Duncan's test: within each column, same letter indicates no significant difference between treatments (P < 0.01). C: control; S: addition of 100 mM NaCl into nutrient solution; Si1 and Si2: 0.25 and 0.5mM Si as Na2SiO3 in nutrient solution, respectively.
a
Means of four replicates and each replicate includes four plants.
b
Means of four replicates and each replicate includes two plants.