Premium
Phytochrome photoreceptors mediate plasticity to light quality in flowers of the Brassicaceae
Author(s) -
Weinig Cynthia
Publication year - 2002
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.89.2.230
Subject(s) - phytochrome , petal , biology , brassicaceae , botany , arabidopsis thaliana , gynoecium , brassica rapa , pollen , mutant , brassica , gene , stamen , genetics , red light
The family of phytochrome photoreceptors mediates stem‐elongation responses to ambient ratios of red : far‐red light (R : FR). Although phytochrome genes are expressed in flowers in addition to vegetative parts, nothing is known about floral plasticity to R : FR or the pleiotropic effects of phytochrome genes on flowers. Here, the following floral morphologies were compared: (1) wild‐type Arabidopsis thaliana and Brassica rapa plants experiencing high R : FR characteristic of sunlight vs. low R : FR typical of foliar shade and (2) wild‐type and phytochrome‐deficient A. thaliana plants. Wild‐type A. thaliana exposed to low R : FR had diminished petal and pistil lengths but longer filaments for a given petal size than plants experiencing high R : FR. Brassica rapa plants had qualitatively similar responses. In comparison to wild‐type A. thaliana , mutants lacking phytochrome A had smaller flowers (smaller petals, pistils, and filaments), whereas phytochrome B‐deficient mutants exhibited longer filament lengths. These results provide the first evidence that R : FR and phytochromes affect floral phenotypes in addition to vegetative ones. Although the ecological relevance remains to be established, the observed plasticity of flowers to R : FR may be relevant to individual fitness in some species because stigma and filament positions can affect pollen removal and levels of self‐pollination.