Effects of sulfur supply on sulfur content and conformation within peanut leaves

Greenhouse experiment was conducted to study content and conformation of sulfate (S)，glutathione，and insoluble S fraction within different aged peanut leaves. The content of glutathione decreased with the leaf aging increase，whereas an opposite trend was observed for SO42- content. The concentration of insoluble S was similar for all leaves. With the sufficient S supply, SO42-, glutathione, and insoluble fraction accounted for 4.4%, 4.6% and 91% of total S in the young leave, respectively. In the middle and old leaves，60% to 80% of total S accumulated as SO42-, and glutathione accounted for less than 1%. The concentrations of all S-containing compounds，particularly SO42-, decreased in the young and middle leaves without S supply. Glutathione was not a major S source for peanut during S deficiency. Low N supply aggravated the symptoms S deficiency. The different aged leaves had non-unique responses to S deficiency. Young leaves are more sensitive to S deficient than middle and old leaves.