FIGURE 6.

Influence of Si supply on polyamines concentrations in roots and leaves of two contrasting tomato genotypes under osmotic stress. (A) Put concentration in roots, (B) Put concentration in leaves, (C) spermidine concentration in roots, (D) spermidine concentration in leaves, (E) spermine concentration in roots, and (F) spermine concentration in leaves. Plants were grown in hydroponic culture and osmotic stress was simulated by applying polyethylene glycol (PEG 6000). Si was provided at 0.75 mM for pre-cultured plants and at 1.5 mM for osmotic stressed plants. Roots and fully expanded leaves from 21-day old plants were harvested 7 days after imposition of osmotic stress. Bars indicate means ± SE. Different letters denote significant differences according to Fischer’s LSD test (p < 0.05; n = 4).