Premium
THE GENETIC ARCHITECTURE OF PLASTICITY TO DENSITY IN IMPATIENS CAPENSIS
Author(s) -
Donohue Kathleen,
Schmitt Johanna
Publication year - 1999
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1999.tb05402.x
Subject(s) - phytochrome , biology , shade avoidance , phenotypic plasticity , botany , impatiens , elongation , genetic variation , meristem , shoot , ecology , genetics , arabidopsis , gene , mutant , cultivar , red light , materials science , ultimate tensile strength , metallurgy
Plant responses to crowding may be mediated by resource availability and/or by a specific environmental cue, the ratio of red:far red wavelengths (R:FR) perceived by phytochrome. This study examined the contribution of phytochrome‐mediated photomorphogenesis to genetic variation in plastic responses to density in the annual plant Impatiens capensis . Inbred lines derived from open and woodland populations were grown under low density high density, and high density with selective removal of FR wavelengths to block phytochrome‐mediated perception of neighbor proximity. Genetic variation in plasticity to density and to the R:FR cue was detected for several traits Plants grown at high density displayed increased internode elongation; decreased branch, flower, and node production; increased menstem dormancy; and decreased leaf area and specific leaf weight compared to plants grown at low density. Stem elongation responses to density were suppressed when phytochrome perception was blocked at high density. For these phytochrome‐mediated traits, a genotype's plasticity to density was strongly correlated with its response to R:FR. Phytochrome‐mediated traits were tightly correlated with one another, regardless of the density environment. However, the responses to density of meristem allocation to branching and leaf traits were less strongly phytochrome‐mediated. These traits differed in patterns of plasticity, and their genetic correlations often differed across environments. In particular, genetic trade‐offs involving meristem allocation to branching were expressed only at low density. The observed density dependence of phenotypic and genetic correlations implies that indirect selection and the potential for correlated response to selection will depend upon the competitive environment. Thus the differential sensitivity of characters to the R:FR cue can influence the evolution of integrated plastic responses to density.