Comparative study of seed germination and growth of Kochia prostrata and Kochia scoparia (Chenopodiaceae) under salinity

Soils of arid regions of Central Asia contain salts of different types that may differentially affect seed germination and plant development. We studied effect of NaCl, Na2SO4, 2NaCl + KCl + CaCl2 and 2Na2SO4+K2SO4+MgSO4 on germination of Kochia prostrata and Kochia scoparia seeds under a range of concentrations from 0.5 to 5% and at two constant temperature regimes +22 °C and +6 °C. The observed salt tolerance limit of germination at constant temperature +22 °C for both species was 5–6%, while at low temperature (+6 °C) this limit was 2%. The salt tolerance of young plants (before flowering) was 3% for NaCl. Low concentrations of sulfuric and mixed salts had a stimulating effect on seed germination in K. prostrata. Despite similarity of salt-tolerance limits the studied species showed a significant difference in seed recovery ability, i.e. the ability of ungerminated, salt-soaked seeds to germinate after transfer to fresh water. K. scoparia demonstrated a full germination recovery after seed transfer to distilled water while K. prostrata showed only a partial recovery.

Research highlights
► Low concentrations of sulfuric, chloride and mixed salts had a stimulating effect on seed germination in Kochia prostrata and K. scoparia.
► The observed salt tolerance limit of germination at constant temperature +22 °C for both species was 5–6%, while at low temperature (+6 °C) this limit was 2%. The salt tolerance of young plants (before flowering) was 3%.
► Despite similarity of salt-tolerance limits the studied species showed a significant difference in seed recovery ability. K. scoparia demonstrated a full germination recovery after seed transfer to distilled water while K. prostrata showed only a partial recovery.