Grass-dwarf and normal genotypes have similar peroxidase levels when grown at 26°C. Higher levels of peroxidase activity were found in grass-dwarf lines induced to remain vegetative at low temperatures of 15°C than in the same lines grown at 26°C which is adequate for reproductive development. Peroxidase activity was greatest at 15°C in Type I grass-dwarf genotypes and progressively lower in Type II, Type III and normal parental genotypes after 7 weeks’ growth. This promises a quantitative method for distinguishing different types of grass-dwarf genotypes at an early stage of growth.
Heating the shoot apical meristem of grass-dwarf genotypes to 26°C induced reproductive development and reduced peroxidase activity below that in unheated vegetative grass-dwarf plants.