The Effect of Zinc on Germination in Species of the Genus Echium (Family Boraginaceae)

The effect of zinc on seed germination in two species of the Echium genus (Echium russicum J.F. Gmelin and Echium vulgare L.) was investigated. Zinc was used as sulphate in three different concentrations: 100 mg∕ l; 200 mg ∕ l și 300 mg ∕ l; the treatment was applied to the seeds before germination, the exposure time being short (4 hours and 8 hours). Seed germination was monitored daily for a period of 14 days. The effect of treatment on seed germination in the test species was assessed by calculating four germination indicators: final germination percentage (FGP), germination index (GI), mean germination time (MGT) and coefficient of rate germination (CRG). The results show the following: the seeds of Echium russicum germinate faster than those of Echium vulgare; statistically insignificant changes in the indicators associated with germination, except for GI in Echium vulgare for the 8 hours exposure time; reduction of germination percentage (in both species) and increase in germination time (more evident in Echium vulgare) with increasing exposure time. The test species showed tolerance throughout the germination process to the zinc concentrations used.