Salinity effects on germination, growth and mineral nutrition of Ricinus communis seedlings

Abstract

The salinity effects on the germination and the growth of greenhouse grown castor bean (Ricinus communis L.) from three local provenances (Sidi Thabet, Grombalia and Kairouan) were studied. Plants were grown in sand-perlite mixture and irrigated with solution containing 0, 2, 5, and 10 g/l NaCl. The effect of salt stress on germination was weakly pronounced in the case of castor bean for the three provenances compared to control. Moreover, salt stress induced significant differences on plant growth during the experimental period. After 80 stress days, decreases in plant height were observed. 10 g/l NaCl has an intense depressive effect on seedling stage. The seedlings have not completed their development and this is noticed for all provenances. 5 g/l NaCl has also an intense depressive effect only for Grombalia. With regards to the mineral nutrition, hypocotyls are more concentrated in Na + and Cl -than the other organs. Thus, we observed a slight increase in K + concentration for 2 and 5 g/l NaCl compared to control, especially for Kairouan in stems. Based on the stability of the tolerance to salinity from germinative stage to seedlings stage, the provenance of Kai rouan was identified as the most tolerant and the provenance of Grombalia as the most sensitive to salt toxicity.