Tetraploid induction in savory (Satureja khuzistanica): cytological, morphological, phytochemical and physiological changes

Abstract

Satureja khuzitanica, due to having phenolic compounds such as carvacrol in its essential oil and rosmarinic acid in its extract has strong antioxidant and antimicrobial properties and remarkable effects for treating several diseases. In this study, polyploidy induction was performed using 0.00, 0.05, 0.10, and 0.20% (w/v) colchicine and three treatment duration of 6, 12, and 24 h on one-week-old seedlings. Treated seedlings were transplanted to the medium culture and were regenerated. After three regenerations, tetraploid clones were identified by flow cytometry technique and chromosome counting. 2C DNA values in diploid (2n = 2x = 30) and induced tetraploid (2n = 4x = 60) were 1.43 ± 0.02 pg and 2.61 ± 03 pg, respectively. The highest tetraploid induction efficiency was 30%, obtained by colchicine concentration of 0.05% and the treatment duration of 6 h. The morphological, physiological, and phytochemical characteristics were measured in diploid and autotetraploid plants. Most of the studied traits in tetraploid plants including leaf length and width, stem diameter, stomata size, area, density, leaf guard cell size, flavonoid, phenol, soluble sugar, and essential oil yield increased significantly but stomata density decreased. In conclusion application of tetraploid induction in S. khuzistanica could be used to increase the quantity of secondary metabolites. It also can be promising to introduce a new genotype with higher phenolic compounds and drug effectiveness. The successful tetraploid induction of Khuzistan savory led to an increase in morphological parameters, biomass, essential oil yield, and phenolic compounds.