We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Tansley review Evolution of zygomorphy in monocot flowers: iterative patterns and developmental constraints.
- Authors
Rudall, Paula J.; Bateman, Richard M.
- Abstract
Here we explore morphological transitions among monocot flowers and discuss them in terms of modification of existing structures. Monocot flowers are typically arranged in five whorls (carpels, inner and outer stamens, inner and outer tepals), and are radially symmetrical, constructed around a 3-fold axis of rotational symmetry that delineates three planes of bilateral symmetry. Differential development of one or two of the three organs within a whorl inevitably emphasizes one plane of symmetry, by eliminating the other planes, rendering the whorl zygomorphic. Zygomorphy (monosymmetry) has evolved more than once in monocotyledons. Stamen suppression is a widespread aspect of zygomorphy and conforms to two broad categories of pattern. In the more frequent Pattern 1, 1–3(−5) adaxial stamens (both inner and outer) are either reduced in size or entirely suppressed. Pattern 2 involves loss, reduction or modification of at least the outer abaxial stamen. Pattern 2 often characterizes groups that are phylogenetically embedded within Pattern 1 clades, perhaps indicating that this pattern results from loss of function or overexpression of the same genes involved in establishment of Pattern 1. Heterotopy has been an important evolutionary phenomenon among Zingiberales (some stamens becoming petaloid) and perhaps grasses (petals possibly becoming sepaloid). Heterochrony is the most frequent cause of more subtle changes in the degree of bilateral symmetry shown by monocot flowers by enhancing (peramorphosis) or retarding (paedomorphosis) individual organs within specific whorls. © New Phytologist (2004) 162: 25 –44
- Subjects
HETEROCHRONY (Biology); FLOWERS; ZINGIBERALES; GENES; STAMEN
- Publication
New Phytologist, 2004, Vol 162, Issue 1, p25
- ISSN
0028-646X
- Publication type
Article
- DOI
10.1111/j.1469-8137.2004.01032.x