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.
Karim M. Farag and Jiwan P. Palta
Shiow Y. Wang and Miklos Faust
, phosphatidylcholine; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; PI, phosphatidylinositol; TLC, thin-layer chromatography. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore
Shiow Y. Wang and Miklos Faust
Abbreviations: DGDG, digalactosyl diglyceride; MGMG, monogalactosyl diglyceride; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; PI, phosphatidylinositol. We wish to thank Amy L. Jordan for technical assistance. Use
Qi Zhang, Jack Fry, Channa Rajashekar, Dale Bremer, and Milton Engelke
available in both cultivars. Eleven lipid groups were identified in zoysiagrass rhizomes: DGDG, MGDG, PC, phosphatidylethanolamine (PE), PA, PG, phosphatidylinositol (PI), phosphatidylserine (PS), and three Lyso groups (Lyso-PG, -PC, and -PE). The most
Kemin Su, Dale J. Bremer, Richard Jeannotte, Ruth Welti, and Celeste Yang
.66 n m di14:0-phosphatidylcholine (PC), 0.66 n m di24:1-PC, 0.66 n m 13:0-lysoPC, 0.66 n m 19:0-lysoPC, 0.36 n m di14:0-phosphatidylethanolamine (PE), 0.36 n m di24:1-PE, 0.36 n m 14:0-lysoPE, 0.36 n m 18:0-lysoPE, 0.36 n m di14
Dehua Liu, Miklos Faust, Helen A. Norman, Merle Millard, and Garry W. Stutte
Membrane lipids and cellular water states were studied in endodormant and paradormant apple buds. Paradormancy was overcome by thidiazuron while endodormant buds were forced to break after a certain period of chilling. Nuclear magnetic resonance imaging was used to determine water states in buds of different stages of dormancy. In endodormant buds, the changes in water states from a more tightly-bound to a more free form were correlated with changes in membrane fatty acid composition. The ratio of saturated/unsaturated fatty acids decreased with chilling, especially in C18:l/C18:3 molecular species of phosphatidylcholine and phosphatidylethanolamine. Bud lipase activity, which was assayed by in vitro hydrolysis of triglycerides, showed an abrupt increase after chilling treatments.
Bruce D. Whitaker
, phosphatidylethanolamine; PG, phosphatidylglycerol; PI, phosphatidylinositol; PL, phospholipid; SG, steryl glycoside; TSL, total steryl lipids (FS + ASG + SG). Use of a company or product name by the U.S. Dept. of Agriculture (USDA) does not imply approval or
Bruce D. Whitaker
MG tomato fruit were stored for four or 12 days at chilling (2C) or nonchilling (15C) temperature. Fruits stored 12 days at 15C ripened to the turning stage, whereas fruits at 2C did not ripen. Lipids of microsomes and plastids from pericarp tissue were analyzed at harvest and after four or 12 days of storage. After 12 days at either 15C or 2C, the ratio of phospholipid (PL) to protein in microsomes declined, with a concomitant increase in the ratio of total membrane sterols (TMS) to PL. The TMS/PL ratio also increased in crude plastids. In both microsomes and plastids, free sterols (FS) increased more at 2C than at 15C, and thus accounted for a larger percentage of the TMS. The ratio of stigmasterol to sitosterol in steryl lipids, particularly in FS, increased more at 15C than at 2C. The unsaturation index of fatty acids in PL and galactolipids generally increased slightly during storage at both 15C and 2C. The ratio of phosphatidylethanolamine to P-choline increased in both membrane fractions at both temperatures. In plastids, the ratio of mono- to digalactosyldiacylglycerol declined substantially at 2C but not at 15C.
Dana F. Faubion and Adel A. Kader
California-grown `Hass' avocado fruit were stored at 5C, in air or a controlled atmosphere (CA) of 2% oxygen and 5% carbon dioxide. Fruit were evaluated at 0, 2, 4, 6, 8, 10, and 12 weeks, both immediately upon removal from storage and after ripening at 20C. Severe chilling injury (flesh browning) developed in the airstored fruit after 6 weeks, while only moderate symptoms were observed in CA-stored avocado fruit after 12 weeks. Lipid peroxidation breakdown products increased during storage and ripening in both air and CA treatments. Sterols, steryl esters, steryl glycosides, glycolipids, and phospholipids were analyzed. Quantity of acylated steryl glycoside in ripe fruit changed from 34 nmoles initially, to 51 or 27 nmoles after 6 weeks at 5C in air or CA, respectively. Glycolipid fatty acid unsaturation in air-stored fruit decreased with the development of chilling injury. Fatty acid unsaturation in phospholipids (phosphatidylinositol, phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine) of air-stored avocados decreased with the development of chilling injury. CA storage delayed the development of chilling injury and the loss of fatty acid unsaturation.
Hua Zhou, Fang-Yun Cheng, Jing Wu, and Chaoying He
grapevine ( Vitis vinifera ) (77.71%, 79.33%, 89.66%, 89.08%, and 88.51%, respectively). The amino acid sequence alignment revealed that PsFT contained a conserved domain with characteristics of the phosphatidylethanolamine binding protein (PEBP) family