Category Archives: 2001 Vol 13 No 1

Effects of metsulfuron-methyl on ALS activity and its metabolism in immature oil palm

The effects of metsulfuron-methyl on injury and acetolactate synthase (ALS) activity were measured in immature oil plam seedlings under greenhouse conditions. Metsulfuron-methyl sprayed directly onto seedlings caused a whole range of injuries to the 18-month-old palm seedlings, but its residue in soil did not affect seedling growth. Chlorosis appeared three weeks after treatment (WAT). The percentage of injury score was found to increase proportionally with herbicide dosage. Metsulfuron-methyl inhibited ALS enzyme in the seedlings. Metsulfuron-methyl at 41nM could inhibit 50% activity (I50) of ALS enzyme. Metsulfuron-methyl compound was metabolized to seven metabolities, of which two could not be identified

Genotype x environment interaction and stability analyses in oil palm (Elaeis guineensis Jacq.) progenies over six locations

Genotype and environment (G x E) interaction was estimated in 40 oil palm dura x pisifera progenies, evaluated at six locations for yield and its components. The presence of G x E interaction was detected for yield and its components. The G x E variance component was relatively small and ranged from 3.53% to 4.12%. The result showed that fresh fruit bunch (FFB) yield had a larger G x E variance component (σ2gl) than genetic variance component ( σ2gl), indicating that this character was very sensitive to the environment. The joint regression analysis showed that the linear regressions accounted for a small proportion of the total G x E interaction. This suggests that a non-linear component part of G x E interaction for the characters played an important role.
The combined use of all the stability determination methods could provide a better interpretation of individual stability of genotypes. Combined use of 10 stability statistics for FFB yield indicated that progenies DP8 and DP21 were highly stable genotypes, which also produced above average FFB yield. On the other hand, progenies DP7 and DP30 were the most unstable genotypes as indicated by all the stability parameters

Effects of Azospirillum inoculation on N2 fixation and growth of oil palm plantlets at nursery stage

Nitrogen fertilizer is the most expensive nutrient input in oil palm production, with an average total nitrogen fertilizer cost estimated at RM 470 million yr-1. The use of nitrogen ftxing bacteria (e.g. Azospirillumspp.) as a biofertilizer and bioenhancer can reduce the production cost of this crop. A glasshouse experiment was undertaken to observe the effects of Azospirillum inoculation on N2fixation, plant growth and photosynthetic rate of the host plant. This experiment was conducted in undrained pots with 15N labelled Selangor series soil and each pot was planted with a two-month-old oil palm plantlet (MPOB clone, P149). Three treatments were applied: 1) control [+ killed inoculum (Sp7)], 2) Azospirillum brasilense (Sp7) inoculation and 3) A. lipoferum (CCM 3863) inoculation. This experiment was laid out in a randomized complete block design with four replications and harvested four months after planting. Two weeks before harvest, the first fully expanded leaf from each seedling was analysed for light and CO2 response using a closed system of portable infra-red gas analyser. At harvest, the plantlets were separated into tops and roots, dried, weighed and ground for total nitrogen and 15N analyses. Results showed that Azospirillum inoculation contributed up to 40% of the total nitrogen requirement of the oil palm plantlets, stimulated top and root growth by 30% and 60%, respectively and increased the host photosynthetic rates compared to the control. Azospirillum (Sp7 and CCM 3863) is a potential biofertilizer and bioenhancer for sustainable oil palm plantlet cultivation and saves cost on nitrogen fertilizer.

Selectivity and kinetics of interesterification reaction of glucose pentaacetate with fatty acid methyl esters

Acetylated glucose fatty esters (AGFEs) were prepared by a solvent-free interesterification reaction of glucose pentaacetate (GPA) and mixed fatty acid methyl ester (FAME) of palm oil (PO)-based fatty acids. The relative selectivity of fatty acyl groups towards the GPA ring and the kinetics of the interesterification process were studied. The selectivity studies have shown that the longer chain fatty acyl groups were preferred in the interesterification process involving GPA and FAMEs. In the C6 to Cl0 fatty acids group C l0 was the most favoured, while C18:1 had the highest selectivity in the C12 to C18:2group. The results also showed that the reactions involving oleic-FAME and C6-10-FAME proceeded via zero-order kinetics with respect to GPA

Physical mapping of rRNA genes on Elaeis chromosomes

Physical mapping of rRNA genes by in situ hybridization was performed on Elaeis species chromosomes. Fluorescence in situ hybridization (FISH) was perforrned on Elaeis oleiferachromosomes with probe pBG35 which contains 18S-25S rRNA genes from flax. Hybridization sites were located on the telomeric regions of an acrocentric pair of chromosomes and their satellite DNAs. Multiple labelling FISH was used to physically map the 5S and 18S-5.8S-25S rRNA multigene family in the interspecific hybrid of E.oleifera x Elaeis guineensis (OxG). Two heterologous labelled probes with 18S-25S (pTa 71) and 5S (pTa 794) rDNA were used for in situ hybridization of these chromosomes. It was found that 5S genes are situated on the proximal arms of the longest chromosome pair, or pair No. 1. The 18S-5.8S-25S rRNA genes are located on the telomeric regions of an acrocentric pair of chromosomes and on the satellite DNAs. The technique can now be used to locate other sequences of interest in the Elaeis species

Factors affecting development of Oryctes rhinoceros in some substrates commonly found in the oil palm environment

A laboratory study was conducted to evaluate the factors which affected larval development in four different substrates commonly found in the oil palm replanting environment. The percent survivorship of Oryctes rhinoceros was lowest in raw empty fruit bunches (EFB), followed by coconut trunk (CT) and oil palm trunk (OPT). Processed EFB and oil palm fronds (OPF) were found to be less suitable substrates, as indicated by the incomplete development of the larval stages. There were lower percentage of nitrogen in the OPF (0.45%) and EFB (0.35%), compared to CT (1.98%) and OPT (0.56%) substrates, which could have affected the duration for each developing stage. The higher starch content in OPT compared to raw EFB may also have influenced the development of the larvae. The weights of almost all the developing stages were higher in CT substrate. The second and third larval instars had consumption rates of 2.2 g day-1 and 4.1 g day-1 of CT and OPT substrates respectively. Although the consumption rates were higher in OPT, the weight of larvae remained significantly lower (p<0.05) than in CT. There was a significant linear relationship (p<0.001) between the percent moisture content and weight of the third instar larvae, showing water to be an important factor in ensuring weight increase in the larval and subsequently, pupal stages. Moisture content of 77% and above was essential for the complete development of 0. rhinoceros. It is hoped that this information will lead to a modification of the zero burn replanting practice, so as to create less suitable environments for the beetle to breed in, thus avoiding the risk of 0. rhinoceros attack.

Surface tension, foaming and detergency properties of mixed alpha-sulphonated methyl esters derived from palm stearin with some commercial surfactants

The effects of sodium alpha-sulphonated methyl esters derived from palm stearin salt (α-SMEPS) and commercial surfactants (CS) in mixed micelle systems were studied as a function of their weight ratios. Changes in the surface tension were observed as the different weight ratios of the mixed surfactants. Only the α-SMEPS:AE-3EO system reduced the surface tension of α-SMEPS solution. Incorporation of a commercial surfactant into a solution of α-SMEPS also changed its foaming properties (foaming power and foam stability) and washing performance. No synergy was observed in dish washing performance. However, synergy effect on cloth washing was exhibited by α-SMEPS:AE-3EO, α-SMEPS:SLES-2EO and α-SMEPS: ALS systems.

Response of oil palm progenies to different fertilizer rates

Ninety-nine dura x pisifera progenies (genotypes) from six seed producers (populations) in Malaysia were subjected to three fertilizer treatments after field planting in 1983. The fertilizer treatments were half, normal and twice the standard estate rate. Yield recordings and bunch analyses were taken between 1987 and 1998. Analyses of variance (ANOVA) for fresh fruit bunch (FFB), bunch number (BNO) and average bunch weight (ABW) showed significant differences for fertilizers, populations and genotypes. In addition, FFB differed significantly for genotype x fertilizer (GxF) interaction. Generally, FFB would increase at twice the estate fertilizer rate, but reducing the normal rate to half did not reduce the yield significantly. Despite improvements in ABW, reduction in FFB was due to lowering of BNO. Conversely, an increase over the standard fertilizer rate did not affect BNO. Populations 4 and 2 were high in FFB due to higher BNO and higher ABW, respectively. Progenies 4062, 4056 and 6094 shared the highest yields at half, standard and twice the standard estate rate, respectively.
ANOVA for bunch quality components was carried out and significance was detected for the populations and genotypes. Variation between fertilizers was significant for mean fruit weight, oil to bunch and kernel yield (KPY). High values for these characters along with FFB were advantages in certain populations and genotypes for higher total economic product (TEP). Highest TEP within the normal fertilizer level was recorded in Population 3, and at the altered levels was Population 4. Progeny 4051 was outstanding for TEP at half the fertilizer rate, Progeny 4056 at normal level and Progeny 5073 at twice the estate standard rate. Populations 4 and 2 offered prospects for higher oil yields at half the fertilizer cost, while Population 5 might be advantageous in lauric oil production