Figure 3.

The effect of SiR impairment on sulfur metabolite levels in different tomato leaves. A, Glutathione (left) and sulfite (right) in the 2-week-old tomato plants. The metabolites were detected in cotyledons (Cot.) and the top leaves (1-2L) of SIR Ri and wild-type (WT) plants. The presented values are average ± se (n = 4 for glutathione and n = 6 for sulfite assays). B, Sulfur metabolites in leaves of 1-month-old SIR Ri and wild-type plants. The top (1-2L), the third (3L), and the fifth (5L) leaves (counted from the tops) were collected; glutathione, sulfite, sulfide, Cys, SQDG, thiosulfate, and sulfate were quantified in the samples as described in “Materials and Methods.” The presented values are average ± se (each metabolite was quantified in three to six technical repeats). The stem segments were collected between the ground and cotyledons. The presented values are average ± se (n = 3). The values denoted by different letters are significantly different according to the Tukey-Kramer honestly significant difference mean-separation test (JMP 8.0; P < 0.05). The uppercase letters reflect differences between leaves of the same genotype; the lowercase letters distinguish different genotypes.