-The genus Cleome is widely distributed in drier areas of the tropics and subtropics. Cleome dendroides and C. rosea are Brazilian native species that occur mainly in Atlantic Forest and sandy coastal plains, respectively ecosystems negatively affected by human impacts. Cleome spinosa is frequently found in urban areas. Many Cleome species have been used in traditional medicine, as C. spinosa. In the present work, was investigated C. dendroides, C. rosea and C. spinosa germinative behavior under in vivo conditions, as well as was established suitable conditions to in vitro germination and seedling development. The in vivo germination was performed evaluating the influence of temperature, substrate and light. It was observed that only C. spinosa seeds presents physiological dormancy, which was overcome by using alternate temperatures. The substrate influenced significantly the germination of C. rosea and the seeds of C. dendroides showed the highest germination percentages in the different conditions evaluated. The post-seminal development stages under in vivo and in vitro conditions were defined. It was observed that the development was faster under in vitro than in vivo conditions. An effective methodology for in vitro germination, enabling the providing of material to experiment on plant tissue culture was established to C. dendroides and C. spinosa.

Medicinal plants are an important therapeutic option for a large share of the world’s population. To establish an in vitro culture system for the production of secondary metabolites from Hovenia dulcis, we studied the effect of auxins, cytokinins, absence of light, and silver nitrate on the development of friable callus. Callus cultures were established for the first time and used to obtain cell suspension cultures. Supplementation with KIN (Kinetin) produced calli with both compact and friable areas, while the addition of TDZ (Thidiazuron) only produced compact callus. The maintenance of cultures in the dark induced a slight enhancement on friability when the auxin PIC (Picloram) was present in the culture medium. The addition of silver nitrate promoted the formation of friable calli. Dry weight analysis showed no significant differences in biomass growth, and, therefore, 2.0 mg.L-1 was considered the most suitable treatment. The presence of silver nitrate was not required for the establishment of cell suspension cultures. Dry weight analysis of cell suspensions showed higher biomass production in the absence of silver nitrate. PIC promoted 100% of cell suspension culture formation in the absence of silver nitrate, and higher biomass production was observed with the lowest concentration (0.625 mg.L-1). No morphological differences were observed among the different concentrations of PIC. Phytochemical screening showed the presence of saponins, flavonoids, flavonols and catechins in the extracts obtained from H. dulcis calli. These results show that the cell cultures herein established are potential sources for the production of H. dulcis secondary metabolites of medicinal interest.