Identification of p.Methoxyallybenzene in the Pollen of the Oil Palm Elaeis guineensis Jacq.

The lipid extract prepared from the pollen of the West African,oil palm, Elaeis guineensis, was found to contain p-methoxyallylbenzenein substantial amount. The pure substance after isolation bymeans of preparative gas-liquid chromatography and steam distillationwas characterized by using a combination of g.l.c.-mass spectrometry,infrared spectrometry, and chemical reactions. Mass spectrometrygave a spectrum with a parent ion at m/e 148 corresponding tothe molecular weight and fragmentation ions at m/e 133, 121,117, 105, 91, and 77. The structure was further confirmed bymeans of the infrared spectrum which showed major peaks at 1250,920, and 815 cm^–1 corresponding to a CH₃O group, a 1,4-substitutedaromatic ring, and a RCH=CH₂ group respectively. Its chemicaland physical properties (hydrogenation, oxidation, etc.) werefound to be similar to those of its positional isomer, p-methoxy--phenylpropene.The physiological and economic importance of the compound arediscussed.     

Physiological Studies of the Sulpholipids of Diatoms

The sulpholipids of three species of freshwater and marine diatomNitzschia palae Kutz, Navicula muralis Lewin and Navicula incertaGrün, have been investigated under various culture conditions.The plant sulpholipid, sulphoquinovosyl diglyceride, was predominantlysynthesized in the light rather than in the dark while the unknownsulpholipids, designated as U₁ and U₂, were produced more inthe dark than in the light. It was found that cells starvedof carbon or sulphate utilized their sulpholipid reserve assources of these materials. Generally, cultures incubated inthe light and bubbled with air (with or without CO₂) showeda high level of incorporation of ³⁶S into sulpholipids. In culturesbubbled with oxygen-free nitrogen the incorporation of tracerwas very small. The photosynthetic and respiratory inhibitors,DCMU and DNP appreciably reduced the amount of tracer incorporatedinto the sulpholipids.     

Lipid and Fatty-acid Composition of Diatoms

The lipids and fatty acids of two freshwater diatoms Nitzschiapalea Kutz, Navicula muralis Lewin, and one marine species,Navicula incerta Grun. have been studied. The major lipid components in all species were triglycerides,monogalactosyl, digalactosyl and sulphoquinovosyl diglycerides,phosphatidyl glycerol, phosphatidyl choline (lecithin), andphosphatidyl ethanolamine; while palmitoleic, palmitic, eicosapentaenoicand eicosate-traenoic acids were the major fatty acid constituents.The two galactolipids, monogalactosyl and digalactosyl diglyceridescontained large amounts of C₁₆ and C₂₀ polyunsaturated fattyacids. Lipids of diatoms, whether grown in the light or in the dark,were the same apart from quantitative differences. More storagelipids such as triglycerides were synthesized in the light thanin the dark.     

Seed Lipids of the Grain Amaranths

The lipid and fatty acid composition of six members of two closelyrelated genera of the Amaranthaceae have been studied usinga combination of chromatographic procedures. The total lipidsvaried between 16.95 and 9.75% dry weight. Of these amounts,the non-polar lipids (mainly triglycerides) represented approximately90%, while polar lipids (glycolipids and phospholipids) accountedfor the remaining percentage. A relatively high degree of unsaturation was found for all lipidsdue to the dominance of linoleic acid (about 50%). The storage,metabolic, structural, and nutritional functions of the differentacyllipids are discussed.     

Studies on Fat Accumulation in Nitzschia palea Kutz

Fat accumulation in Nitzschia palea Kütz. starts perceptiblyat the end of the exponential phase of growth and reaches amaximum during the stationary phase of growth when the wholecell is filled with fat. Filtrates from old cultures enhancedfat synthesis probably by the production of an autotoxin whichinhibits cell growth but at the same time favours fat synthesis.The presence of an inhibitory autotoxin has not been provedbut indirect evidence suggests its presence. The nitrogen content of the culture medium also influences theamount of fat formed, more fat being accumulated in nitrogen-deficientmedia than in media provided with adequate nitrate supply. Theoptimum temperature for the growth of N. palea was found tobe about 30 °C while that for fat synthesis was around 35°C. Below 15 °C and above 40 °C, fat synthesis wasdrastically reduced. Blue and red light independently favoured fat synthesis whereasa combination of both did not. This is probably due to the selectiveinfluence of these wavelengths on the production of fat precursorsor intermediates.     

Physiological Studies on the Phospholipids of Diatoms

The four major phospholipids occurring in diatoms, viz. phosphatidylglycerol, phosphatidyl choline (lecithin), phosphatidyl ethanolamineand phosphatidyl inositol have been studied using radioactive³²P-orthophosphate. Kinetic experiments show that phospholipidformation followed two different biosynthetic patterns in thelight and in the dark. Phosphatidyl glycerol was predominantlysynthesized in the light, when it exhibited a fast rate of turnoverof label. On the other hand, phosphatidyl ethanolamine appearedto be light-inhibited, and accumulated more in the dark. Cultures bubbled independently with oxygen-free nitrogen andCO₂-free air and incubated in the light, showed more incorporationof radioactive orthophosphate into phospholipids than similarcultures bubbled with 3 per cent CO₂ in air. Cells starved ofcarbon and phosphate appeared to utilize labelled phosphateintermediates and their phospholipid reserves as sources ofthese material respectively. DCMU (10^–6 M) and DNP (10^–4M) appreciably reduced the amount of ³²P incorporated into phospholipids.In the absence of CO₂, the inhibitor, DCMTJ did not effectivelyreduce the incorporation of ³²P into phospholipids. It is suggestedthat photosystem I plays a dominant role in phospholipid synthesis.     

Lipid Composition and the Role of the Haustorium in the Young Seedling of the West African Oil Palm, Elaeis guineensis Jacq.

The lipid and fatty acid composition of the haustorium of thedeveloping seedling of the West African oil palm, Elaeis guineensisJacq. has been studied using the combined techniques of thin-layerand gas-liquid chromatography. In addition to triglycerides,which represented over 75 per cent of the total lipids, therewere present small quantities of free fatty acids, diglyceridesand polar lipids. The two glycolipids, monogalactosyl and digalactosyldiglycerides, formed the bulk of the polar lipids with smallamounts of phosphatidyl choline and phosphatidyl inositol. In general, the fatty acid pattern of the haustorium was intermediatebetween that of the palm kernel oil and the palm fruit mesocarp,and resembled to a great extent the fatty acids of the kerneltesta. It is suggested, from the presence of the biological membranelipids and lipolytic enzymes, that the main function of thehaustorium is that of food mobilization and transport for theyoung plant.     

Lipase Activity in Germinating Seedlings of Cucumeropsis edulis

Acetone powders prepared from dormant and germinating seedlingsof Cucumeropsis edulis contained an active lipase system whichshowed increasing lipase activity with germination. Kineticproperties indicated maximum activity at pH 5 and at a temperatureof 37 ° C, and the enzyme exhibited a zero-order reactionrate for the first 2 h of hydrolysis. The results obtained showedthat the enzyme is non-specific in its mode of action, hydrolysingfatty acids irrespective of chain length, degree of unsaturation,and the position of fatty acids in the triglycerides. The deterioration and spoilage of ‘ground’ seedsin storage has been shown to be due to the release of endogenouslipase during grinding. The release of lipase is greater thegreater the water content of the seeds     

Breeding for Short-stemmed Oil Palm in Nigeria: Fatty Acids, their Significance and Characteristics

The fatty acids of the progenies arising from the first back-crossfrom Elaeis guineensis and Elaeis oleifera interspecific hybridsto E. guineensis have been characterized. Fatty-acid patternsshowed striking variability which indicated that factors governingfatty-acid inheritance are polygenic. Although segregation forindividual fatty acids had no relationship with the large numberof morphological characters observed, a definite upward trendin the percentage of unsaturated fatty acids was clearly showncompared to the parent palms. The commercial and domestic advantagesof unsaturated fatty acids are discussed. Elaeis guineensis, oil palm, breeding, fatty acid content     

Palmae Lipids: Status in Chemotaxonomy

The lipids and fatty acids from the fruit-coats, pollens, andseeds of a number of palm species belonging to seven subfamilieswere characterized and used to evaluate the taxonomic positionof the Palmae. Fruit-coat and pollen lipids gave no definitepatterns and therefore did not offer data for taxonomic considerations.The seed lipids, on the other hand, showed remarkable persistencefor fatty acids in a number of the subfamilies. Contrary toestablished belief, lauric and myristic acids were not the principalfatty acids in all groups. The amount of these acids dependedon the gross anatomy of the seed.