Senescence inhibition and respiration induced by growth retardants and N-benzyladenine.

Senescence of Grand Rapids leaf lettuce was greatly reduced at 3 storage temperatures by post-harvest treatment with N,N-dimethylaminosuccinamic acid (Alar) and 2-chloroethyltrimethylammonium chloride (CCC), but not with (6)N-benzyladenine (BA). Conversely, Alar and CCC were inactive on broccoli while BA was markedly effective. The deterioration and discoloration of mushrooms was inhibited by Alar with no effect observed from BA or CCC.The inhibition of senescence by BA and the growth retardants was not always associated with a reduction in respiration (O(2) uptake, CO(2) evolution). BA stimulated respiration and hastened senescence in leaf lettuce accompanied by a diametrically opposite effect from Alar and CCC. Thus, BA cannot be considered a universal senescence inhibitor. The variability of senescence responses induced by different chemicals on a variety of plant tissues suggests a dissimilar mode of action or a complex interaction with native growth substances.