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We demonstrated that classical biophysical measurements of water dynamics on germinating diaspores (seeds and other dispersal units) can improve the understanding of the germination process in a simpler, safer, and newer way. This was done using diaspores of cultivated species as a biological model. To calculate the water dynamics measurements (weighted mass, initial diffusion coefficient, velocity, and acceleration), we used the mass of diaspores recorded over germination time. Weighted mass of germinating diaspores has a similar pattern, independent of the physiological quality, species, or genetic improvement degree. However, the initial diffusion coefficient (related to imbibition per se), velocity, and acceleration (related to the whole germination metabolism) are influenced by species characters, highlighting the degree of genetic improvement and physiological quality. Changes in the inflection of velocity curves demonstrated each phase of germination sensu stricto. There is no pattern related to the number of these phases, which could range between three and six. Regression models can demonstrate initial velocity and velocity increments for each phase, giving an idea of the management of germinative metabolism. Our finds demonstrated that germination is a polyphasic process with a species-specific pattern but still set by the degree of genetic improvement and (or) physiological quality of diaspores. Among the biophysical measurements, velocity has the greatest potential to define the germination metabolism.

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Even though exhaustively studied, dormancy alleviation in diaspores of Urochloa humidicola (Rendle) Morrone & Zuloaga remains a mystery. To clarify this, we asked the following question: could dormancy alleviation in diaspores of this species be associated with ageing, GA/ABA balance and remaining structures of the panicoid spikelet? We answer this question using diaspores of U. humidicola cv. BRS Tupi as a biological model, a cultivar with a wide edaphoclimatic range in Neotropical areas and whose diaspores possess 'deep dormancy' when dispersed. We analysed both germination and early plant development using a split-plot model. Our findings demonstrate that dormancy alleviation in diaspores of U. humidicola is a synergic phenomenon driven by crosstalk between age, GA/ABA balance and remaining structures of the panicoid spikelet covering caryopses, since this interaction acts on the dynamics of germination and early plant development. We demonstrate that: (i) spreading germination time is a maternal survival mechanism of this species, which has repercussions for occupational aggressiveness of the species; (ii) remaining structures of the panicoid spikelet covering caryopses are the main modulator of embryo development. These structures control the after-ripening process, which is modulated by some molecular factor. We also highlight that it is necessary to review concepts about dormancy of dispersal units in this grass species.

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RESUMO O fato de possuir espécies com potencial econômico ilimitado, faz com que o ambiente amazônico se torne alvo constante da biopirataria e da extração predatória dos recursos. Muitas espécies deste ambiente sequer possuem catalogação e, mesmo assim, encontram risco eminente de desaparecimento. Neste âmbito, trabalhos que reúnam dados sobre estas espécies possuem grande valor científico, cultural e econômico, sendo este o estímulo que desencadeou a produção desta revisão. Aqui a espécie Calycophyllum spruceanum (Benth.) Hook. f. ex K. Schum., uma Rubiaceae amazônica, é contemplada por meio de características botânicas, indicações etnofarmacológicas e propriedades químicas. Popularmente conhecida como mulateiro, a espécie é frequentemente receitada na etnomedicina como cicatrizante e rejuvenescedor, além de ser usada no controle de manchas de pele. Como peculiaridade botânica, mulateiro apresenta tronco retilíneo com epiderme fina esverdeada que evolui para uma periderme castanho-escuro, que é anualmente renovada. Em termos químicos, há destaque para a presença de alcalóides, taninos e, sobretudo, secoiridóides (7-metoxididerrosideo, 6´-acetil-β-D-glucopiranosildiderrosideo e 8-0-tigloildiderrosideo são peculiares à espécie). Mesmo com propriedades fotoprotetoras comprovadas, C. spruceanum ainda carece de pesquisas, sobretudo àquelas voltadas para a produção ex situ da planta e àquelas que demonstrem a relação entre a ecologia da planta e a produção de metabólitos funcionais para a indústria.

ABSTRACT The Amazonian environment is a constant target for biopiracy and predatory extraction of resources due to the species with vast economic potential. Many of these species have not even been cataloged, and yet are already at imminent risk of extinction. In this paper, Calycophyllum spruceanum (Benth.) Hook. f. ex k. Schum., an Amazonian Rubiaceae, is studied with information on its botanical characteristics, ethnopharmacological uses, and chemical properties. Popularly known as mulateiro, the species is often prescribed in ethnomedicine for healing and vitality, and is also used to control skin patches. As a botanical peculiarity, it has a thin green epidermis that evolves into a dark brown periderm, which is renewed annually. In terms of chemistry, there is emphasis on the presence of alkaloids, tannins, and, especially, secoiridoids (7-methoxydiderroside, 6′-acetyl-β-D-glucopyranosyldiderroside, and 8-O-tigloyldiderroside are peculiar to the species). Even with proven photoprotective properties, research on C. spruceanum is still lacking, in particular studies aimed at the ex situ production of the plant and those that show the relationship between the plant’s ecology and the production of functional metabolites for the industry.

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