The separate or the combined effect of hypoxia and salinity on growth and ionic relations of four wheat varieties

To evaluate hypoxic-salinity tolerance in wheat varieties, three Japanese varieties (Nourin-61, Chikugo Izumi and Shirasagi Komugi, relatively salt tolerant) and one Pakistani variety (Blue Silver, relatively salt sensitive) were grown under control, hypoxia, saline and hypoxic-saline conditions. The results suggested that relatively hypoxia and salt tolerant variety Nourin-61 was capable of producing the highest relative shoot yield under combined stress conditions. On the other hand, relatively sensitive variety to both hypoxia and salinity conditions, could not withstand harmful effects of combined stress. A more close correlation of plant growth characters between salinity and hypoxic-salinity than hypoxia and hypoxic-salinity indicated that varieties with higher salt tolerance would suffer less than varieties with higher hypoxia tolerance under combined stress conditions. And the balance of Na/K ratio in shoot tissues seems to be the major evaluation factor as the tolerant variety when salinity and hypoxia stress occur together.