Category Archives: 2013 Vol 25 Apr

Effects of temperature on the development and survival of the bagworms Pteroma pendula and Metisa plana (Lepidoptera: Psychidae)

The effects of temperature on the development and survival of Pteroma pendula and Metisa plana was investigated over a range of temperatures in the laboratory. Pteroma pendula and M. plana were able to complete their life cycles at temperatures between 20°C-35°C but did not survive at 15°C and 40°C. The duration of life stages of P. pendula significantly decreased with increases in temperature with optimum survival of between 25°C and 30°C, while the highest was at 30°C. In the case of M. plana, except for survivorship of male pupae with five instars at 79% at 25°C, the optimum survivorship was around 30°C for all other life stages. The temperature threshold for P. pendula life stages was 11°C-18°C, while that of M. plana ranged from 2°C-16°C; when subdivided, a threshold of 2°C-8°C was recorded for the egg to adult stages and 9°C-16°C for the egg and larval stages. Thermal constant for P. pendula was 80.3°d, 443.0°d, 566.3°d, 47.5°d, 33.9°d for eggs, female larvae, male larvae, female pupae and male pupae, respectively. Overall egg to female and male adult emergence required 544.0°d and 761.3°d to complete. For M. plana, the readings were 555°d-1083°d for the larval stages, 69°d-200°d for eggs and pupae, while the egg to adult stages recorded the highest at 1440°d-2134°d. Both species recorded significantly highest temperature of 30°C for adult female weight, fecundity and R0 with the most favourable values of T, DT, rc, rm and λ recorded at 35°C.

Candidate hormone-responsive markers for callogenesis of oil palm (Elaeis guineensis Jacq.)

The in vitro propagation of the oil palm involves an indirect somatic embryogenesis process through an intervening callogenesis phase. Both processes are determining factors in the success of clonal propagation. This study aims to discover expression markers associated with hormone response as a means to measure the favourable response of oil palms to callogenesis. Expression levels of hormone responsive genes in cultured and uncultured leaf explants were measured by using quantitative real time PCR, followed by statistical analysis to determine whether a relationship to callogenesis existed. The potential for callogenesis in cultured leaf explants of oil palms was significantly correlated to the expression changes of a putative brassinosteroid leucine-rich repeat (LRR) receptor kinase (EgBrRK), a putative cytokinin dehydrogenase (EgCKX) and a putative response regulator type A gene (EgRR1). A regression model for callogenesis incorporating these three genes indicated a predicted R2 value of 67.89%. The larger reduction in the expression of EgRR1 and another cytokinin responsive gene, EgCK REGULATED KINASE, in cultures exhibiting higher callogenesis rates suggested an increase in cytokinin signalling output and cytokinin levels. This inference was supported by a slight decrease in the expression of EgCKX, suggesting a mild reduction in cytokinin degradation in these cultures. The use of these markers for the prediction of callogenesis rate in uncultured and one-day cultured leaf explants, may provide an early assessment of the callogenesis potential of oil palms.

Speciality oleochemicals from palm oil via enzymatic synthesis

Palm-based specialty oleochemicals are special industrial chemicals from palm oil which are highly priced with high profit margins. These oleochemicals exhibit interesting properties such as excellent emolliency, surface activity, emulsifying properties as well as beneficial biological properties. As such, these compounds find many applications in the cosmetic, pharmaceutical and food industries. Enzyme catalysed syntheses of these chemicals are preferable as compared to their usual petro-chemical counterpart as these processes are nature identical and ‘green’. Lipase-catalysed syntheses of specialty oleochemicals were carried out. The oleochemicals include amino acid esters, fatty alkanolamides, fatty esteramines, various wax esters, medium chain triglycerides and biologically active esters. The optimisation of the reaction conditions was discussed. The effects of the parameters influencing the reactions including temperature, reaction time, substrate molar ratio, amount of enzyme and solvents used were presented. The characteristics of the reaction system and the products were determined

Gas chromatography-flame ionisation detector method for determination of carbon chain length distribution of palm-based fatty alcohol

A simple and rapid gas chromatography (GC) method using a flame ionisation detector (FID) was developed for the determination of the carbon chain length (CCL) distribution of palm-based fatty alcohols (FAL). The method involved a single-step sample preparation, where the FAL was silylated with N,O, -bis(trimethylsilyl)trifluoroacetamide with 1% trimethylsilyl chloride in N,N- dimethylformamide into trimethylsilyl ethers, followed by its direct injection into the GC-FID system. The precision and long-term precision of the GC-FID instrument performance was high as shown by coefficient of variation (CV) of lower than 1.00% (retention time) and 1.80% (peak areas) from multiple injections of three sets of FAL standards mixture (CCL ranging from C8 to C20) for three consecutive days. The results obtained for the CCL distribution (as relative percentage of peak area) for commercial FAL were close to the known values provided by the manufacturer, showing good accuracy of the method. The CV obtained from analyses of four replicates commercial FAL and its blends was lower than 1.5% indicating that the method has good repeatability.

Soil microbial and root respirations from three ecosystems in tropical peatland of Sarawak, Malaysia

The partitioning of soil respiration (SR) to root respiration (RR) and microbial respiration (MR) was conducted using the root exclusion and closed chamber method in three ecosystems on tropical peatlands. RR was estimated by differencing SR and MR. The forest ecosystem displayed significantly higher monthly MR compared with oil palm and sago ecosystems with the highest value of 219 mg CO2 C m-2 hr-1 in May 2003. This might be attributed to its thick leaf litter and root mat, and water filled pore space which was conducive for microbial activity. The lowest range of MR, between 153 mg CO2 C m-2 hr-1 (October) and 34 mg CO2 C m-2 hr-1 (September), was found in the sago ecosystem probably due to its high water-table. The highest RR was recorded in the forest (172 mg CO2 C m-2 hr-1), followed by oil palm (128 mg CO2 C m-2 hr-1) and sago (95 mg CO2 C m-2 hr-1). The latter might be ascribed to its slow growth rate, while the former to higher root biomass and growth rate. The annual ratio of RR to SR was 52% in the sago ecosystem and 60% to 62% in both oil palm and forest ecosystems.

Metabolite profiling of oil palm towards understanding basal stem rot (BSR) disease

Basal stem rot (BSR) which affects many oil palm plantations in Malaysia is a destructive disease caused by the wood decaying fungi Ganoderma boninense. Information on response of oil palm to BSR is scarce, particularly concerning changes in the level of plant metabolites as the ultimate consequence of biological systems to genetic or environmental changes. A previous study on root inoculation technique was conducted by MPOB to identify oil palm progenies partially tolerant and susceptible to G. boninense infection that causes BSR. Therefore, in this study, parental palms of these progenies were identified and root tissues of both partially tolerant and susceptible parental palms of different BSR susceptibility were used to analyse metabolites by using a metabolomic-based approach. In this report, we examine the application of liquid chromatography-mass spectrometry (LC-MS)-based metabolomics to study aqueous methanolic extracts of root tissues of selected parental palms that are partially tolerant and susceptible to G. boninense. Collectively, 39 peaks were observed from LC-MS analysis operated in negative mode and of these, nine distinctive peaks were further characterised using accurate mass, isotopic pattern, database match and MS/MS experiment for compound identification. Together with several other metabolites, MS/ MS spectrum of procyanidin B was presented and all the major fragments were assigned with predicted sub-structures. The nine metabolites which were also successfully identified revealed a range of plant sugar and phenolics derivatives in parental palms root extracts. The novelty of the technique relies on the use of mass signals and the analytical strategy that are applicable to a wide range of analysis in oil palm root metabolomics. These findings provide information on the relationship between phenolic compounds as marker metabolites for disease detection and oil palm preventive mechanism against BSR.

Identification of oil palm (Elaeis guineensis) spear leaf metabolites using mass spectrometry and neutral loss analysis

Plant metabolites characterisation is an arduous challenge due to their structural diversity as a result of complicated biosynthetic pathways. These metabolites are not only important for metabolic events description but are also harnessed as valuable nutraceuticals. The detection and description of important plant tissue metabolome such as oil palm spear leaf can be carried out using a broad-range, non-targeted analytical tool such as mass spectrometry (MS). Identification of oil palm spear leaf constituents such as carboxyl group- and sugar- containing metabolites was facilitated by tandem mass spectrometry (MS/ MS) with neutral loss information of 44 and 162 amu. A total of 13 metabolites ranging from carboxylic acids, catechins, phenolic acid glycosides and a stilbenoid were characterised in this manner and the results presented here demonstrated the usefulness of MS in characterising metabolites in a complex sample such as oil palm spear leaf tissue.

Determination of glufosinate ammonium in crude palm oil: use of the modified quechers method and LC-MS/MS detection

The herbicide, glufosinate ammonium is widely used as crop protection for food crops and also in oil palm plantations. The herbicide is used to control weeds and also as a dessicant agent for land clearing. In this work, glufosinate ammonium was extracted from crude palm oil (CPO) samples using a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method. This method was based on a simultaneous extraction and clean-up steps which required minimum sample handling. The extraction was performed using 5.0 ml deionised water, (0.1% formic acid) and dichloromethane. The glufosinate ammonium residue was extracted from CPO samples using a mini shaker and centrifuged for 10 min at 2500 rcf. The extracts, following pre-concentration were clean enough for direct injection into the LC-MS/ MS. Quantitative recoveries from 84%-109% were obtained for samples spiked with three concentration levels of 0.005, 0.05 and 0.5 μg ml-1. The correlation variation (CV) percentage for reproducibility and repeatability of replicate extractions were less than 13% and 10% respectively. The limit of detection and limit of quantification was 0.002 μg litre-1 and 0.025 μg kg-1 respectively. The results obtained demonstrated that the method has achieved the requirements of the criteria for acceptance of single laboratory method validation. Determination of glufosinate ammonium residues in Malaysian CPO samples were carried out and the residues were not detected in the analysed samples.

Synthesis of palm-based polyols: effect of K10 montmorillonite catalyst

Palm-based polyols were synthesised via an alcoholysis process using K10 montmorillonite catalyst. The alcoholysis process was carried out by using epoxidised palm olein and isobutanol. The catalysing ability of K10 montmorillonite catalyst during alcoholysis process was investigated. The process factors affecting alcoholysis, such as reaction temperature and reaction time, were studied. The optimum reaction conditions discovered of 60°C for 2 hr of reaction time were defined for production of palm-based polyol with optimised hydroxyl value, that is, 124.71 mg KOH g-1 of sample. Based on the study, K10 montmorillonite catalyst was able to catalyse the alcoholysis process to produce palm-based polyol with a low acid value, low viscosity, low average molecular weight distribution and low functionality which is suitable to be used as a component in coating applications.

Influence of indole-3-acetic acid (IAA) produced by diazotrophic bacteria on root development and growth of in vitro oil palm shoots (Elaeis guineensis Jacq.)

The interaction between plant and diazotrophs would influence the synthesis of phytohormone [indole-3- acetic acid (IAA)]. Generally, IAA excreted by the bacteria would increase top and root biomass and lateral root numbers of the host plants. Thus, the objectives of this study were to estimate IAA productivity of free-living diazotrophs and to observe the effects of IAA produced on root development and shoot growth of in vitro oil palm plantlets. Four diazotrophic bacteria used in the study, Herbaspirillum seropedicae (Z78), Microbacterium sp. (E7), Acetobacter sp. (E9) and Microbacterium sp. (E14) successfully produced IAA under free-living conditions. These diazotrophs exhibited optimum productivity of IAA during the log growth phase. Isolates of Microbacterium sp. E7 and E14 produced the higher concentration of IAA and also higher overall productivity of IAA compared to the other isolates tested. In order to observe plant growth-promoting effects of the phytohormones produced by the diazotroph, all the tested diazotrophs were inoculated onto the in vitro (tissue-cultured) oil palm shoots (Elaeis guineensis Jacq.). In associative conditions, inoculation of Z78 showed a significant increment in number of secondary roots, fresh weight, and protein content of oil palm shoots compared to those receiving control treatments. Significant responses of isolates E7 and E14 were also observed in the initiation of secondary roots, protein content and the increment of shoot fresh weight. This study concluded that IAA produced by Z78, E7 and E14 could contribute to enhanced growth and development of in vitro oil palm shoots and can be further developed into a potential biofertiliser.

Estimates of repeatability and path coefficient of bunch and fruit traits in Bang Boet dura oil palm

A study was conducted to estimate repeatability, minimum number of evaluations to which a trait should be subjected, and the inter-relationship of 19 traits related to bunch and fruit in Bang Boet dura oil palms. Repeatability values were found varying between 0.098 – 0.691. The optimum number of bunches for observation of bunch weight, fruit weight per bunch, stalk weight per bunch, number of fruits per bunch, weight of large size fruits, and number of large size fruits were three to six bunches, while the number to assess weight of small size fruits, weight of medium size fruits, number of medium size fruits and number of small size fruits were 7-11 bunches. The number of bunches for determing percentage of crude palm oil and palm kernel oil per bunch should be four and eight bunches, respectively, whereas the optimum number of fruits for observation of kernel thickness, fruit width, fruit length, weight per fruit, percentages of mesocarp, shell and kernel were four to nine fruits, and for endocarp and mesocarp thickness were 18- 22 fruits. High positive correlations were observed between bunch weight and fruit weight per bunch, bunch weight and stalk weight per bunch, fruit weight per bunch and weight of large size fruits, bunch weight and weight of large size fruits, and fruit weight per bunch and number of large size fruits, with the values of 0.98, 0.92, 0.91, 0.88 and 0.88, respectively. Path coefficient analysis showed that oil palm yield was directly influenced by bunch weight and number of bunches per plant. Oil palm bunch weight was determined mainly by fruit weight per bunch, which was directly affected by weight of large size fruits. High percentage of mesocarp per fruit influenced the percentage of oil per bunch. Oil palm breeders can apply this information to select for high yield through these yield components.

The development of a residual oil recovery system to increase the revenue of a palm oil mill

The Malaysian oil palm industry is an export orientated industry which heavily relies on the world market. The Malaysian oil palm industry has shown stellar performance in 2011. The average annual price of palm oil for the year 2011 breached the RM 3000 mark to register at RM 3219, while the export revenue of palm products reached a record high of RM 80.4 billion. Since the 1980s, the judicious utilisation of the various by-products through nutrient recycling in the fields has reduced environmental impact, thus paving the way towards a zero-waste policy. Crude palm oil (CPO) is produced in the palm oil mills by mechanically extracting it from the digested mesocarp of the palm fruits. Currently, mills uses screw presses for the oil extraction process. However, mechanical methods have their limitations, as some oil will still remain in the mesocarp, even after being subjected to high pressure mechanical squeezing in the screw presses. The pressed mesocarp fibre retains about 5.0%-11.0% oil expressed as a ratio to the dry matter. This translates into an oil loss per tonne of fresh fruit bunches (FFB) in the range of 0.25%-0.55%, at an average moisture content of 36% in the pressed mesocarp fibre. In order to recover part of this residual oil in the pressed mesocarp fibre, a residual oil recovery system (RORS) was developed. This system has the ability to recover the residual oil in the pressed mesocarp fibre by using a washing technique, followed by pressing to recover CPO. Water at a certain temperature is used to wash the pressed mesocarp fibre in the digester, following which the fibre is pressed in a screw press. The water and oil expelled by the pressing operation after channeling to a vibrating screen to filter out the solid tailings are directed to an oil recovery tank situated in the mill. The recovered oil is then fed into the clarification tank or the purifier tank while the water phase is either treated for recycling or disposed. The system is found to reduce the residual oil content in the pressed mesocarp fibre to as low as 2.0% on a dry basis. This translates into 0.72% on a wet basis. The normal oil loss in pressed mesocarp fibre in the mill is 5% to 11% on a dry basis (equivalent to 1.8% to 3.96% on a wet basis). The oil extracted by RORS also depends on the amount of oil loss, and will range from 3.0% to 9.0% on a dry basis, or 1.08%-3.24% on a wet basis. This translates into 0.15% to 0.45% oil recovery per tonne of FFB. CPO that is extracted from the pressed mesocarp fibre by RORS exhibits even better oil quality than the normal CPO.

Superior effect of compost derived from palm oil mill by-products as a replacement for inorganic fertilisers applied to oil palm

Trials by Sumatra Bioscience have shown that high quality compost can be produced by composting empty oil palm fruit bunches with oil mill effluent in an open windrow system over 25 days. Fifteen tonnes of the final product typically contains 105 kg N, 16 kg P, 168 kg K and 26 kg Mg, which is close to the average nutrient levels applied to oil palm in Sumatra as inorganic fertiliser per year, except for P which is lower in the compost. Thus, compost applied alone clearly has the potential to replace the inorganic fertilisers usually applied to oil palm. Two trials have been carried out to compare the effectiveness of compost and inorganic fertilisers applied to oil palm on a typical volcanic ash soil in North Sumatra and to determine the optimal rate and method of application of the compost.

The first trial tested a factorial combination of three rates of compost, urea, rock phosphate and muriate of potash. The highest rate of compost (10 t ha-1 yr-1) applied alone increased the FFB yield from 23.1 up to 26.8 t ha-1 yr-1 over a three-year period, which is an increase of 0.37 t ha1 yr-1 FFB per tonne of compost applied each year. A similar yield was achieved with 2 kg urea plus 1 kg rock phosphate (there was no response to K fertiliser), which based on the nutrient content of the two materials, indicates that the N and P in the compost were 66% and 37% more effective than the nutrients in the inorganic fertiliser (and confirms that the P content in the compost is more than adequate). The greater efficiency of compost compared to the inorganic fertilisers in supplying N and P to the oil palms was also confirmed by the higher recovery of these nutrients into the palm fronds. The highest yield of 28.7 t ha-1 yr-1 in this trial was achieved with 10 t ha-1 yr-1 compost plus 2 kg urea and 2 kg rock phosphate, indicating that if only compost is applied, the highest rate will be needed to achieve the optimal yield.

In the second trial, compost alone was tested at incremental rates of up to 20 t ha-1 yr-1, applied as a patch between the avenues and as 1, 2 and 3 m bands down the avenues. The optimal yield over three years was achieved with 15 t ha-1 yr-1 compost, which increased FFB production from 26.9 to 32.6 t ha-1 yr-1; which is an increase of 0.38 t ha-1 yr-1 FFB per tonne of compost applied per year and this is in very close agreement with the response recorded in the first trial.There were no significant differences due to the different methods of application of the compost. As in the first trial, N and P nutrient contents in the fronds were very significantly increased by the compost, but not K, due to a high K nutrient reserve level in the soil.

The cost of producing 1 t of compost by the windrow method and applying it in the field in Lonsum estates has been calculated as USD 10, so the application of 15 t ha-1 of compost in the second trial would cost USD 150. Application of inorganic fertilisers at the same nutrient rates as 15 t compost ha-1 yr-1 at 65% moisture content is approximately twice as expensive as compost. Taking into account the greater efficiency of compost in supplying nutrients, replacement of inorganic fertilisers with compost would save the costs of inorganic fertilisers almost three times as much. However in the trial area, K and Mg fertilisers were not required, so savings by switching to compost at this particular location would be less.

An anatomical comparison between bunch and fruit of oil palm with pineapple leaf and three woods from plantations in Costa Rica

Elaeis guineensis, Ananas comusus and forest plantations are planted widely in Costa Rica; however their residues (8000 t) are not utilised. The main objective of this work was to undertake an anatomical description of the structure of the oil palm’s empty fruit and the leaves from the crown and plant of the pineapple. Fibre dimensions of these agricultural crops were also compared with three main timber spe-cies planted. The anatomy of the fruit and the bunch of the oil palm are different from wood anatomy or pineapple leaves. The fibre dimensions and the anatomical distribution of the vascular strands are different for the pineapple leaf, the oil palm fruit and bunch . Large quantities of vascular strands are found in the oil palm bunch, and their frequency is similar in the oil palm fruit. A large proportion of parenchyma is observed in the pineapple leaf compared with the oil palm bunch and fruit. Oil palm fibre is different from the fibre dimension of the pineapple leaves and of wood. Wood and oil palm fruit and bunch present similar fibre dimensions. The pineapple leaf fibres are shorter fibres with wider diameter and thicker wall than oil palm and wood species.

The fate of diuron in soil in a Malaysian oil palm plantation

A field study on the leaching and persistence of herbicide diuron in an oil palm agro ecosystem was conducted in an oil palm plantation in Sepang, Selangor. Two treatments, namely the recommended and double the recommended dosage of diuron were applied in the field trial. Diuron was sprayed using a knapsack sprayer (18 litres) at the rate of 0.3 kg ha-1 (recommended dosage) and 0.6 kg ha-1 (double the recommended dosage). Soil samples were collected at different depths, viz. 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm and 40-50 cm at the following intervals: -1 day (before treatment), 0 day (day of treatment, 6 hr later), 1 day, 3, 5, 7, 14, 21, 30, 60, 90 and 120 days after treatment. Diuron residue was detected in the soil sampled at all depths, for both the dosages applied from day 0 to 60 days after treatment (DAT), with the exception of day 90 where it was only detected at the 0-10 cm depth when the plot was sprayed at double the recommended dosage. The calculated half-life of diuron when applied at both dosages was also determined and results showed that the half-life of diuron in soil when applied at the recommended and double the recommended dosage was in the range of 22.35 – 49.5 days and 18.73 – 57.75 days, respectively.