Roles of the Af and Tl genes in pea leaf morphogenesis: characterization of the double mutant (afaftltl)

Abstract

The pleiofila phenotype (afaftltl double mutant) of Pisum sativum arises from two single-gene, recessive mutations known to affect the identity of leaf pinnae, afila (af), and acacia (tl). The wild-type leaf consists of proximal leaflets and distal tendrils, whereas the pleiofila leaf consists of branched pinnae terminating in small leaflets. Using morphological measurements, histology, and SEM, we characterized the variation in leaf form along the plant axis, in leaflet anatomy, and in leaf development in embryonic, early postembryonic, and late postembryonic leaves of aftl and wild-type plants. Leaves on aftl plants increase in complexity more rapidly during shoot ontogeny than those on wild-type plants. Leaflets of aftl plants have identical histology to wild-type leaflets although they have smaller and fewer cells. Pinna initiation is acropetal in early postembryonic leaves of aftl plants and in all leaves of wild-type plants, whereas in late postembryonic leaves of aftl plants pinna initiation is bidirectional. Most phenotypic differences between these genotypes can be attributed to differential timing (heterochrony) of major developmental events.

Roles for auxin during morphogenesis of the compound leaves of pea ( Pisum sativum )

“…Knowing the origin and direction of auxin transport is important for understanding the processes in both phases. In the initiation phase, pinna primordia form in an acropetal series on the leaf axis of WT leaves when the leaf primordium is between 100 and approximately 400 lm long (Villani and DeMason 1997;DeMason and Villani 2001). The results of this study demonstrate that during this phase, the inhibitors exclusively affect leaf tip growth, suggesting that auxin is concentrated there and that during this organogenic phase of leaf development a gradient from tip to base might exist.…”

Auxin–cytokinin and auxin–gibberellin interactions during morphogenesis of the compound leaves of pea (Pisum sativum)

“…Leaf development on WT plantlets cultured on BA medium occurred as described previously (DeMason and Chawla 2004a) and closely resembled that of juvenile leaves on WT seedlings (Villani and DeMason 1997). Briefly, leaf primordia were initiated low on the hemispherical apical dome and produced a pair each of stipule and leaflet primordia by P2 (Fig.…”

Molecular heterochrony in the early development of Drosophila

“…[31][32][33][34][35]. However, Raff (15) has pointed out that heterochrony can be found in earlier as well as in later stages of development.…”