WATER-USE AND PHOSPHORUS AND POTASSIUM STATUS OF WHEAT SEEDLINGS COLONIZED BY GAEUMANNOMYCES-GRAMINIS OR PHIALOPHORA-RADICICOLA

The water consumption and levels of phosphorus, potassium, and total minerals were measured for wheat seedlings colonized by Gaeumannomyces graminis var. tritici, Phialophora radicicola var. radicicola, or Phialophora radicicola var. graminicola. Infection by G. graminis resulted in a considerable reduction in water consumption, and reduced level of phosphorus when the supply of phosphorus to the seedlings was plentiful. Colonization by P. radicicola var. radicicola increased levels of phosphorus and potassium, but these increases varied according to the isolate of the fungus and the supply of phosphorus and potassium available to the seedlings. Colonization by P. radicicola var. graminicola resulted in reduced water consumption by the seedlings. The results are discussed in relation to stelar cell wall thickening in wheat roots colonized by P. radicicola, and the effects on nutrient uptake of mycorrhizal root systems. © 1979 Martinus Nijhoff Publishers.