Interaction of Salinity and Anaerobiosis in Barley and Rice

Abstract

Barley and rice at the early tillering stage were exposed simultaneously to 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 mol m⁻³ NaCl. Surprisingly, anaerobiosis only slightly aggravated the adverse effects of high [NaCl] on root and shoot growth of both species. For rice and barley grown under aerobic conditions, high [NaCl] increased [Na⁺] and [Cl⁻] and decreased [K+] in both roots and shoots. However, the changes in ion concentrations in the shoots 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 of inhibition of active ion accumulation. For barley shoots, anaerobiosis increased [Na⁺] and [Cl⁻], but only at high salinity; in contrast, [K⁺] was reduced by anaerobiosis at both low and high [NaCl]. These results indicate that anaerobiosis slightly increased the permeability of the barley root system to Na+ and Cl⁻. For rice, the most important interaction between salinity and anaerobiosis occurred in the shoots, where anaerobiosis increased [Na⁺] and decreased [K⁺], particularly at 40 and 80 mol m⁻³ NaCl, while there was no interaction between anaerobiosis and salinity for Cl⁻ uptake. It is therefore suggested that anaerobic treatment of rice decreased the selectivity for K⁺ over Na⁺ of cation transport to the shoots, at least for plants grown at high salinities.