteristic of stressful environments have slower maximal growth rates than related taxa adapted to fertile environments (Clarkson 1967;Grime and Hunt 1975;Davies and Snaydon 1976;Veerkamp et al 1980;Chapin et al 1982;but see Shaw 1988;Wilson 1988;McGraw and Chapin 1989;Rice and Bazzaz 1989;Poorter and Remkes 1990;Chapin and Shaver 1996;Walters and Reich 1996). In contrast, when stress imposes selection on shorter-lived pioneer species, a stress avoidance strategy may evolve.…”

Plasticity, Morphology and Distribution in Twelve Lakeshore Plants

“…Traits examined included final biomass, root: shoot ratio and leaf number. There are several methods of quantifying plasticity (Scheiner and Goodnight 1984, Schlichting 1986, Grime et al 1986, Sultan 1987, Rice and Bazzaz 1989 but not all methods allow statistical identification of significant differences in plasticity among several species. In order to allow statistical hypothesis testing, plasticity was measured as the relative sensitivity of each species to the experimental gradient (Zuberi and Gale 1976, Falconer 1981: 123, Schlichting 1986).…”