Acceleration of Membrane Senescence in Cut Carnation Flowers by Treatment with Ethylene

Abstract

The lipid microviscosity of microsomal membranes from senescing cut carnation (Dianthus caryophyllus L. cv. White Sim) flowers rises with advancing senescence. The increase in membrane microviscosity is initiated within 3 to 4 days of cutting the flowers and coincides temporaDly with petal-inroDling denoting the climacteric-like rise in ethylene production. Treatment of young cut flowers with aminoethoxyvinylglycine prevented the appearance of petal-inrolling and delayed the rise in membrane microviscosity until day 9 after cutting. When freshly cut flowers or amino- is disruption of membrane integrity and loss of intracellular compartmentation. Kende et al. (3,28) have noted a strong correlation between membrane leakiness and phospholipid breakdown in senescing flowers. Moreover, treatment of Tradescantia with ethylene accelerates the onset of membrane leakiness and phospholipid deterioration in petals, but the ethylene effect is dependent upon synthesis of new protein (28). Borochov et al. (6,7) have reported that the microviscosity of plasma membranes from rose petals rises with advancing senescence in a manner that correlates with an increase in sterol:phospholipid ratio reflecting phospholipid breakdown.Senescing carnation flowers exhibit a climacteric-like rise in ethylene production (5,17,20). In addition, exposure of carnation flowers to exogenous ethylene induces inrolling of the petals and results in increased ethylene synthesis (10, 24, 26). In the present study, we have used cut carnation flowers to examine the ability of ethylene to induce chemical and physical changes in microsomal membrane lipids of senescing petals. MATERIALS AND METHODSPlant Material. Carnation flowers (Dianthus caryophyllus L. cv. White Sim) were grown in raised beds in a greenhouse according to established culturing procedures. Mature flowers were cut at the commercial stage of development (fully open with a yellowish tinted center) and either used directly for membrane isolation or trimmed to an 8 cm stem length and placed individually in 20-ml vials containing either deionized water or test solutions. Flowers held in water or test solutions were maintained at 22°C, and the levels of water or test solutions were adjusted as necessary to 1 cm below the calyx.Treatments. For treatment with ethylene, flowers were placed in deionized H20 in specially constructed Plexiglas chambers (135 L capacity) equipped with an internal fan to promote circulation, two ports for gas flow, and a removeable front panel. Exposure to ethylene was achieved by injecting ethylene into the chambers to a final concentration of 1 ,pl/l. Throughout the exposure, the chambers were connected to an air stream containing 1 ,ld/l ethylene that was flowing at 20 ml/min. Chambers containing control flowers were flushed at the same rate with air that had been rendered ethylene-free by passage through potassium permanganate coated with aluminum silicate (Purafil, Chamblee, GA). Ethylene treatments were terminated by removing the flowers from the chambers t...

Senescence-Related Changes in ATP-Dependent Uptake of Calcium into Microsomal Vesicles from Carnation Petals

“…There are major changes in the molecular organization of microsomal membranes as carnation flowers senesce, including a decrease in phospholipid and an ensuing rise in the sterol: phospholipid ratio (27). Previous studies (16) with sarcoplasmic reticulum have indicated that a decrease in membrane phospholipid causes a reduction in Ca2+-ATPase activity.…”

“…The decline in ATP-dependent Ca2" uptake is clearly an early event in the post-harvest development of the flower, for it precedes the cimacteric-like rise in ethylene production and the appearance of petal-inrolling, symptoms that denote the onset of flower senescence (17). It also precedes the onset of deteriorative changes in microsomal membrane lipids including phospholipid depletion and a decrease in bulk lipid fluidity (27).…”

“…As plant tissues senesce, there is extensive breakdown of membrane phospholipids (27). Two Ca2" Transport and ATP Hydrolysis.…”

Bicarbonate/CO2-Facilitated Conversion of 1-Amino-cyclopropane-1-carboxylic Acid to Ethylene in Model Systems and Intact Tissues

“…Fluorescence depolarization of isolated membranes labeled with fluorescent probes was carried out essentially as described previously (30). Stock solutions of cis-PNA and trans-PNA (4 mm in absolute ethanol) as well as DPH (2 mm in THF) and TMA-DPH (2 mm in DMSO) were flushed with N2 and stored at -20°C.…”

Delay of Membrane Lipid Degradation by Calcium Treatment during Cabbage Leaf Senescence

“…Reduced membrane PL3 content during senescence is an indication of membrane breakdown, as shown for senescing carnation petals (8,22 (19), either by preharvest application (5) or by postharvest dip or vacuum infiltration (18). However, some references cited in the review paper by Ferguson (7) report acceleration of senescence.…”