Effects of silicon (Si) on growth, quality and ionic homeostasis of aloe under salt stress

• Addition of silicon in formulation of irrigation solution significantly alleviated growth inhibition of salt stressed aloe.
• Leaf juice rate and its physicochemical properties of salt stressed aloe were also improved due to added silicon in nutrient solution of irrigation.
• Silicon ameliorated ionic equilibrium and homeostasis of salt stressed aloe via promoting absorption and translocation selectivity to salt ions.
• Increasing external silicon concentration inhibited decrease of proton pump activity of root tips of salt stressed aloe.

The physiological characteristics of aloe irrigated with brackish water and the relationship with ameliorative effects of silicon (Si) nutrition were studied. Results of cultivation and analysis showed that 2.0 mmol · L− 1 added Si significantly alleviated growth inhibition and quality reduction of aloe under 100 mmol · L− 1 NaCl stress; added Si significantly reduced Na+ content while increased K+ content and K+/Na+ ratio of salt stressed aloe plant, especially absorption and translocation selectivity of aloe root to K+ and Na+ were promoted, and ion homeostasis of aloe plant was kept well. Results of cross-sectional X-ray energy dispersive spectrum microanalysis of aloe root and leaf further confirmed the above findings. One of the mechanisms of silicon was its improvement to activity of plasma membrane H+-ATPase, tonoplast membrane H+-ATPase and H+-pyrophosphates of aloe root under salt stress.