Hemp (Cannabis sativa L.) seeds : morpho-histological and histochemical characterisation

Cannabis sativa is an herbaceous plant, used for many different scopes from nutrition to fiber production. While the anatomical structure of the seed is already known, there is little information about its cytology and the distribution of metabolites. Moreover, differences between varieties used for animal feeding or human consumption have not been investigated yet. Our research aims to disentangle these aspects through a cyto-histochemical approach in two cultivars: one used for human consumption and one for animals feeding. We have observed no differences in fresh weight or in the percentage of dry matter between the cultivars. In both analysed samples, the PAS (Periodic Acid-Schiff) reaction outlined the presence of many protein storage vacuoles (PSVs) in the endosperm and in the cotyledons. In the embryo axis, epidermal cells did not show PSVs, and in the parenchymatic tissues, there were fewer vacuoles than in the endosperm and cotyledons. In all seed structures, no starch grains were observed, while we detected few vesicles stained with osmium, as they were probably rich in lipids or phenols. These data are useful from a botanical point of view and can be used for economical purposes.