CELLULASE INVOLVEMENT IN THE ABSCISSION OF PEACH AND PEPPER LEAVES ISAFFECTED BY SALICYLIC-ACID

Phenolic compounds appear to be involved in a number of regulatory act ivities in plants. During the last decade an increasing amount of evid ence has brought to light the role played by salicylic acid in a numbe r of physiological processes, Particularly interesting is the inhibito ry effect of salicylic biosynthesis, which might make compound a usefu l tool for controlling some of the responses usually promoted by ethyl ene, Our data show that salicylic acid is actually able to reduce leaf abscission in both peach and pepper plants. Biochemical analyses have revealed that the enzyme usually involved in this phenomenon (cellula se, EC 3.2.1.4.) does not increase following activation oi leaf abscis sion in plants treated with salicylic acid, In contrast, control plant s show a marked increase in the levels of both enzyme activity and cel lulase protein, Flushing plants with exogenous ethylene in the presenc e of salicylic acid induces an increase in cellulase expression which, however, does not equal the level induced in plants without salicylic acid.