Rib segments excised from flower buds ofIpomoea tricolor Cav Labelng experiments using 33P as marker showed that the rate at which radioactivity was lost from phospholipids during aging was parallel to the rate at which the level of total phospholipids declined. Exogenously applied ethylene accelerated the loss of phospholipid and the senescence of rib segments while benzyladenine retarded both of these processes.Ag+, which counteracts the effect of ethylene in many plants, inhibited rolling up of the rib segments but did not affect either spontaneous and ethylene-induced ethylene generation, or phospholpid loss.In contrast, Co2+, a purported inhibitor of ethylene synthesis, reduced ethylene production, rolling up, and phosphoUpid loss. The inhibition of ethylene-induced rolling up by Co2+ could not be overcome with exogenous ethylene, however.Our results indicate that phospholipid loss is a marker for membrane degradation in rib segments. Changes in membrane integrity and in cellular compartmentation may be the basis for ethylene synthesis during aging of flower tissue.

No abstract

No abstract

No abstract

No abstract