Influence of respiratory inhibitors on ethyl methanesulphonate induced mutagenic effects in Hordeum vulgare.

Abstract

With an object of modifying the treatment conditions based on the concept of selection sieves, which may result in the higher mutagenic effectiveness and efficiency, barley seeds were treated with ethyl methanesulphonate (EMS) in various com-bination with non-toxic concentration of sodium azide (NaN3) and sodium arsenite (NaAsO2) as chemical modifiers. Treatments were carried out with dry, watersoaked and dried back seeds. Effects of these chemical modifiers in respect of pre-, post- and during treatment of EMS were also investigated considering the parameters, seedling injury, chromosomal aberrations, chlorophyll chimeras and sterility in M1 and chlorophyll deficient mutations as an index in M2. NaAsO2 did not induce chlorophyll mutations. However, NaN3 even in aqueous non-buffered solution induced chlorophyll mutations. As regards to their modifying action, although sodium azide and sodium arsenite both were used as common respiratory inhibitors, NaN3 was found to be most effective as a pre-treatment modifier in case of dry and dry-back seed treatments. Treatment of NaN3 soaked dried seeds with EMS synergistically increased the mutation frequencies but in general, combination treatments of NaN3 and EMS with soaked seeds were found to be highly deleterious. NaAsO2 has not been fonud to be effective as a pre-treatment modifier. It was very effective in during and post- EMS treatment combinations.