Copper nanoparticle induced macromutation in Macrotyloma uniflorum (Lam.) Verdc. (Leguminosae): a pioneer report

Abstract

Dry seeds (moisture content: 11.41 %) of Macrotyloma uniflorum (Lam.) Verdc. (Leguminosae) are treated with copper nanoparticles (Cu-NPs) suspension (3.2, 6.4, 12.7 and 19.1 µg mL⁻¹; 24 and 48 h) for induction of macromutation. For comparison, seeds are also treated with ethyl methanesulphonate—EMS (0.25, 0.50 and 1.0 %; 3 and 6 h) and gamma irradiations (5, 10, 15, 20, 25, 30, 50 and 100 Gy). Seedling accumulation of Cu-NPs is quantified from Atomic Absorption Spectroscopic analysis. A total of eight macromutants (six viable: ‘bushy’, ‘seed-coat color’, ‘prostrate’, ‘heterophyllous leaf’, ‘broad elongated leaf’ and ‘small narrow leaf’; two non-viable: ‘viridis’ and ‘drooping leaf’) are indentified at M₂ following Cu-NPs (four types, total mutation frequency 1.72 %, viable 1.21 %), EMS (four types, total 1.62 %, viable 1.55 %) and gamma irradiation (6 types, total 2.94 %, viable 2.08 %) treatments. The viable mutants segregated at M₃ following Mendelian pattern. Mutation frequency is rather higher at initial doses of treatments. No mutants are recovered at higher doses (12.7 µg mL⁻¹, 24 h and 19.1 µg mL⁻¹, 48 h) of Cu-NPs. The mutants are cytologically normal (2n = 20) with low fertility (control: 60.6 %; mutant: 21.2–59.1 %) and viability (control: 39.6 %, mutant: 17.7–42.5 %) of pollen grains. This is the pioneer report of nanoparticles inducing phenotypic mutants, therefore can be an alternative source for conventional mutagens. Cu-NPs are cost effective and easily synthesized in the laboratory.