Effect of Salinity on Growth, Ions Distribution, Accumulation and Chlorophyll Concentrations in Two Canola (Brassica napus L.) Cultivars

Salinity is a major environmental factor that influences rapeseed production in arid and semi-arid regions of central and southern Iran. In this study, effect of applied NaCl on shoot and root growth and distribution and accumulation of Na, Cl, K, Ca and Mg in the canola plant (Brassica napus L. cv: Hayola 308 and cv: PP 401) was investigated. The experiment was arranged in a completely randomized design (CRD) under the greenhouse condition. Sodium chloride was applied at the rates of 0, 4, 8 and 12 dSm NaCl. Shoot and root 1 growth of the canola plants was inhibited by salinity and NaCl significantly decreased shoot and root dry mass of canola plants. Leaf number and shoot height were inhibited by increased salt treatments in both cultivars, although Hayola 308 was more salt-tolerant than PP 401. In 8 and 12 ds m salt treatments, Hayola 308 had 1 significantly higher root and shoot dry weights per plant than PP 401. The addition of NaCl in the soil decreased total chlorophyll concentration in plants. The total chlorophyll in Hayola 308, however, was considerably greater (50 and 35%) than in PP 401 at 8 and 12 dS m salt treatments, respectively. Concentrations of Na and 1 Cl ions were significantly increased in parallel to amount of NaCl. On the contrary, K concentration in canola plant shoots and roots was significantly decreased with increasing salinity. The Ca concentration in the roots was declined with NaCl application, while Ca increased in the shoots. Mg ion concentration in root at first decreased and then increased. In general, it seems that at high salinity levels PP 401 cultivar was more sensitive than Hayola 308 cultivar, because of more sodium and chlorine in the shoot and more calcium and manganese in the root.