EFFECT OF ACIDITY FACTORS ON ASPECTS OF SYMBIOTIC N₂ FIXATION OF LENS CULINARIS IN ACID SOILS

Abstract

Rhizobium strains and cultivars of lentil (Lens culinaris) tolerant to soil acidity factors (high Al, Mn, and low pH, Ca and Mo) were selected and their interaction response was studied for nodulation, nitrogenase activity and grain yield in acid soils supplemented with AlCl₃ and MnCl₂. The symbiotic development of plant was affected by low pH but more markedly by higher concentrations of Al and Mn. The content and concentrations of root exudates of acid-tolerant or sensitive cultivars were different and chemotaxis to sugars, amino acids, organic acids and root exudates were strain specific. Acid-tolerant Rhizobium strains showed higher rates of oxidation of carbohydrates and tricarboxylic acid intermediates than sensitive strains.