The Physiology of Flowering Plants - KHAM PHA MOI

284 REPRODUCTIVE DEVELOPMENTAPEXCENTREAPEXPERIPHERYTFL1TFL1LFYAP1LFYAP1INFLORESCENCEMERISTEMFLORALMERISTEMFig: 11:8 Shoot and flower meristem development are separated in the shoot apex. Inthe centre of the shoot apex, TFL1 is up-regulated prior to LFY and AP1. The activity of TFL1maintains the development of the shoot and represses the activity of LFY and AP1. At theapex periphery, the expression of LFY and AP1 result in the development of flowers andrepress the expression of TFL1. Therefore floral meristems develop from the apexperiphery whilst an indeterminate shoot meristem develops from the apex centre.Adapted from Ratcliffe et al. (1999).Fig: 11:9 The falsiflora mutant oftomato (Lycopersicon esculentum).(A) In wild-type tomato, flowersdevelop on inflorescences, I, borneon the main stem and leaves, L,continue to be produced. (B) Aclose-up view of an inflorescence ofwild-type tomato bearing flowers, F.(C) In the falsiflora mutant, flowersare replaced by secondaryinflorescence shoots and leaves;arrows indicate where some shootshave been removed for clarity. (D)A close-up of an inflorescence of thefalsiflora mutant, showing theconversion of flowers into shootsand leaves; secondary inflorescenceshoots, IS, have been removed forclarity. In the accompanyingdiagrams, shoots which willcontinue to produce leaves areshown as lines with arrowheads;flowers are shown as circles. FromMolinero-Rosales et al. (1999).Wild-type tomatoABfalsiflora mutantCDLFY have been found in Antirrhinum, pea, tobacco, petunia and tomato,and in the conifer Monterey pine (Pinus radiata). Figure 11.9 shows thefalsiflora mutant of tomato, in which inflorescences develop in theplace of flowers. The LFY homologue of P. radiata is appropriately