Figure 2.

Proline content in needles of maritime pine plants derived from somatic embryos matured at different temperatures (18, 23, or 28 °C) that were employed in a heat stress experiment for 10 days at 45 °C for 3 h/day. Plants were sampled at the beginning (t0) and at the end (t10) of the stress treatment, and after a recovery period of a further 10 days (tR). Data are the mean ± SD of three replicates. Within each group of plants, values followed by the same lowercase letter did not differ significantly according to the Tukey-b test, while capital letters indicate mean separation among groups of plants sampled at the same time.