ABSTRACT
Seedlings of two tomato cultivars were exposed to 0, 50, or 100 mM sodium chlroide (NaCl) stress with or without silicon (Si) for 10 days, and leaf electrolyte leakage, root activity, plant growth, and ion sodium, potassium, calcium, and magnesium (Na+, K+, Ca2+, and Mg2+) contents were determined. No significant differences were observed in total biomass and the root/crown ratio of salt-stressed plants treated with exogenous Si, but leaf electrolyte leakage of both cultivars treated with 50 mM NaCl and Si was lower than that in the same salt treatment without Si. Root activities of both cultivars were significantly affected by treatment with NaCl and exogenous Si. Application of Si induced a significant decrease in Na+ content and increases in K+, Ca2+, and Mg2+ contents in leaves of plants treated with 50 mM NaCl, and consequently the K+/Na+ and Ca2+/Na+ ratios increased by at least two times. The effects of Si on the ion contents of the roots were not notable.
Acknowledgments
The authors thank Dr Hattori from the Field Production Science Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, for his encouragement and for providing the silicon.