Selective media with heavy metals influence on Fagopyrum esculentum Moench in vitro growth and development

The aim of research is to study the impact of the toxic effect of high doses of zinc (808-1313 mg/l) on the viability of Fagopyrum esculentum Moench test-tube regenerated plants and to obtain in vitro starting material using selective media with Zn2+. The objects of study were buckwheat regenerants of the Izumrud variety, obtained as a result of their cultivation on media with copper sulfate (161 and 184 mg/l) and microclonally propagated on Murashige-Skoog (MS) nutrient media. Morphological analysis of the test-tube microplants under study was carried out according to the parameters: plant height, length of leaf blades, number of internodes, number of leaves, presence or absence of roots, leaf color. On the 21st day of growing microclones on selective media with Zn2+, the plant height averaged 0.38-2.01 cm (3.5-14.1 times less than in the control), the length of leaf blades decreased to 3.78-8.70 mm, and their number decreased by 21.6-66.6 %. The number of internodes decreased by 1.9-3.8 times. Microplants acquired a yellow-green color, rhizogenesis was completely absent. The maximum negative impact was exerted by conditions with a concentration of 909-1313 mg/l ZnSO4 × 7H2O. The genotypes obtained as a result of selection using an increased dose of copper salt (184 mg/l) were characterized by the greatest stress resistance to zinc - root formation was observed in two studied variants of the aftereffect of zinc salt - 808-909 mg/l (I passage on MS), the survival of regenerants was 100 %; after 161 mg/l of copper salt, root formation was noted on the variant of 808 mg/l ZnSO4 × 7H2O, 3 % of microplants turned out to be non-viable. The subsequent passage (II) on MS allowed the plants to recover, and rhizogenesis resumed in all variants. The most tolerant to heavy metals lines of F. esculentum were selected.