Morphoanatomical, histochemical, and molecular characterization of female Cannabis plants from three Argentine strains

Abstract

This study analyzed the morphoanatomical, histochemical, and molecular characteristics of three Cannabis sativa strains, CAT1, CAT2, and CAT3, acronyms for Argentine therapeutic strains in Spanish (Cepas Argentinas Terapéuticas), using bright light, fluorescence, and scanning electron microscopy. The strains were previously cultivated and chemically characterized at CIM, UNLP, CONICET. Five plants from each strain were collected at the end of the vegetative and flowering phases; part of the material was fixed for anatomical studies, and part was used fresh for histochemical analyses. Anatomical features of roots, stems, leaves, and flowers were analyzed, focusing on stomatal density, trichome types, and the presence of laticifers. Histochemical analyses detected phenolic compounds, cannabinoids, lipophilic compounds, and other metabolites using specific staining techniques. Additionally, short sequence repeat (SSR) molecular markers were employed to characterize and confirm the genomic identity of the strains. Morphoanatomical and histochemical traits enabled differentiation among the strains, revealing significant variations in leaflet dimensions, trichome density, and metabolic profiles. For example, CAT1 exhibited thicker leaves and larger stomata, CAT2 had a higher density of laticifers, and CAT3 showed a greater density of cannabinoid-rich glandular trichomes. Using SSR molecular markers, strain genomic identity was confirmed with a probability greater than 99.99999983%. This integrative approach, combining morphoanatomical, histochemical, and molecular analyses, highlights the unique features of CAT1, CAT2, and CAT3 and underscores the importance of molecular markers in validating strain identity.