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Bridging the gaps: evolution and development of perianth fusion
Author(s) -
Zhong Jinshun,
Preston Jill C.
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13517
Subject(s) - petal , biology , perianth , evolutionary biology , primordium , stamen , botany , gene , pollen , genetics
Summary One of the most striking innovations in flower development is the congenital or postgenital union of petals (sympetaly) which has enabled dramatic specialization in flower structure and possibly accelerated speciation rates. Sympetalous flowers exhibit extraordinary variation in development, including the degree and timing of fusion, and fusion with other floral organs. Different axes of corolla tube complexity can be disentangled at the developmental level, with most variation being explained by differences in coordinated growth between interconnected and lobed regions of neighboring petal primordia, and between lower and upper portions of the corolla tube, defined by the stamen insertion boundary. Genetically, inter‐ and intra‐specific variation in the degree of petal fusion is controlled by various inputs from genes that affect organ boundary and lateral growth, signaling between different cell types, and production of the cuticle. It is thus hypothesized that the evolution and diversification of fused petals, at least within the megadiverse Asteridae clade of core eudicots, have occurred through the modification of a conserved genetic pathway previously involved in free petal development.ContentsSummary 330 I. To fuse or not to fuse: convergent origins of perianth fusion and separation 330 II. Distinct developmental mechanisms of asterid sympetaly 331 III. Rewiring of organ boundary/lateral expansion pathways in the origins of sympetaly 332 IV. Conclusions and perspectives 333Acknowledgements 334References 334