Vernalization, stem lignification and floral transition in Phleum

Stem lignification and resulting reduced digestibility of forage grasses is thought to be associated with the transition of apices to the reproductive stage. Seppänen et al. study timothy, Phleum pratense, and find that stem elongation and formation of the lignified sclerenchyma ring is not related to apex development but rather to a requirement for mechanical support. Both VRN1 and VRN2 homologues require a vernalization signal for expression, so the development of yield-forming tillers is regulated independently of these genes.