Enhanced osmotolerance of a wheat mutant selected for potassium accumulation

A mutant of durum wheat was identified by screening a M4 population (sodium azide) for genotypes with enhanced capacity for potassium accumulation in leaves. The mutant (designated 422) was grown in field, controlled environm ent: hydroponic culture and NaCl salinized soil. Mutant 422 accumulates abo ut 5 mg/g dry weight more K than the wild-type and is less salt sensitive, based on leaf growth and germination. During vegetative growth exists a spe cific tolerance of the 422 mutant to K+ ion and a moderate tolerance to Cl- ion, in hydroponic culture. Under severe stress imposed by sails and manni tol, the mutant germinates better than wild type (WT). In soil containing i ncreasing NaCl, mutant 422 had higher potassium amount than WT, hat did not show augmented capacity to concentrate the ion in the leaves as salt stres s increased. The capability to accumulate potassium could improve tissue hy dration, because water content of 422 leaves was greater than WT and increa sed linearly in relation to leaf K+ concentration. (C) 2001 Elsevier Scienc e Ireland Ltd. All rights reserved.