Interaction of Salinity and Anaerobiosis in Barley and Rice

Barley and rice at the early tillering stage were exposed simultaneouslyto anaerobiosis and high NaCl]. Barley was grown at 0.5, 70,and 125 mol m^–3 NaCl, and rice at 2, 20, 40, and 80 molm^–3 NaCl. Surprisingly, anaerobiosis only slightly aggravatedthe adverse effects of high NaCl] on root and shoot growthof both species. For rice and barley grown under aerobic conditions, high NaCl]increased Na⁺] and Cl^–] and decreased K+] in both rootsand shoots. However, the changes in ion concentrations in theshoots were smaller for rice than for barley. For roots of barley, anaerobiosis decreased Na⁺], Cl^–],and K⁺] at both low and high NaCl], possibly as a result ofinhibition of active ion accumulation. For barley shoots, anaerobiosisincreased Na⁺] and Cl^–], but only at high salinity;in contrast, K⁺] was reduced by anaerobiosis at both low andhigh NaCl]. These results indicate that anaerobiosis slightlyincreased the permeability of the barley root system to Na+and Cl^–. For rice, the most important interaction between salinity andanaerobiosis occurred in the shoots, where anaerobiosis increasedNa⁺] and decreased K⁺], particularly at 40 and 80 mol m^–3NaCl, while there was no interaction between anaerobiosis andsalinity for Cl^– uptake. It is therefore suggested thatanaerobic treatment of rice decreased the selectivity for K⁺over Na⁺ of cation transport to the shoots, at least for plantsgrown at high salinities.