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- Rockrose land management : contribution of periodic harvesting to increase value and to control Cistus ladanifer L. shrublandsPublication . Frazão, David F.; Gonçalves, José Carlos; Silva, Amélia M.; Delgado, F.M.G.: Cistus ladanifer L. (Cistaceae) occupies extensive areas as a dominant species (shrublands) or is associated to other major forest typologies in the Iberian Peninsula. Cistus ladanifer shrublands are mostly present in oligotrophic lands with little valorisation and management and as they develop over the years (up to 20-years-old) they promote the ignition and perpetuation of fire. To contribute to the proper management and valorisation of such systems, a 5-year-old dense shrubland was evaluated for its labdanum resin, seeds, and biomass productivity using different non-destructive harvest periodicities (annual and biennial) and seasons (early, mid-, and late summer), in a two-year case-study. Annual harvest modality maximized labdanum resin productivity (reaching 230 ± 50 kg·ha−1 ·2 years−1 at late summer) and photosynthetic biomass productivity. In contrast, a biennial harvest yielded significant amounts of more diversified products. It maximized seeds productivity (reaching 75 ± 41 kg·ha−1 ·2 years−1 independently of the summer season) and lignified biomass. However, it also reached a labdanum resin productivity of 134 ± 20 kg·ha−1 ·2 yearrs−1 at late summer and a photosynthetic biomass productivity around two times lower than the annual harvest. In this study, we propose two modalities of periodic harvest to be considered as proper long cycle management practices of rockrose lands. It intends to minimize fire risks, break the vegetation auto-succession mechanism, and increase profit from nonproductive lands based on three direct outputs with a myriad of applications and valorisation pathways.
- Cistus ladanifer L. tissue culture from leaf and stem explants.Publication . Frazão, David F.; Barroca, Celina; Silva, Amélia M.; Delgado, F.M.G.; Gonçalves, José CarlosCistus ladanifer L. exudes a phenolic and terpenoid resin with interesting bioactive and aromatic properties. Despite its high abundance in the wild, this plant can be cultivated to advantage on oligotrophic and trace-elements contaminated soils. Plant tissue culture may be used to produce specific metabolites or for clonal propagation of specific genotypes for plantation. From a biotechnological perspective this is the second study that has attempted in vitro propagation of C. ladanifer from adult plant material. Its goal was to evaluate the potential of leaf and internodal stem explants from C. ladanifer for in vitro tissue culture. Three plant growth regulators were tested: 2,4-Dichlorophenoxyacetic acid (2,4-D), 6-Benzylaminopurine (BAP), and 1-Naphthaleneacetic acid (NAA). From both explants, shoots were regenerated under the influence of BAP (38%) and two types of compact calli were induced: dark green calli were induced under the influence of BAP (above 70%) and light green calli were induced under the influence of 2,4-D with or without BAP (100%). Light green calli grew between 558 and 708% during subsequent subcultures and showed rhizogenic capacity when the amounts of BAP were lower than of 2.4-D, but they showed low potential for shoot organogenesis. Dark green calli were associated with shoot organogenesis. The suitability of the two calli lines to produce metabolites and their transposition to liquid cultures is worth further study in comparison to organ in vitro cultures.