Category Archives: 1991 Vol 3 No 2

A non-destructive quantitative method for the assessment of infection of oil palms by Fusarium oxysporum f. sp elaeidis

A non-destructive technique, involving removal of cylinders from stems with an auger, is described for the quantification of disease in mature oil palms infected with Fusarium wilt. Reisolation from cores confirmed that discoloration of vascular tissue is diagnostic for Fusarium wilt.
Good agreement was obtained between disease assessment based upon leaf symptoms and this new technique. Auger sampling was the more sensitive method and in some crosses revealed 50% infection in otherwise symptomless palms. The absence of the pathogen in older ‘resistant’ palms indicated that they were truly resistant and not tolerant to the disease.
High levels of vascular occlusion occur in diseased palm trunks but not in roots, which suggests that blockage of the trunk xylem system is the critical phase in symptom development.
Auger sampling in Malaysia failed to reveal the presence of the fungus inside palm trunks.
It is suggested that this technique could be useful in breeding programmes to identify resistant palms and reduce the risk of collecting seed from infected but symptomless palms. Other uses for the auger are also described.

Age-related changes in stomatal and photosynthetic characteristics of leaves of oil palm (Elaeis guineensis Jacq.)

Leaves from palms of different ages were examined for stomatal distribution, stomatal density, conductance to water vapour, and photosynthetic properties. Leaflets of mature (c. 12-year old) palms had stomata predominantly on the lower (abaxial) surface with few, if any, on the upper (adaxial) surface. Adaxial stomata were more evident in young palms (up to the first year after field planting).
Stomatal density (defined as total number of stomata per unit leaf area) increased progressively with age up to the second year in the field. Leaf conductance and photosynthesis rates, although very dependent on environmental factors, also increased with age, most markedly during the time of first fruit maturation. Photochemical efficiency increased with age of palm in parallel with increases in maximum rate of photosynthesis, while other photosynthetic characteristics either changed little (viz. carboxylation efficiency, photorespiration) or varied more with long term light environment (light compensation point, dark respiration rate) than with palm age.
The involvement of various factors in the increased photosynthetic capacity, and its significance for palm productivity and progeny selection, are discussed.

Isozyme analysis of plantlets from seven clones of oil palm (Elaeis guineensis Jacq.)

Starch gel electrophoresis of shoot extracts from plantlets of seven clones of oil palm (Elaeis guineensis Jacq.) was carried out and 12 enzyme systems were examined. Polymorphisms were detected for glutamate-oxaloacetate-transaminase(GOT),isocitrate dehydrogenase(IDH), leucine amino-peptidase (LAP), phosphohexose isomerase (PHI) and shikimate dehydrogenase (SHDH). Within clones, no differences could be detected. Using GOT, IDH, and SHDH as genetic markers, five of the clones could be differentiated, with the remaining two clones showing no isozyme differences between them.

Field evaluation of insecticides and a cultural practice against the bunch moth Tirathaba rufivena (Lepidoptera:Pyralidae) in a mature oil palm plantation

A field evaluation of a number of insecticides against Tirathaba rufivena was undertaken in a mature oil palm plantation at Teluk Intan between April and October 1988 over an area of 6.5 hectares.
The insecticides evaluated were endosulfan, diflubenzuron, cyfluthrin and Bacillus thuringiensis Berliner (Thuricide). The insecticides were applied three times at fortnightly intervals. Experimental controls were set up a) with no chemical treatment and b) using a cultural practice to maintain good sanitation.
The effects of treatments on the infestation of bunches and the larval density of the bunch moth were evaluated. Bacillus thuringiensis, cyfluthrin and diflubenzuron were more effective than endosulfan in the control of bunch moth. The cheapest treatment was B. thuringiensis, followed by cylfluthrin. The cost of using diflubenzuron was 2.5 times more than that of B. thuringiensis. Although cultural control could not be proven effective, it brought about some reduction in pest population and bunch damage and would also be expected to improve the efficiency of spraying insecticides.

Phospholipids and glycolipids in the oil from some varieties of Elaeis guineensis in India

The phospholipid and glycolipid compositions of oil from two varieties of the oil palm, Elaeis guineensis, namely dura and pisifera, are reported. The oil was extracted from mesocarp with chloroform-methanol (2:1, v/v) and the total phospholipids and total glycolipids were isolated from it by silicic acid column chronmtography using chloroform, methanol and acetone as the eluting solvents. The individual components of total phospholipids were identified after thin layer chromatography by comparison with authentic standards and using specific spray reagents. The mqior components were found to be phosphatidyl choline PC, 34% to 35%, phosphatidyl ethanolamine PE, 22% to 26%, phosphatidyl inositol PI, 21% to 25%, cardiolipin CL, 7% to 8%, phosphatidyl glycerol PG, 5% to 7%, and unidentified substances 4% to 6 per cent. The predominant fatty acids in all these components were palmitic, stearic, oleic and linoleic acids.
Thin layer chromatography revealed that the major components of total glycolipids were monoglycosyl diglyceride (MGDG), 22% to 25% diglycosyl diglyceride (DGDG), 42% to 45%, steryl glycoside (SG)13% to 14% and acylated steryl glycoside (ASG) 14% to 15%, with, unidentified substances making up to 2% to 9 percent. The predominant fatty acids of the glycolipids were palmitic, stearic, oleic, linoleic and linolenic acids. The SG and ASG fractions showed the presence of β-sitosterol, stigmasterol, campesterol and brassicasterol; β-sitosterol being the major component. For SG the ratio of sugar:sterol was 1:1 and for ASG the ratio of sugar:sterol:fatty acids was 1:1:1.

Quantitative analysis of carotenes in the oil from different palm species

Carotenes in palm oils from Elaeis guineensisdura (D), pisifera (P) and tenera (T), Elaeis oleifera or melanococca (M), from the hybrids M x D and M x P and from the backeross MP x D were analysed using HPLC and UV-Visible spectrophotometry. Eleven types of carotenes were identified, the major ones being α- and β-carotenes, which constituted about 90% of the total carotenes. Oil from E. oleifera (originally from South America) had the highest carotene content (4000 p.p.m.), while that from Elaeis guineensis (from West Africa) had the lowest (380 p.p.m.); their hybrids and the backcross had intermediate carotene contents.

Palm Oil Abstracts

This arti­cle com­piles abstracts of arti­cles and papers related to palm oil/ oil palm and other oils and fats, pub­lished in jour­nals, books and con­fer­ence proceedings.