Effect of selenium Treatment on Drought Tolerance of Canola Plants

Drought is one of the most important yield limiting factors for canola (Brassica napus L. cv. Okapi). In this research, we studied effect of selenium (Se) treatment on increasing drought tolerance in canola plants under field and greenhouse conditions. In the field experiment, plants were treated with Se (5 and 10 g ha-1 as sodium selenate) two times, as both soil application and leaf spraying. In greenhouse grown plants, Se was added (at 100 μg plant-1) to the growth substrate (perlite) directly. In the field grown plants, vegetative biomass and seed yield of drought-stressed plants were significantly increased by Se application as leaf spraying. Results of the greenhouse experiment showed that, Se ameliorated growth reduction of drought-stressed canola plants through increasing plants ability for water uptake. Formation of more fine roots and increasing photosynthesis that provided more soluble sugars as osmoticum for supporting water uptake, were mechanisms for this response.