Figure 2.

Variation after a 3 h heat pulse of 37 °C (a,c) or 50 °C (b,d) in the relative gene expression of WKY (a,b) and HSP (c,d) genes, determined in needles of maritime pine plants growing in vitro. Plants were obtained by somatic embryogenesis, after priming megagametophytes at 37 °C (P37) and 50 °C (P50), as compared to control induction conditions at 23 °C (NP). * significant differences when compared to 0 h data, according to Tukey test (p ≤ 0.05).