Influence of Zeolite, Selenium and Silicon upon Some Agronomic and Physiologic Characteristics of Canola Grown under Salinity

The effect of soil applied zeolite, foliar application of selenium and silicon on the agronomic and physiologic traits of canola grown under salt stress conditions was investigated in two-year field experiment during 2012 and 2013. The experimental design was randomized complete blocks, arranged in factorial with 27 treatments forming combinations of zeolite (0, 5 and 10 ton ha(-1)), selenium (0, 2 and 4 g liter(-1)) and silicon (0, 2 and 4 g liter(-1)) and three replicates. The results indicated that zeolite improved plant growth in terms of plant height and increased yield and yield components of canola. In addition, biological yield, harvest index and oil percentage increased due to zeolite application. Zeolite could decrease respiration, malondialdehyde and proline in salt-stressed plants. Soluble sugars and potassium content increased in response to zeolite application while sodium content significantly decreased. Selenium led to an increase in plant height, silique number, seed number in silique, biological yield, harvest index and oil percentage, while respiration, malondialdehyde, proline and sodium decreased on account of selenium application. Similarly, silicon had a significant effect on growth and agronomic traits and increased them. Silicon promoted chlorophyll synthesis while preventing malondialdehyde, proline and sodium accumulation in plant tissues. Catalase and superoxide dismutase activities were suppressed by using silicon on plants. Interaction between zeolite and selenium was significant on leaf relative water content, photosynthesis, chlorophyll content and activity of antioxidant enzymes. In addition, seed weight, seed yield, photosynthesis and soluble sugar content were affected by selenium and silicon application.