Growth Responses of Triticum spp. and its Allied Plants to NaCl Concentration in Culture Medium

Abstract

Morphological and physiological responses of 19 species of Triticum and its allied plants to NaCl concentration were studied. An interspecific difference was found in the changing patterns of RGR to NaCl concentration in culture solution. The changes in RGR were mainly attributed to those in NAR. Na⁺ and Cl^- contents increased and K⁺ content decreased with increasing NaCl concentration. There were also interspecific differences in the degree of increase and decrease in the ion contents. The differences in Na⁺ content in leaf blades was especially large; species with the D genome such as dinkels contained less Na⁺ in their leaf blades than others. The depressions of photosynthesis by NaCl treatment were small in wild species and large in dinkels. Those depressions were closely related with vapour diffusion resistance (r_a'+r_s'). In species of which the SLA was more than 240 cm²/g, r_a'+r_s' increased strikingly when Na⁺ content in leaf blades was low. On the other hand, in the species of which the SLA was less than 240 cm²/g, r_a'+r_s' was maintained at low level regardless of Na⁺ content. It could be, therefore, considered that primarily, the small SLA and secondly, the Na⁺ content in leaf blades was related to the salt tolerance in Triticum and its allied plants.