Germinação in vitro e criopreservação de sementes de Zinnia elegans
Zinnia elegans Jacquim is a species of big cutting and ornamental potential, but its seeds have low germination percentage. This study aimed to establish a protocol for in vitro germination and water content for the cryopreservation of seeds. The length, width, thickness, and weight of one thousand seeds were determined. MS and WPM culture mediums, as well as the concentrations of gibberellic acid (GA3) were tested regarding in vitro culture. For cryopreservation, the seeds were subjected to drying on silica gel or laminar flow for different times. Then, the seeds were stored in liquid nitrogen (-196° C) for 24 hours. After this period, the seeds were thawed and inoculated into culture medium. The biometric results of seeds showed 8.6 mm average length, 4 mm width, and 0.9 mm thickness. The weight of one thousand seeds was 851 mg, characterizing them as small, lightweight, and easy to disperse. The use of MS medium with no addition of GA3 enhanced germination (67%). The initial moisture content of Z. elegans seeds was 9%. Seeds subjected up to 2 hours of drying in both treatments obtained 23% germination in silica gel and 19% in laminar flow. Z. elegans seeds may be desiccated by 4% moisture content and cryopreserved with no loss of germination potential.