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Xiujie Yin, Chao Zhang, Xin Song, and Yiwei Jiang

, chlorophyll content, RWSC content, soluble protein content, and increased root electrolyte leakage and lipid peroxidation, and decreased or increased activities of antioxidant enzymes in shoots and roots of kentucky bluegrass ( Poa pratensis ), perennial

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Shiow Y. Wang and Miklos Faust

Composition changes in galactolipids, phospholipids, and sterols in apple shoots (Malus domestica Borkh. cv. Red Delicious) from August to April were determined. The predominant fatty acids in the membrane lipids of apple shoots were palmitic acid (C16:0), linoleic acid (C18:2), and linolenic acid (C18:3). The major galactolipid components in apple shoots were monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG). The amount of MGDG and DGDG increased from autumn to spring. Galactolipids contained highly unsaturated fatty adds, mainly linoleic (18:2) and linolenic (18:3) acid. The major individual phospholipids were phosphatidylcholine (PC) and phosphatidylethaeolamine (PE). β -Sitosterol and sitosteryl ester were the predominant sterols. The phloem contained higher amounts of galactolipids, phospholipids, and sterols than did the xylem tissue. There was a significant increase in the content of galactolipids and phospholipids and onsaturation of their fatty acids during cold acclimation. A decrease in the ratio of free sterols to phospholipids also occurred in apple shoots toward cold winter months. Composition changes in galactolipids, phospholipids, and sterols that were associated with growth cessation, defoliation and cold acclimation from fall to winter, were mostly reversed following deacclimation in spring.

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Jennifer L. Baeten, Thomas C. Koch, and Irwin L. Goldman

Carrot has been bred for increased levels of pro-vitamin E α-tocopherol. This vitamin is lipid soluble. Carrot root has been shown to have measurable levels of lipid, but it is not certain if the lipid level is correlated to α-tocopherol levels. The HPLC method is needed to quantify levels of α-tocopherol. Measuring lipids may be less time consuming in a breeding program. We developed a method for extracting lipids from carrot tissue based on the Soxhlet extraction method. The Soxhlet extraction uses a non-polar ether solvent to pull lipids out of freeze-dried tissue. A collection of carrot accessions ranging in α-tocopherol concentration 0.04–0.18 ppm and carotenoid concentration 10.63–1673.76 ppm were used in this investigation. Root tissue was freeze-dried and lipid levels were measured in an experiment with two replications. The mean lipid level of root tissue was 0.05 g fat/g tissue. The range was 0–1.1 g fat/g tissue. Phenotypic correlations were performed among lipid, α-tocopherol, and β-carotene concentrations in these samples. Twenty-four samples were tested for lipid levels (12 high and 12 low). From these results, percent lipid of the root was determined. Correlations were made between the lipid data and α-tocopherol data of the given samples.

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Cristina Pisani, Mark A. Ritenour, Ed Stover, Anne Plotto, Rocco Alessandro, David N. Kuhn, and Raymond J. Schnell

using store-bought ‘Hass’ as the standard. Attributes assessed included dry matter and lipid content to determine whether these hybrids would meet California standards for avocado maturity when grown in east-central Florida. Materials and Methods Fruit

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Ravindranath V. Kanamangala, Niels O. Maness, Michael W. Smith, Gerald H. Brusewitz, Sue Knight, and Bhaggi Chinta

The unextracted and reduced lipid (supercritical carbon dioxide extraction of 22% and 27% (w/w) of total lipids) pecan [Carya illinoinensis (Wangenh.) K. Koch] kernels packaged in 21% O2, 79% N2 were analyzed for color, hexanal, sensory, fresh weight, and lipid class changes periodically during 37 weeks of storage at 25 °C and 55% relative humidity. Pecan nutmeats were lightened by partial lipid extraction. The pecan testa darkened (decreasing chromameter L*) with storage time. Most color changes occurred in the first 18 weeks. Hexanal concentration of reduced-lipid pecans was negligible throughout storage, while unextracted pecans reached excessive levels by week 22 of storage. Hexanal concentration, indicative of rancidity, was in agreement with sensory analysis results with the hexanal threshold level for objectionable rancidity ranging from 7 to 11 mg·kg-1 pecans. Weight change was negligible during storage, except in 27% reduced-lipid pecans. Free fatty acids increased with storage and were significantly higher in unextracted pecans than the reduced-lipid pecans at 0, 10, 18, 32, and 37 weeks of storage. Shelf life of pecans with partial lipid extraction was longer than unextracted pecans. In addition to decreasing the total amount of lipid available for oxidation, the free fatty acid lipid component that correlated with the development of rancidity was reduced by extraction.

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Abesinghe Arambage, James Garner, and J.L. Silva

Plasmalemma lipid fatty acid changes due to low temperature (12C) were observed in M521-1 and `Travis', chilling-tolerant and -sensitive, respectively, genotypes. Lipid fatty acid changes found in both genotypes after exposure to chilling included decreased palmitic acid (16:0) and an increased unsaturated: saturated fatty acid ratio. Changes detected only in the tolerant genotype were increased linoleic (18:2), linolenic (18:3) and erucic (22:1). Monogalactosyldiglyceride and phosphatidylglycerol were the only lipids with >50% of their fatty acids unsaturated; therefore, it was concluded that these lipids were involved in the chilling tolerance of M521-1. A reduction in arachidonic (20:4) on phosphatidylinositol from `Travis' exposed to 12C resulted in <50% unsaturation of this lipid. This change could be associated with the chilling sensitive response of `Travis'.

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Loreto R. Pascual and Robert C. Wiley

Abstract

Seven mutant maize genotypes with sweet corn backgrounds and 4 commercially grown sweet corn cultivars were harvested from 18-45 days after pollination (DAP). The lipids were extracted with chloroform-methanol 2: 1 (v/v) and separated on a silicic acid column into neutral lipids, glycolipids and phospholipids. Mutant genotypes influenced lipid development while inbred lines seemed important in amount of oil synthesized by the kernel. Crude oil and neutral lipids increased from 18-45 DAP while phospholipid and glycolipid values (mg/10 g fresh weight basis) were higher 23-28 DAP which is the prime processing time. During the developmental period studied, neutral lipids, phospholipids and glycolipids amount to 63, 20, and 12% respectively of the crude oil extracted. About 5% of the crude oil was lost in the separation procedure.

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Chana Phromtons and J. O. Garner Jr.

Storage roots of `Beauregard' and Centennial' were analyzed for total fatty acid composition and fatty acid composition by lipid class. The glycolipid, monagalactosyldiglycerol, may have been involved in chilling tolerance of `Beauregard' storage roots. This lipid had over 70 percent low-melting point fatty acids, mostly linoleic acid and linolenic acid. No consistent differences in the composition of phospholipids could be related to the chilling responses of the two sweetpotato cultivars.

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Yuefang Wang, S. Kristine Braman, Carol D. Robacker, Joyce G. Latimer, and Karl E. Espelie

Epicuticular lipids were extracted from the foliage of six deciduous and one evergreen azalea genotypes (Rhododendron sp.) and identified by gas chromatography-mass spectrometry. The relationship of leaf-surface lipid composition with measures of resistance to azalea lace bug, Stephanitis pyrioides Scott, was evaluated. Each genotype had a distinct epicuticular lipid composition. The major surface lipid components from all test taxa were n-alkanes and triterpenoids. In the most resistant genotypes [R. canescens Michaux and R. periclymenoides (Michaux) Shinners] ursolic acid, n-hentriacontane, and n-nonacosane were the most abundant epicuticular lipids. The lipids present in largest proportion among all susceptible deciduous genotypes tested were α-amyrin, β-amyrin, and n-nonacosane. The proportions of the lipid components from the same plant of each genotype varied between spring and fall samples. Among classes of lipids, n-alkanes, n-1-alkanols, and triterpenoids had significant correlations with azalea lace bug behavior on host plants. Among individual components, heptadecanoic acid, n-hentriacontane, oleanolic acid, ursolic acid and one unknown compound (with major mass spectra 73/179/192/284/311) were significantly negatively correlated with host plant susceptibility to azalea lace bug, as measured by oviposition, leaf area damaged, egg and nymphal development, and nymphal survivorship. Triacontanol, α-amyrin, β-amyrin, and three unknowns were significantly positively correlated with host plant susceptibility. Acceptance or rejection by azalea lace bug to a particular plant may be mediated by a balance of positively and negatively interpreted sensory signals evoked by plant chemicals. This study indicated that the high levels of resistance observed in R. canescens and R. periclymenoides may be due to the lesser amount or the absence of attractants and stimulants for feeding or oviposition.

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Sin-Ae Park, A-Young Lee, Hee-Geun Park, Ki-Cheol Son, Dae-Sik Kim, and Wang-Lok Lee

to infections that negatively impact the quality of life of the elderly ( Dorshkind et al., 2009 ; Palm et al., 2009 ; Suzman et al., 2015 ). Ageing is also associated with multiple systemic dysfunctions of the body, lipid metabolism disorders, and