At the beginning and at the end of the experiment, 5 plants per
thermal regime were collected to measure the number of leaves,
the leaf dimensions (length and width) and the mean single-leaf
and total leaf area, with a LICOR 3000 Area-meter.
Flowering time was measured as days from the beginning of
the inductive thermal treatment (DBT) to: (1) the emergence of
the stem; (2) the appearance of the first visible flower bud; (3)
the first flower anthesis (beginning of flowering, corresponding
to the commercial maturity for potted plants); (4) the complete
anthesis of the inflorescence (commercial maturity for cut stems)
(Fig. 2).
Every 7 days, the stem elongation was measured on 10 plants
per treatment. The logistic function of the Verhulst model (Verhulst,
1838; Yin et al., 2003) was chosen to fit the stem elongation data: