Chemical Analysis Five GLS were detected in B. oleracea leaf surface samples: glucoiberin,
sinigrin, 4-hydroxyglucobrassicin, glucobrassicin, and 4-methoxyglucobrassicin (Table 1).
No significant difference was detected between JA-treated and control leaves for the total
amount of GLS per cm2. The amounts of glucobrassicin, the most abundant glucosinolate in
these samples, 4-methoxyglucobrassicin, and sinigrin, did not significantly differ between
control and JA-treated leaves. The amounts of glucoiberin and 4-hydroxyglucobrassicin
collected in the leaf surface extracts were significantly lower for JA-treated leaves compared
to control leaves (Table 1). The same results were obtained when calculated for the GLS
content expressed as nmol per mg dry weight (not shown).