Silicon nutrition in alleviating salt stress in apple plant

Salinity is one of the major environmental stresses that adversely affect fruit yield and quality. Thus, finding an effective way of ameliorating salinity damage is important for sustainable fruit production. Silicon (Si) treatment effectively counteracts the effects of many abiotic stress factors such as salinity, drought, cold, iron deficiency. To probe into the potential alleviating salinity malignant effects, we investigated the protective roles of Si. An apple plant (Malus domestica Borkh.) cv. ‘Fuji’ grafted on M9 clonal rootstock was chosen for the experiment and imposed to salinity stress for 4 months with 35 mM NaCl. Si with different three doses (0.5, 1 and 2 mM) was applied to the roots of the salt-stressed apple plants except control. Si treatments inhibited apple plants growth depression through increasing stomatal conductivity, chlorophyll and decreasing electrolyte leakage. 0.5 mM Si improved root : shoot dry weight under salinity condition. The lowest values of membrane permeability were found in 0.5 and 2 mM Si treatments (21.45 and 21.55%, respectively) while salt had the highest value (48.43%). Salt exhibited a rapid decrease in stomatal conductivity by 49% compared to the control. We hypothesis that Si treatment contributed to cell walls, involving membrane stabilizing and fortification. Our findings showed that Si increased apple plant tolerance against salinity