This paper presents a dataset of seed volumes calculated from length, width, and when available, thickness, abstracted from printed literature—essentially scientific journals and books including Floras and illustrated manuals, from online inventories, and from data obtained directly by the authors or provided by colleagues. Seed volumes were determined from the linear dimensions of seeds using published equations and decision trees. Ways of characterizing species by seed volume were compared and the minimum volume of the seed was found to be preferable. The adequacy of seed volume as a surrogate for seed size was examined and validated using published data on the relationship between light requirements for seed germination and seed size expressed as mass.

Stone pine (Pinus pinea L.), like other conifers, forms ectomycorrhizas (ECM), which have beneficial impact on plant growth in natural environments and forest ecosystems. An in vitro co-culture of stone pine microshoots with pure mycelia of isolated ECM sporocarps was used to overcome the root growth cessation not only in vitro but also to improve root development during acclimation phase. Pisolithus arhizus (Scop.) Rauschert and Lactarius deliciosus (L. ex Fr.) S.F. Gray fungi, were collected, pure cultured and used in in vitro co-culture with stone pine microshoots. Samples of P. arhizus and L. deliciosus for the in vitro co-cultures were collected from the pine stands southwest Portugal. The in situ characterization was based on their morphotypes. To confirm the identity of the collected material, ITS amplification was applied using the pure cultures derived from the sporocarps. Additionally, a molecular profile using PCR based genomic fingerprinting comparison was executed with other genera of Basidiomycetes and Ascomycetes. Our results showed the effectiveness of the techniques used to amplify DNA polymorphic sequences, which enhances the characterization of the genetic profile of ECM fungi and also provides an option to verify the fungus identity at any stage of plant mycorrhization.

Évora, Ap. 94, 7002-554 Évora, Portugal or preferably to lsdias@uevora.pt.

During ectomycorrhizal (ECM) establishment, biochemical signals lead to the development of complex structures in both the plant and the fungus that ultimately result in the formation of an ectomycorrhiza. The cross-talk between partners begins before physical contact. Our objective was to investigate the chemical nature of the signals during the first stages of in vitro mycorrhization of Pinus pinea with Pisolithus arhizus. For this purpose a double-phase solidÁliquid medium was expressly developed for the co-culture in order to simplify the extraction and further molecules analysis. O-coumaric acid ester was identified using HPLCÁUV and LCÁDADÁMS on the second day of co-culture and its presence was detected for up to 10 days. These results contribute to the characterization of biochemical signals during pre-colonization involving conifer species and an ECM fungus, and demonstrate the suitability of the double-phase medium developed for the growth of both organisms and for the analysis of released chemical mediators.

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