Effects of Salinity on Growth Performacne and Internal Distribution of Na⁺, K⁺ and Cl⁻ in Vicia Faba L.

Greenhouse studies revealed that broad bean had moderate salt tolerance. Its salinity threshold was 4.56 dS/m and 50 percent grain yield reduction was observed at 9.51 dS/m. Stem retained more of Na⁺ as well as Cl⁻ ions so as to limit their accumulation in the leaves and this appeared to work satisfactorily up to moderate levels of salinity. Plants showed higher accumulation of Na⁺ than Cl⁻. Increasing levels of salinity decreased water and osmotic potentials of the first fully expanded leaves. Decrease in transpiration rates seems to be mainly due to increased leaf diffusive resistance. At higher salinity levels increased influx of Na⁺ and Cl⁻ ions to the stem and leaves, along with the accompanying reduction in K⁺ supply caused salt injury to the plants. The possible roles of these effects in governing plant performance have been discussed.