How does the meristem of sunflower capitulum cope with tissue expansion and floret initiation? A quantitative analysis

DOSIO, GUILLERMO; TARDIEU, FRANCOIS; TURC, OLIVIER

NEW PHYTOLOGIST

Blackwell publishing ltd.

Lugar: Reino Unido; Año: 2006 vol. 170 p. 711 - 722

0028-646X

·        The co-ordination between primordium initiation and tissue expansion on the sunflower capitulum has been studied and quantified on plants with different rates of plant biomass accumulation. ·        A method was developed to quantify tissue expansion at meristem site during primordium initiation from measurements of meristem area, number of primordia and primordium area. ·        Initially, primordium initiation and tissue expansion occurred simultaneously on meristem surface. The component of tissue expansion allocated to primordium initiation, and the duration of this first phase, remained unchanged across different environments. Thereafter, primordium initiation continued without tissue expansion at meristem site resulting in the rapid decrease of meristem area, and coinciding with the lack of floret patterning near capitulum centre. ·        A set of equations was proposed to predict primordium initiation rate and floret number, with meristem initial size and rate of tissue expansion at meristem site as input variables. This formalism demonstrated the role of tissue expansion in determining the final number of florets and provided a framework to analyse the response of floret initiation to genotype and environment.