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Is photomorphogenic shade avoidance adaptive? Perspectives from population biology
Author(s) -
SCHMITT J.
Publication year - 1997
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.1997.d01-96.x
Subject(s) - biology , phenotypic plasticity , trait , adaptive value , evolutionary biology , adaptation (eye) , population , selection (genetic algorithm) , natural selection , adaptive evolution , ecotype , shade avoidance , genetics , gene , mutant , neuroscience , arabidopsis , artificial intelligence , demography , sociology , computer science , programming language
Photomorphogenic shade avoidance responses provide an ideal model system for integrating genetic, physiological and population biology approaches to the study of adaptive plasticity. The adaptive plasticity hypothesis predicts that shade avoidance phenotypes induced by low ratios of red to far‐red light (R:FR) will have high relative fitness in dense stands, but will suffer a fitness disadvantage at low density. Experiments with transgenic and mutant plants in which photomorphogenic genes are disabled, as well as phenotype manipulation by means of altered R:FR, strongly support the shade avoidance hypothesis. The observation of photomorphogenic ecotypes in different selective environments also suggests that the shade avoidance response has undergone adaptive evolution. Quantitative genetic variation in R:FR sensitivity has been detected in wild populations, indicating that the evolutionary potential exists for response to natural selection. However, evolutionary response may be constrained by genetic correlations among developmentally linked traits. Therefore it cannot be assumed that an observed suite of photomorphogenic responses represents an adaptive optimum for every trait.