[Mutagenic effect of nitrosomethylurea, modified by heat shock at early stages of sunflower seedling development].

A comparative study of chlorophyll mutations induced in sunflower seedlings of the initial line 3629 and its nuclear and plastom mutant derivatives by nitrosomethylurea (NMU) (0.015%), heat shock (HS, 40 degrees C), and their combination was performed. The spectrum and frequency of chlorophyll mutations depended on the treatment conditions and on the genotype of the lines tested. Nuclear mutant displayed highest sensitivity to NMU, HS, and their combination. The line 3629 plants displayed highest tolerance to NMU and HS. However, plastom mutants were more tolerant to the combination of the mutagens compared to the plants of the initial line.