We studied the influence of lysophosphatidylethanolamine (LPE) on the pattern and rate of ethylene production and respiration of tomato (Lycopersicon esculentum cv. H7155) leaflets and fruit. Leaflets that had been senescing on the plant showed a climacteric‐like rise in ethylene production but not in respiration rate which decreased continuously with leaf age. Detached leaflets had a climacteric‐like pattern in respiration whether they were incubated in complete darkness or in light. Detached leaflets incubated in the dark had higher rates of ethylene production and CO2 evolution than did light‐incubated leaves. There was no change in the pattern of ethylene production or CO2 evolution as a result of LPE treatment. However, LPE‐treated attached and detached leaflets had consistently lower rates of CO2 evolution. The reduction in CO2 evolution by LPE was most pronounced at the climacteric‐like peak of the detached leaves. LPE‐treated leaflets had a higher chlorophyll content and fresh weight and lower electrolyte leakage than the control. LPE‐treated fruits had lower rates of ethylene and CO2 production than did the control. LPE‐treated fruits also had higher pericarp firmness and lower electrolyte leakage than the control. The results of the present study provide evidence that LPE is able to retard senescence of attached leaves and detached leaves and tomato fruits. Several recent studies suggest that lysolipids can act in a specific manner as metabolic regulators. Our results suggest a specific role of lysolipid LPE in aging and senescence

P. 1993 Use cf lysophosphatidylethanolamine, a natural lipid, tc retard tomato leaf and fruit senescence. -PhysioL Plant. 87; 515-521.We studied the influence of lysophosphatidylethanolamine (LPE) on the pattern and rate of ethylene production and respiration of tcmatc (Lycopersicon esculentum cv. H7!55) leaflets and fruit. Leaflets that had been senescing on the plant showed a climacteric-like rise in ethylene prcduction but not in respiration rate which decreased continuously with leaf age. Detached leaflets had a ciimactenc-like pattern in respiration whether they were incubated in complete darkness or in light. Detached leaflets incubated in the dark had higher rates of ethylene production and CO, evolution than did light-incubated leaves. There was no change in the pattem of ethylene prcduction or COT evolution as a result cf LPE treatment. However, LPE-treated attached and detached leaflets had consistently lower rates of CO, evolution. The reduetion in CO> evolution by LPE was most pronounced at the climacteric-hke peak cf the detached leaves LPE-treated leaflets had a higher chlorophyll content and fresh weight and lower electrolyte leakage than the control. LPE-treated fruits had lower rates of ethylene and CO, production than did the ccntrol. LPE-treated fruits also had higher pericarp firmness and lower electrolyte leakage than the control. The results cf the present study provide evidence that LPE is able tc retard senescence of attached leaves and detached leaves and tomato fruits. Several recent studies suggest that lysolipids can act in a specific manner as metabolic regulators. Our results suggest a specific role of lysolipid LPE in aging and senescence.

Highly colored cranberries are desired for both fresh and juice markets. Berries accumulate more color when allowed to stay on the vines longer. However, early fall frosts often force growers to harvest before the fruit has reached its optimal color. This is especially true for the berries under the canopy. No product is currently available for grower to accelerate the color development in cranberries. Result from recent studies suggests that a natural lipid, lysophosphatidylethanolamine (LPE), can accelerate color production in fruit and, at the same time, promote shelf life. LPE is a natural lipid and is commercially derived from egg and soy lecithin. The influence of LPE on anthocyanin accumulation and storage quality of cranberry fruit (Vaccinium macrocarpon Ait. `Stevens') was studied. Cranberry plants were sprayed with LPE at about 4 weeks before commercial harvest at multiple locations. Experiments were conducted in 1997, 1998 and 1999. Fruit samples were taken at 2 and 4 weeks after spray application to determine the changes in the fruit color. Plots were wet harvested using a standard commercial method and stored in a commercial cold storage facility. Marketable fruit were evaluated at 1 and 2 months after cold storage to determine effect of LPE on shelf life of cranberries. In general, a preharvest application of LPE resulted in a 9% to 27% increase in fruit anthocyanin concentration compared to the control. LPE treatments also resulted in 8% to 12% increase in marketable fruit compared to the control following cold storage. Influence of LPE on fruit quality was more apparent after 1 month of storage. These results are consistent with the observed effects of LPE on tomatoes. Interestingly ethanol application also enhanced storage quality. Our results suggest that a preharvest application of LPE may have the potential to enhance color and prolong shelf life of cranberry fruit.

A natural lipid, lysophosphatidylethanolamine (LPE), was used as a tomato fruit ripening agent. The effect of this compound on hastening the ripening and on the defoliation of the `Heinz 7155' processing tomato and the Glamour fresh-market tomato (Lycopersicon esculentum Mill.) was compared to the effect of ethephon. Vines were sprayed to runoff in the field with a hand sprayer and fruits were harvested 2 weeks or 20 days later in a single harvest operation. LPE (100 mg liter-1) accelerated ripening of both processing and fresh-market tomatoes without defoliation. LPE-treated tomatoes had a better shelf life than the control or ethephon-treated fruit, whether they were harvested at the breaker, pink, or red stage of maturity. The combination of LPE and ethephon (100 mg liter-1) enhanced tomato ripening without damaging the foliage, suggesting that LPE can mitigate the undesirable effects of ethephon on foliage and the fruit. The LPE-related lipid phosphatidyldimethylethanol-amine dipalmitoyl (PDED) also was able to enhance some aspects of keeping quality of tomato fruits, but was not able to enhance fruit ripening. Phosphatidylethanolamine was not as effective as LPE or PDED. It appears that the active molecule of this natural lipid is the lyso form. Our results provide evidence that LPE can enhance tomato fruit ripening and postharvest storage life of vine-ripe fruits and fruits picked at early ripeness stages.

The application of ethanol for enhancing effectiveness of ethephon under field conditions on cranberry (Vaccinium macrocarpon Ait.) fruit was tested during three seasons (1986 to 1988). The formulation containing ethephon plus the surfactant Tergitol (0.3% or 0.5%, v/v) and ethanol (2.5%, 5%, or 10%) consistently increased anthocyanin content in the fruit by 28% to 54% over the control. In general, fruit size was not affected by the ethephon treatment containing ethanol and Tergitol. The application of ethephon plus surfactant did not increase the anthocyanin content in the fruit. The presence of ethanol in the ethephon and surfactant mixture, however, consistently enhanced the fruit anthocyanin content by 21% to 40% as compared to ethephon plus surfactant. No adverse effect of various treatments on vine growth or appearance was noticed over the three seasons. Chemical name used: (2-chloroethyl) phosphonic acid (ethephon).