Figure 2.

Variation in the photosynthetic activity, determined as photosystem II yield (ΦPSII), in needles of 3-year-old maritime pine plants generated by somatic embryogenesis from not-primed (NP) or primed at 37 °C (P37) or at 50 °C (P50) megagametophytes, when subjected to a 30-day hydric stress treatment and allowed to recover for further 10 days. Data are mean ± SE of ratios referred to the initial contents determined in needles sampled during (T15), at the end of the treatment (T30), and after the recovery period (TR), in 10 replicates. For each sampling time, values following the same letter were not significantly different according to Tukey-b test (p < 0.001).