Category Archives: 2012 Vol 24 Apr

Effects of neonicotinoid and method of breaking dormancy on seed germination and seedling vigour of oil palm (Elaeis guineensis Jacq.)

The effects of two neonicotinoids at three application rates (0, 2.5 and 5.0 ml kg-1 seed for thiamethoxam, and 0, 2.0, 4.0 g kg-1 seed for imidacloprid) and two methods of breaking dormancy (dry heat treatment and operculum removal) on seed germination and seedling vigour were determined in tenera oil palm seeds. The results reveal that the seeds with operculum removed took a shorter time to germinate than the dry-heated seeds, regardless of the neonicotinoid treatments. Thiamethoxam and imidacloprid had no promoting effects on seed germination or on time to 50% germination (T50). In this study, phytotoxicity effects were observed with the neonicotinoid treatments in the operculum-removed seeds in terms of the percentage of seeds producing shoots and roots as compared to the normal seedlings (control); such effects were not found in the dry-heated seeds.

A rapid and sensitive in situ RNA hybridisation method for oil palm tissues

We report here an in situ RNA (ribonucleic acid) hybridisation protocol with modified post-hybridisation procedures tested on tissues from two plants, oil palm and Arabidopsis thaliana. This protocol involves shorter post-hybridisation washes with SDS (sodium dodecyl sulphate) buffers, replacing the standard SSC (sodium chloride-sodium acetate-sodium citrate) and formamide buffers. This modified protocol was tested with a few genes, and contrary to the results from previously used protocols, clearer distinguishable signals were detected with antisense probes compared with the sense probes on hybridised tissue sections. The protocol also reduces the time taken by the previous standard protocol by approximately 6 hr and uses fewer reagents, thus saving time as well as costs.

Dispersion of the bagworms Pteroma pendula and Metisa plana in oil palm

An attempt was made to determine optimum sampling unit of between-palm and within-palm distribution of bagworms and their interspecific association distribution in oil palm using aggregation indices or distribution models. The within-frond distribution of bagworms varied significantly within the oil palm crown. Peak bagworm density was recorded between frond numbers 9 and 19. Through polynomial regression, standardised residual and relative net precision analyses, frond number 17 was established as the representative sampling unit for experimental work, and frond numbers 10-19 should be used when a greater precision is required as in life-table construction. A lack of interspecific association suggested these sampling units to be applicable for single and mixed infestations. Evaluation of between-palm dispersion revealed that Taylor’s Power Law gave a more appropriate fit with highly significant r2 values for all categories of assessment. The bagworms were regularly dispersed in oil palm with a general mean-variance relationship of log (s2) = 1.780 + 0.821 log (x¯).

Determining the optimal concentration of mannose as an effective selection agent for transformed oil palm cells using the phosphomannose isomerase (pmi) gene as a positive selectable marker

The elimination of antibiotic or herbicide resistance gene usage in genetically modified plants is being encouraged due to public concern. In response to this, alternative selection systems for the recovery of transgenic oil palm were developed using positive selectable markers. To establish a selection system that utilises the phosphomannose isomerase (pmi) gene for oil palm transformation, we first determined the optimal mannose concentration for selecting the transformed cells. Non-transformed embryogenic calli were cultured on media containing various combinations and concentrations of mannose and a usable source of carbon, i.e. sucrose, ranging in content from 0 to 30 g litre-1. Sucrose is often used as a carbon source in plant tissue culture media. The embryogenic calli were subcultured onto similar fresh media every four weeks, and growth was recorded monthly up to five months. From the 10 combinations of mannose and sucrose evaluated, mannose:sucrose at 30:0 g litre-1 was shown to be the most effective for selection because at this concentration the least plant growth was demonstrated for non-transformed embryogenic calli. We will thereafter use this particular concentration of mannose to select for oil palm embryogenic calli transformed with the pmi gene using biolistic bombardment.

Dielectric behaviour of polyurethane coatings derived from palm oil oleic acid-based polyols – a renewable resource

Dielectric relaxation spectroscopy (frequency range from 100 Hz to 40 MHz) was used to examine molecular motion in polyurethane (PUR) derived from palm oil oleic acid-based polyols at room temperature. PUR was prepared by varying the oleic acid content in the polyol (28%, 40% and 65%), while the NCO/OH ratio of PUR was varied to 1.2, 1.4 and 1.6. The effect of chemical contribution on dielectric behaviour of the samples was described. Dielectric parameters were in the range of 2.0 to 3.0 for real permittivity ε’ and 0.02 to 0.08 for imaginary permittivity, ε”. A Cole-Cole plot was fitted using the Havriliak-Negami model, and curve-fitting simulations were performed using Origin software program. A g-relaxation process was proposed as the probable mechanism for the dielectric behaviour of PUR. The dielectric constant and loss mechanism of the material were dependent on the NCO/OH ratio and the percentage of oleic acid content in the polyols used in synthesising PUR. The frequency-dependent conductivity of PUR materials was analysed using a Jonscher’s power-law expression, and the plot exhibited a DC plateau and a frequency-dependent region.

Swelling and dissolution of oil palm biomass in ionic liquids

Malaysia is amongst the world’s top producers of palm oil and the current planted area is around 4.5 million hectares. The palm oil industry generates vast amounts of palm biomass, especially empty fruit bunches (EFB) (from the mills), oil palm fronds (OPF) and oil palm trunks (OPT) (during routine pruning and from the field during replanting). Oil palm biomass can be used efficiently after further treatment, either by physical or chemical means. In this study, the swelling and dissolution mechanisms of the lignocellulosic biomass by ionic liquids were compared. There are five modes in describing the swelling and dissolution for cotton and wood cellulose fibre, and these were compared to the results obtained. Depending on the quality of the solvent, disintegration into rod-like fragments and ballooning, followed subsequently by dissolution were all observed among the oil palm fibre. In a typical dissolution trial, 5 wt % of oil palm biomass and cellulose fibre from EFB, OPF and OPT were treated with two different ionic liquids: 1-butyl-3-methylimidazolium chloride/dimethyl sulphoxide ([bmim]Cl)/DMSO and 1-ethyl-3-methylimidazolium chloride/dimethyl sulphoxide ([emim]Cl)/DMSO at a ratio of 80:20 wt %. They were heated at different fixed times, namely 4, 6, 8, 16 and 24 hr for untreated oil palm biomass, and 1, 2 and 3 hr for cellulose fibre. The mechanisms of swelling and dissolution were monitored by optical microscopy.

Avian biodiversity and conservation in Malaysian oil palm production areas

Our study demonstrated the persistence of avian biodiversity in established oil palm production areas. Here, the empirical evidence on avian species richness reflects explicitly that oil palm production areas are not merely a ‘green biological desert’. We investigated the relationships between bird species richness and different management regimes (plantations vs. smallholdings) and vegetation characteristics in 30 oil palm areas in the states of Selangor, Perak, Negeri Sembilan and Pahang. We recorded 72 bird species, comprising approximately 32% forest-dependent, 19% migratory and 10% wetland species. Our study showed that plantations and smallholdings supported a similar total number of bird species richness (P = 0.709). However, we found that a greater height of the ground vegetation cover had a positive effect on total species richness (P < 0.001). Similarly, there was no significant difference between plantations and smallholdings with respect to the total number of migratory species (P = 0.322). This number also increased when ground vegetation cover was higher (P = 0.010). We recommend the following appropriate conservation measures that may enhance avian biodiversity in oil palm production areas: (1) implementation of tree planting projects that benefit wild birds, (2) integration of oil palm with livestock grazing to phase out dangerous agrochemicals that are harmful to wild birds, and (3) continued promotion of ground vegetation cover to increase habitat heterogeneity on a local scale. Potentially oil palm can move towards becoming a sustainable and profitable commodity if production areas can be managed for conservation outcomes.

Zinc glycerolte: potential active for topical application

Crystalline metal-based glycerol complexes, such zinc (Zn), cobalt (Co), iron (Fe), nickel (Ni) and manganese (Mn) complexes, are formed by heating certain metal oxides, hydroxides or salts with glycerol at temperatures above 110°C. In this study, zinc glycerolate were synthesised using zinc oxide and excess glycerol at 240°C. The characterisations done were Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TGA-DTA), scanning electron microscopy (SEM), X-ray diffraction, in vitro dermal irritection assay and determination of sun protection factor (SPF). The hydrolysis property of zinc glycerolate in aqueous condition was also investigated. The hydrolysis of zinc ions followed a rather simple path unlike in the case of most polyvalent cations. The reaction of Zn2+ with OH ions resulted first in the formation of Zn(OH)+ species followed by precipitation of zinc hydroxide which easily redissolved in an excess of base to form a soluble complex. Quantitative TGA-DTA analysis was used to determine the amount of glycerol required in aqueous solution that could presumably minimise the hydrolysis of zinc glycerolate. Aqueous solutions that were subjected to high heat needed up to 60% of glycerol in order to preserve the zinc glycerolate. Therefore based on this study, zinc glycerolate is more suited to be incorporated in dry or anhydrous formulations such as powders and ointments. It has SPF of 1.07 ± 0.004 and ultraviolet A (UVA) ratio of 0.29, which is a moderate (one star) Boots star rating for UVA protection. Zinc glycerolate is classified as non-irritant, and therefore has good potential for use in the pharmaceutical and personal care product industries.

Optimisation of 2-deoxyglucose concentration for identifying the sensitivity level for oil palm embryogenetic calli

In this study, the sensitivity of oil palm calli to 2-deoxyglucose (2-DOG) was evaluated to determine the optimal concentration to be used as a selection agent for oil palm embryogenic calli. It was reported earlier that 2-DOG has been used for selecting transformants using the DOGR1 gene which encodes 2-deoxyglucose-6-phosphate (2-DOG-6-P) phosphatase. In plants, 2-DOG is converted into 2-DOG-6-P by endogenous hexokinase which results in the inhibition of cell growth. Therefore, an experiment to determine the optimal concentration of 2-DOG required to fully inhibit the regeneration of untransformed oil palm embryogenic calli was carried out. The untransformed embryogenic calli were cultured on embryogenic callus (EC) medium supplemented with different concentrations of 2-DOG, ranging from 0 to 1000 mg litre-1. Results show that 400 mg litre-1 of 2-DOG led to nearly complete inhibition (>80%) of oil palm embryogenic calli regeneration. This was demonstrated by a reduction in the calli weight and in the ability to form whitish embryoids. This optimal concentration of 2-DOG is recommended to be used for the selection and regeneration of transformed oil palm embryogenic calli after transformation using the DOGR1 gene in future experiments.

Determination of λ-cyhalothrin in palm and oalm kernel oil using tandem solid-phase extraction cartridges

This article outlines a new method based on low-temperature fat precipitation extraction with acetonitrile and graphitised carbon black/primary secondary amine (GCB/PSA) solid-phase extraction clean-up for the extraction of λ-cyhalothrin residue in both crude palm oil (CPO) and crude palm kernel oil (CPKO). Determination of λ-cyhalothrin was then carried out using gas chromatography (GC) equipped with an electron capture detector (ECD). Analyses for λ-cyhalothrin in palm oil and palm kernel oil samples spiked with different levels of λ-cyhalothrin (0.05, 0.08, 0.1, 0.5, and 1.0μg g-1) were performed. Mean recoveries for six replicates ranged from 82% to 98% for CPO and from 86% to 94% for CPKO, with relative standard deviation (RSD) values of less than 10% in most cases. The limit of detection for λ-cyhalothrin in both CPO and CPKO was 0.05 µg g-1. The method was successfully applied to the analysis of λ-cyhalothrin in CPO samples obtained from local palm oil mills throughout Malaysia. No λ-cyhalothrin was found in the 30 samples analysed.

Properties of residual palm pressed fibre oil

Residual fibre oil was recovered from palm pressed fibre by using a solvent (hexane). The oil was analysed for its physical and chemical properties. The macro-nutrient and element contents of the pressed afibre were also analysed. The residual fibre oil co ntained high amounts of phosphorus (144 ppm), vitamin E (1153 ppm) and carotenes (1877 ppm). The compositional content of vitamin E present was 54.0% α-tocopherol, 19.2% α-tocotrienol, 16.7% α-tocotrienol and 10.1% α-tocotrienol. The major fatty acids of t he residual fibre oil were palmitic and oleic acid at 31.9% and 24.8%, respectively. The oil also contained a high amount of lauric acid (22.0%) which is the major fatty acid in palm kernel oil. Density of the residual fibre oil as a function of temperature was measured at temperatures ranging from 40°C to 75°C. Density exhibited a linear relationship with temperature. Viscosity of the residual fibre oil was shown to decrease with an increase in temperature. The formation of needle-shaped crystals was observed when the residual oil was cooled down from 36°C to 34°C. There were no significant changes in the macro-nutrient and element contents of the palm pressed fibre before and after oil extraction with hexane.

Analysis of oil palm calli and regenerants using flow and image cytometry and 18S-25S ribosomal DNA fluorescence in situ hybridisation (FISH)

Flow (FCM) and image cytometry (ICM) and 18S-25S ribosomal DNA (rDNA) fluorescence in situ hybridisation (FISH) were used to analyse the genetic stability or variation in oil palm in vitro plantlets, various forms of calli, and slow- and fast-growing liquid suspension cultures. Both FCM and ICM results show a similar correlation pattern where samples with lower DNA content had lower integrative optical density (IOD) peaks. The 18S-25S rDNA FISH showed two large signals in the interphase cells of calli analysed, indicating a diploid ploidy level. Significant differences were observed in the DNA content and pattern of nuclei activity of the slow- and fast-growing liquid suspension cultures using FCM and ICM analysis, demonstrating the usefulness of the above-mentioned tools developed to analyse materials prior to micropropagation; hence, the oil palm’s clonal fidelity is ensured, and the efficiency and robustness of liquid culture are improved by selecting callus materials which have similar DNA content and IOD range and peak as the fast-growing friable suspension and friable calli used in this study.

A time course anatomical analysis of callogenesis from young leaf explants of oil palm (Elaeis guineensis Jacq.)

Histological and scanning electron microscopy analyses were employed to analyse callus development in oil palm at fortnightly intervals over a period of 28 weeks. The emergence of primary calli on the surface of the oil palm leaf explants was generally observed after 10 weeks of culture. Callus initiation was detected earlier, at six weeks, upon the division of perivascular cells within the leaf explant. This is the first report documenting the presence of a net-like structure termed as an extracellular matrix surface network (ECMSN) on the callus surface and the epidermal layer of the leaf explants of oil palm. We also observed peculiar ‘empty’ epidermal cells and small spherical particles on the surface of the epidermal cells of the leaf explants concomitant with the formation of a callus that have not been reported during callus initiation in other plants. These results may provide basic knowledge and facilitate our understanding of the biological processes involved during oil palm callogenesis. The anatomical changes and the presence of unique features like ECMSN may act as structural markers during callogenesis of oil palm.