About the Cover
Abscission of plant organs is an active process in which cell separation takes place within a band of histologically distinct cells, termed the abscission zone. Although much is known about the physiology of abscission, far less is known about how the abscission zone forms. Periclinal chimeras have provided important information about cell-cell coordination during plant development. On pages 159-175, Szymkowiak and Irish describe a complete set of tomato periclinal chimeras that incorporate the jointless mutation which abolishes the formation of the flower pedicel abscission zone and also allows the inflorescence meristem to revert to vegetative growth. The phenotypes of the chimeras demonstrate that for normal pedicel and inflorescence development, wild-type Jointless function is required only in the third meristem layer, L3, and its derived tissues. This point is illustrated on the cover, which shows a normal abscission zone bisecting a sectored pedicel in which jointless L1-derived (green sector) or L1- and L2-derived tissues (yellow sector) overlie wild-type L3-derived tissues.
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Copyright © 2007 by the American Society of Plant Biologists
