Figure 5.

Contents of Cys and GSH in transgenic plants exposed to 0.1 μL L⁻¹ SO₂. Six transgenic plants from each transgenic line were exposed to 0.1 μL L⁻¹ SO₂ for 4 d. The third leaves from the top of the transgenic plants were prepared and immediately subjected to quantification of the sulfhydryl compounds. The differences of the thiol content between 0- and 2- or 4-d treatment were analyzed statistically using Student's t test. (*, P < 0.1; ***, P < 0.025; ****, P < 0.005). Data are the means of triplicate analyses ± sd. 35S-GUS, Tobacco plants transformed with a bacterial UidA gene encoding GUS using as a negative control.