Table 1.
Description of the experimental sites and sampling at each site.
Fig 1.
Description of the in situ manipulative experiment.
(A) Pair of closed serotinous cones of the same whorl of Pinus halepensis. The thick and long peduncles characteristic of this species are easily distinguishable. (B) One of the possible cases that can be observed in the experiment: ‘Positive’, i.e., detached cone opened earlier than its branched pair; b, branched cone -control-; d, detached cone.
Fig 2.
Manipulating water availability in the ex situ experiment.
(A) Photograph of the styrofoam box inside the chamber. An aluminum film cover was used to further increase isolation and prevent water heating. (B) Scheme of the experiment inside the styrofoam box. W, watered cones; L, waterless cones.
Fig 3.
Peduncle sections pertaining to serotinous cones of > 5 years from Pinus halepensis (A, B) and P. brutia (C). Xylem of (A) peduncle is entirely sapwood; (B) xylem has a typical incipient heartwood starting from the pith and (C) is entirely heartwood. (A) and (B) peduncles show living cortical tissues (phloem and cortical parenchyma), but not (C). 99% of P. halepensis cones sampled in this study were in the ‘(A)’ status.
Fig 4.
Frequency distribution for two variables in the laboratory screening experiment.
(A) Frequency distribution for temperature of cone opening and (B) for density of the scales of the cones.
Fig 5.
Cone opening at OLM site by provenance and treatment.
(A) Percentage of cone opening for some provenances with contrasting behaviour pertaining to the two different provenance groups. Provenances P 152 and P 158 are part of the Northeast group; provenances P 172 and P 241 are part of the Southwest group. This plot illustrates the significant treatment by provenance interaction found at this site. (B) Percentage of cone opening during the experiment at OLM site, by treatment. Brown shadows indicate summer seasons. b, branched cones -control-; d, detached cones.
Fig 6.
Progress of the field manipulative experiment at OLM site from 10 to 125 weeks after its setting up.
Categories meaning is the following: ‘Close’, both cones of the pair remained closed; ‘Positive’, the detached cone opened earlier; ‘Negative’, the attached cone opened earlier; ‘Open’, both cones opened between observations. Numbers in the bars correspond to the significance of McNemar’s test.