Relationship between changes in membrane permeability, respiration rate, activities of lipase and phospholipase C and ultrastructure in senescing petals of Dianthus caryophyllus (cv. White Sim)

Physiology and Biochemistry of Flower Petal Senescence

“…Electron micrographs of petals of cucumber [Smith and Butler 1971) and Ipornoea (Philips and Kende 1980) also show that plasma membranes remain intact for most of the senescence period. Similar studies on carnation petals (Burger et al 1986) showed that disintegration of the tonoplast and the plasmalemma occur only after the climacteric rise in respiration and ethylene, i.e. after wilting.…”

“…Senescing rose petals exhibited activity of both phospholipase A and phospholipase D (Borochov et al 1982b); phospholipase A, which results in the cleavage of fatty acid and the production of a lyso compound, increased with age. In carnation petals the activities of both non-specific lipase and phospholipase C were found to increase with age (Burger et al 1986); however, this happened only two days after wilting, and no change in these activities was detected during the normal course of flower senescence.…”

Ethylene and flower petal senescence: Interrelationship with membrane lipid catabolism

“…Of the various lipid metabolites that might be produced during PL catabolism, we have measured the content of DAG. This lipophiiic metabolite is a typical product of PL hydrolysis hy PLase C, the activity of which has been found to increase with senescence of carnation and petunia flowers (Burger et al 1986, Borochov et al 1994. Accordingly, our results demonstrate for the first time that also DAG content of petunia flowers increased at an early stage of petal senescence (Fig, IB).…”

“…The catabolism of the membrane PL is mediated by several enzyme cascades initiated with various phospho-lipases (PLases), among which activities of PLase A, C and D were demonstrated in flower petals (Borochov et al 1982, Burger et al, 1986, Paliyath et al 1987, McMurray and Irvine 1988, Brown et al 1990).…”

“…With advanced flower age, there is an increase in the activities of PLase A and C (Borochov et al 1982, Burger et al 1986) in flower petals, resulting in accumulation of products of these twO' enzymes. Thus, the content of free fatty acids (FFA) increases in carnation petals (Fobel et al 1987) as a result of PLase A activity.…”