Changes in cellulase and pectinase activities in fruit tissues and separation zones of citrus treated with cycloheximide.

Cellulase activity increased in separation-zone tissues 1 day after "Valencia" orange (Citrus sinensis [L.] Osbeck) was treated with 20 micrograms per milliliter cycloheximide. Exocellulase was detected only in the separation zones of treated fruit, whereas endocellulase was present in zones from both treated and control fruit. Endocellulase activity in separation-zone tissue of treated fruit was nearly three times as great as that in control tissues. Cellulase activity was restricted to separation-zone tissue. Pectinase and an albedo-macerating factor activity were very low and were not influenced by the treatment. The cycloheximide effect in these experiments was apparently caused by ethylene produced by wound tissue.