Genotypic differences in reaction of barley root system on Mn and Fe toxicity

Abstract

The study was performed to determine genotypic differences in spring barley cultivars on resistance to 1.1 mM manganese and 1.2 mM iron at early stage of growth. Resistance level was estimated by morphologic (root length) and physiological (level of antioxidant activity, accumulation coefficient) parameters. Morphologic trait was less sensitive for cultivar differentiation in compare with physiological one. Based on relative root length index all cultivars were classified as resistant having resistance index about 80-94% for Mn and 67-76% for Fe. Reaction to Mn by change in antioxidant activity was uniform: it was increased from 4% in cv. Bionic up to 28% in cv. Farmer. According to reactions to Fe, studied cultivars were divided into three groups: high resistant (cv. Belgorodsky 100 and Farmer; increase in antioxidant activity 2 and 18% accordingly), weak resistant (cv. Forward, Bionic, and 29-11; changes were insignificant) and sensitive one (cv. 346-09; 8%-decrease in activity). For manganese accumulation coefficient is higher than for iron. The maximum accumulation coefficient for manganese was characteristic of cv. 29-11 (190), for iron - cv. Bionic (120). The genotypic specificity for root antioxidant activity can be used as a rapid test of resistance to manganese or iron in initial breeding material.