Hevea brasiliensis Research Papers - Academia.edu (original) (raw)

Rubber wood (Hevea brasiliensis) esteri®ed with acetic anhydride, maleic anhydride and phthalic anhydride was studied for moisture adsorption behaviour. FTIR spectroscopic technique was used to analyse the chemical changes in the wood through the correspondent reactions. Spectra indicated increasing intensity of the C@O and C-O stretching bands, and reduction in O-H stretching vibrations that re¯ects formation of less hygroscopic ester bonds with hydroxyl groups of cell wall polymers. Moisture adsorption isotherms show low equilibrium moisture content in esteri®ed wood at all relative humidity values as compared to a control. The adsorption data was analysed by applying Hailwood-Horrobin theory which separated the adsorbed water into hydrated water and dissolved water corresponding to mono-layer and multi-layer adsorption. Curve for M h and M s were similar in pattern for esteri®ed wood and control with different magnitude. Low M h and M s in esteri®ed wood indicate reduction in moisture adsorption sites. Inaccessible fraction of wood for water vapour was increased by 43%, 32% and 26% in acetic, maleic and phthalic anhydride treated wood, respectively, compared to the control. Acetic anhydride treatment was found most effective in reducing hygroscopicity of wood.

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- Building, Hevea brasiliensis, Maleic Anhydride, Relative Humidity

Endophytic fungi live inside plants as symbionts for at least one period of their life cycle. They play an important role in plant defence and could be promising sources of valuable natural bioactive products. The present study aimed to select endophytic fungi antagonistic to Microcyclus ulei, the agent of South American Leaf Blight (SALB) responsible for the weak development of rubber plantations in Latin America. Endophytic fungi were isolated from leaves of three cultivars (FX3864, CDC312, MDF180) of Hevea brasiliensis (the rubber tree) with distinct resistance levels to the attack by Microcyclus ulei. Leaf samples were collected from a 5,000 ha area of the Michelin plantations (Igrapiúna, Bahia, Brazil). A total of 435 colonies of endophytic fungi were isolated, purified, and preserved in sterilized distilled water. Lyophilized culture filtrates obtained from 88 fungal isolates, grown in liquid malt extract medium, were tested in vitro at concentrations of 50% and 12.5% for their inhibitory potential against the germination of M. ulei PMB26 conidia. Thirteen filtered cultures of endophytic fungi that presented inhibitory activity above 80% (at the concentration 12.5%) were characterized taxonomically by sequencing the ITS regions of rDNA, revealing the following taxa: Fusarium sp., Gibberella sp., Glomerella cingulata, Microsphaeropsis sp., Myrothecium sp., Pestalotiopsis sp. and Phomopsis sp. Three taxa were detected only in the resistant cultivars: Microsphaeropsis sp., and Pestalotiopsis sp. in MDF180, and Myrothecium sp. in CDC312. The present work constitutes the first study showing inhibitory activity of rubber tree endophytic fungi on Microcyclus ulei. These results provide an encouraging basis for the identification of new bioactive molecules for an effective control of South American leaf blight.

- by Ana Uetanabaro
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- Evolutionary Biology, Microbiology, Plant Biology, Latin America

Plant and bird diversity in the Indonesian jungle rubber agroforestry system was compared to that in primary forest and rubber plantations by integrating new and existing data from a lowland rain forest area in Sumatra. Jungle rubber gardens are low-input rubber (Hevea brasiliensis) agroforests that structurally resemble secondary forest and in which wild species are tolerated by the farmer. As primary forests have almost completely disappeared from the lowlands of the Sumatra peneplain, our aim was to assess the contribution of jungle rubber as a land use type to the conservation of plant and bird species, especially those that are associated with the forest interior of primary and old secondary forest. Speciesaccumulation curves were compiled for terrestrial and epiphytic pteridophytes, trees and birds, and for subsets of 'forest species' of terrestrial pteridophytes and birds. Comparing jungle rubber and primary forest, groups differed in relative species richness patterns. Species richness in jungle rubber was slightly higher (terrestrial pteridophytes), similar (birds) or lower (epiphytic pteridophytes, trees, vascular plants as a whole) than in primary forest. For subsets of 'forest species' of terrestrial pteridophytes and birds, species richness in jungle rubber was lower than in primary forest. For all groups, species richness in jungle rubber was generally higher than in rubber plantations. Although species conservation in jungle rubber is limited by management practices and by a slash-and-burn cycle for replanting of about 40 years, this forest-like land use does support species diversity in an impoverished landscape increasingly dominated by monoculture plantations.

- by Gregoire Vincent and +1
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- Agroforestry, Biodiversity Conservation, Land Use, Hevea brasiliensis

This study investigated certain aspects of physical and mechanical properties and resistance against biological deterioration of particleboard panels treated with extractives from different parts of Cerbera odollam trees. Particles of rubberwood (Hevea brasiliensis) treated with extracts of leaf, fruit, wood, bark, flower, and seed of Cerbera odollam were used to manufacture panels in laboratory conditions. Two types of adhesive, namely melamine urea formaldehyde and phenol resorcinol formaldehyde were used as binder for the panels. Treated panels had higher resistance against powder post beetle in laboratory as well as field exposures. Both thickness swelling and internal bond strength values of treated samples satisfied requirements for P4 Type particleboards stated in European Standards (EN 312). It appears that such extractives possess potential to enhance resistance of particleboard against insect damage in tropical countries.

This work reports a systematic comparative study of the technological properties of natural lattices and rubbers extracted from Hancornia speciosa Gomes and Hevea brasiliensis [(Willd. ex Adr. de Juss.) Muell.-Arg.] (clone RRIM 600) trees from 11 collections in Brazil throughout 2004. Natural rubber latex particle sizes and distributions were quite similar with an average diameter around 1 lm. Molecular weight, Wallace plasticity, and Mooney viscosity values were approximately the same for both rubbers. Fourier transform infrared spectroscopy peaks characteristic of natural rubber were observed for both Hancornia and Hevea. The measured differences in technological properties included lower values for Hancornia dry rubber content, % ash, % nitrogen, and plasticity retention index but higher value for acetone extract. Interestingly, nitrogen and protein content were much lower in Hancornia, suggesting that it may have important applications in nonallergic rubber uses. This represents the first report of lacticifer-produced low-protein natural rubber. V

- by Colleen McMahan and +1
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- Engineering, Comparative Study, Natural rubber, Applied

Disease surveys were conducted to appraise the incidence and severity of major leaf diseases of rubber in the non-traditional rubber growing areas of South India. Abnormal leaf fall (ALF) disease caused by Phytophthora sp., powdery mildew (PM) caused by Oidium heveae, colletotrichum leaf spot (CLS) caused by Colletotrichum spp and corynespora leaf fall (CLF) caused by Corynespora cassiicola were the disease included in the study. The study revealed that ALF, PM and CLS occured consistently in almost all the plantations surveyed, while CLF was not so wide spread in hilly areas. In Subramanya, Puttur, Belthangady, Kundapura and Sullia areas the incidences of both CLS and CLF occurred to aggravate the damage. Observations on incidence of diseases on different clones revealed that the clones, RRIM 600 and GT 1 suffered severely from ALF and PM diseases where as RRH 105 from CLF and CLS diseases.

- by Vinod K K
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- Hevea brasiliensis, Leaf diseases

Five rubber (Hevea brasiliensis) clones of the RRII 400 series derived from a cross involving RRII 105 and RRIC 100 along with
five other popular clones viz. PB 217, RRII 176, RRII 203, RRII 105 and RRIM 600, were evaluated in Jalpaiguri district of sub-
Himalayan West Bengal. Growth of clones in the immature and mature phases, rubber yield over seven years of tapping, biomass
and timber yield were recorded for assessing the suitability of clones to the region. Clones RRII 429, RRII 417 and RRII 203 were
superior in performance in the region compared to the recommended clone RRIM 600. Estimates of genetic parameters revealed
comparatively high heritability and scope for improvement of rubber yield by selection.

- by Shankar Meti and +1
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- Hevea brasiliensis

Differential scanning calorimetry (DSC) and a Rancimat method apparatus were applied to evaluate the oxidative stability of buriti pulp oil (Mauritia flexuosa Mart), rubber seed oil (Hevea brasiliensis), and passion fruit oil (Passiflora edulis). The Rancimat measurements taken for the oxidative induction times were performed under isothermal conditions at 100°C and in an air atmosphere. The DSC technique involved the oxidation of oil samples in an oxygen-flow DSC cell. The DSC cell temperature was set at five different isothermal temperatures: 100, 110, 120, 130 and 140°C. During the oxidation reaction, an increase in heat was observed as a sharp exothermic curve. The value T 0 represents the oxidative induction time, which is determined from the downward extrapolated DSC oxidative curve verses the time axis. These curves indicate a good correlation between the DSC T 0 and oxidative stability index (OSI) values. The DSC method is useful because it consumes less time and less sample.

Knowledge about the uses of rubber tree was known to the people of Arunachal Pradesh since many years before. They used to collect its latex at early age from naturally grown Rubber Tree (ficuselastica species is replaced by Heveabrasiliensis. was planted in 1980 for experimental purposes and it came to be used for commercial purposes since 1994. The study area is the main latex production area in the state. The study covered about the constraints for the rubber cultivation in the area. As per survey a report, people of the area is much interested to grow rubb but due to lots of constraints they could not reach at target. To achieve the objectives of the study, many tools have been used. For the reliability, information collected from sources and the field was analyzed by using MS word, MS excel and SPSS 18 p generating appropriate qualitative and quantitative result. The information has been gathered through field investigation and 500 household from rubber cultivators were taken as sample. It is also found that 2,500.00 hectares (approx) of land un plantation with 580 hectare under latex production.

- by kiryi potom
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- Geography, Climate Change, Climatology, Transformation

This study evaluated surface characteristics and overlaying properties of wood plastic composite (WPC) panels made from dry-blended rubber wood fiber-polypropylene (PP) powder formulations using a conventional flat-press process under laboratory conditions. Three levels of rubberwood fibers (Hevea brasiliensis), 40%, 50%, and 60%, based on the composition by weight, were mixed with the PP powder without and with 3% (based on weight) maleic anhydride grafted PP (MAPP) as a coupling agent. Contact angle measurements on the WPC samples were performed using a goniometer connected with a digital camera which collected one image per second. Roughness measurements, average roughness (R a ), mean peak-to-valley height (R z ), and maximum roughness (R y ), were taken from the sanded samples along and across the sandmarks using a fine stylus tracing technique. With increasing polymer content, surface roughness of the WPC panels improved while their wettability and adhesive bonding strength decreased. The formulations without MAPP were found to have higher surface roughness but they also had better wettability. Wettability and surface roughness of the WPC panels can provide good information on their ability to bond.

- by Nadir Ayrilmis
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- Surface Roughness, Building, Hevea brasiliensis, Contact angle

Corynespora leaf fall (CLF) disease caused by Corynespora cassiicola (Berk & Curt.) Wei. has emerged as major leaf disease of Hevea rubber infecting cultivated clones and causes economic losses. Sixty two cultivated Hevea clones were tested for CLF disease resistance under natural infection in the field and in the nursery. It was found that 10 clones in the main field and 4 clones in nursery showed no infection during initial screening, but subsequently they also showed differential reaction. Based on the average disease intensity across years, popular high yielding clone RRII 105 was found highly susceptible and commercially cultivated clones, RRIM 600 and GT l were classified under resistant group (PDI <5), while popular clones like RRII 208, PB 252, PB 5/51 and PB 213 were grouped as tolerant clones (PDI 5-l 0). Analyses of variance revealed significant variations among clones, year and clone x year's interaction components. Though average performance of clones vacillated across years, their susceptibility rankings remained relatively constant. Cluster analyses reveled natural grouping of five distinct clusters. The most susceptible clones, including RRII 105 remained very susceptible throughout the study period. None of the clones tested showed true genetic resistance bordering immunity. About 63% of clones in nursery and 68% in field tests were classed in the first cluster which showed some tolerance or lesser susceptibility to the disease (PDI 5-25). Clones in the remaining clusters were susceptible (PDI >25). As availability of suitable sources of resistance is a basic tool for the breeder, information generated is useful in successful resistance breeding programmes for CLF disease.

Rubber trees were introduced into the Malay Peninsula more than a century ago. The normal economical lifespan of a rubber tree is about 25 years, and, traditionally, rubberwood was used as fi rewood by the rural community. In recent decades, rubberwood has become an important timber for wood products, particularly in the furniture manufacturing sector, due to its attractive features, cream color, and good working properties. Sapstain, mold, and wooddecaying fungi are serious threats to rubberwood. Conventional chemical control has been a successful method of preventing staining fungal growth, but the effects of these chemicals are of concern because they create problems for the environment and public health. Thus, biological control has been recognized as an alternative approach to the problem. This article reviews the properties, potential utilization, and problems of protecting rubberwood against sapstain, mold, and wood-decaying fungi, and discusses the treatment methods available. Advances in biological control, particularly biofungicides, are emphasized as an alternative method for rubberwood treatment.

- by Yi Peng Teoh
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- Wood Science, Public Health, Biological Control, Case Study

Natural rubber latex (NRL), derived from the Hevea brasiliensis tree, is a material used to manufacture products in health care, including medical gloves. Proteins are a naturally occurring component of NRL. These proteins, which can be present on the surface of NRL gloves, have been related to hypersensitivity reactions in some humans who come into contact with them. These same proteins also help to maintain the latex colloidal stability during collection and transport prior to manufacture. Consequently, when measures are taken to remove or degrade these proteins, other problems can be introduced, such as destabilization of the latex and changes in its coagulation properties. Practical methods are available to reduce the extractable antigenic protein content of NRL products. We describe here methods of reducing proteins in commercial-grade NRL and finished products. NRL gloves manufactured with adequate leaching can produce products with lower levels of extractable antigenic proteins. Emphasis is given here to enzyme treatment of NRL, as this process is very effective in reducing antigenic proteins in NRL. While this technology adds marginally to the production cost of standard grades of NRL, it is still quite cost-effective when compared with postwashing NRL products or the use of synthetic latex. Moreover, enzyme-treated NRL maintains the excellent physical properties and performance of NRL. Ó

- by Anthony Gaspari
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- Health Care, Methods, Enzymes, LaTeX

The establishment of The Rubber Research of Malaysia (RRIM) in 1925 has started the research and development in various aspects related to rubber improvement in Malaysia. Many improvement programmes have been carried out to develop high yielding rubber clones and favourable characters such as low disease incident and wind resistance clones. For almost 90 years, RRIM has introduced the rubber planting recommendations to benefit rubber growers, plantations and smallholdings with the latest observations, evaluations and results obtained from the experimental trials. Rubber planting recommendations produced by RRIM has become the main reference for rubber growers over the years to gather the latest information of high yielding clones that available in Malaysia. There are continuously updated information related to rubber clones presented in the planting recommendations but prior to 1957 there are not much information disseminated through RRIM's internal reports and articles. Therefore, this review summarize the overview of RRIM rubber planting recommendations since 1925 and its impacts to the rubber growers in Malaysia.

- by Shamsul Bahri Abd Razak
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- Rubber breeding, Hevea breeding, Hevea brasiliensis

El artículo analiza la explotación de hevea brasiliensis en la región amazónica boliviana y la relación establecida entre dicha industria y la etnicidad regional. Dicha actividad puede rastrearse desde la mitad del siglo XIX en adelante, cuando se registran los primeros contactos entre el frente cauchero y los diferentes grupos étnicos que habitaban la zona. A través del análisis de diversas fuentes de misioneros, exploradores, políticos y de los mismos caucheros, el objetivo del trabajo es dar cuenta de las múltiples relaciones que los diferentes actores sociales trabaron en dichos encuentros desde el punto de vista de la larga duración. Se trata de cuestionar la visión tradicional sobre las sociedades indígenas y su presunta actitud pasiva frente al colonizador, contemplando en cambio un abanico de respuestas multiformes y situacionales que incluyó los tratos comerciales, los enfrentamientos armados, las relaciones amistosas e incluso de compadrazgo entre otras tantas opciones posibles.

- by Lorena Córdoba
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- Ethnohistory, Cultural Studies, Ethnic Studies, Latin American Studies

Vulnerability to water-stress-induced embolism of stems, petioles, and leaf midribs was evaluated for two rubber clones (RRIM600 and RRIT251). The xylem conduits were relatively vulnerable to cavitation with 50% of embolism measured for xylem pressures between -1 and -2 MPa. This feature can be related to the tropicalhumid origin of the species. A distinct basipetal gradient of vulnerability was found, leaf midribs being the least vulnerable. Substantial variation in vulnerability to cavitation was found between the two clones only at the petiole level. A correlation was found between the stomatal behavior and the development of cavitation. Stomata were nearly closed when the xylem pressure reached the point of xylem dysfunction. Stomata may thus contribute to controlling the risk of cavitation. However, for one clone a poor correlation was found between stomatal regulation and petiole vulnerability. This was consistent with a high degree of embolism measured in the petioles after a soil drought event. Therefore, xylem cavitation might represent a promising criterion to evaluate the performance of rubber clones under drought conditions.

- by Herve Cochard
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- Plant Biology, Water Stress, Hevea brasiliensis, Trees

Hevea brasiliensis is the major producer of natural rubber which is cis-l,4-polyisoprene. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) is involved in the biosynthesis of rubber and other plant products. We have used a hamster H M G R cDNA clone as a heterologous hybridization probe to isolate and characterize cDNA and genomic clones of H M G R from H. brasiliensis. Sequence analysis revealed that these clones fall into two different classes, HMGR1 and HMGR2. Comparison of the two classes shows 86 ~o nucleotide sequence homology and 95 ~o amino acid homology. The carboxy-termini of Hevea HMGRs are highly homologous to those of hamster, yeast and Arabidopsis HMGR. The amino-terminus ofHevea H M G R contains two potential membrane-spanning domains as in Arabidopsis H M G R while seven such domains are found in the HMGRs of other organisms. The apparent molecular mass of Hevea H M G R was estimated in western blot analysis to be 59 kDa. Northern blot analysis indicated that the H M G R 1 transcript of 2.4 kb is more highly-expressed in laticifer than in leaf. Genomic Southern analysis using 3'-end cDNA probes indicates the presence of at least two H M G R genes in Hevea.

- by Antoni Slabas
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- Genetics, RNA, Plant Biology, Plant Molecular Biology

Rubber leaf powder (an agricultural waste) was treated with potassium permanganate followed by sodium carbonate and its performance in the removal of Pb(II) ions from aqueous solution was evaluated. The interactions between Pb(II) ions and functional groups on the adsorbent surface were confirmed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDX). The effects of several important parameters which can affect adsorption capacity such as pH, adsorbent dosage, initial lead concentration and contact time were studied. The optimum pH range for lead adsorption was 4-5. Even at very low adsorbent dosage of 0.02 g, almost 100% of Pb(II) ions (23 mg/L) could be removed. The adsorption capacity was also dependent on lead concentration and contact time, and relatively a short period of time (60-90 min) was required to reach equilibrium. The equilibrium data were analyzed with Langmuir, Freundlich and Dubinin-Radushkevich isotherms. Based on Langmuir model, the maximum adsorption capacity of lead was 95.3 mg/g. Three kinetic models including pseudo first-order, pseudo second-order and Boyd were used to analyze the lead adsorption process, and the results showed that the pseudo second-order fitted well with correlation coefficients greater than 0.99.

- by Megat Hanafiah and +1
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- Earth Sciences, Kinetics, Water Purification, Scanning Electron Microscopy

Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry methods were established and utilized to examine the changes in protein expressions associated with post-germination of Hevea brasiliensis seed. No significant differences in the total number of proteins were observed but characteristic protein spots were present in both proteomes. The mature dry seed proteome contained clusters of proteins of about 36.5 and 23 kDa at pH 4-7 and a group of basic proteins at similar to pH 10. The presence of the 23 kDa proteins was markedly reduced in the post-germinated seed proteome. Approximately 60% of the proteins noted in the germinated seed proteome matched those of the mature dry seeds, with the remaining 40% protein spots as either unmatched or unique to the germinated seed proteome. Of the proteins detected, a putative beta-glucosidase, starch branching enzyme IIb and a MutT/nudix family of protein that were decreased in abundance in the germinated seed proteome and two proteins, acidic lectin and gibberellin 20-oxidase found unique to the mature dry seed proteome were identified by mass spectrometry. This report highlights the potential of using 2D-PAGE and mass spectrometry as means for identification of H. brasiliensis proteins and studying its seeds germination processes. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

- by Wong Pooi Fong
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- Plant Biology, Mass Spectrometry, Seed germination, Plant Science

The article discusses the construction of social representations on the Panoan indigenous peoples of Bolivian Amazonia during the rubber boom (late 19th Century and early 20th Century). It is argued that this imagery was neither homogenous nor stable, and that the Pacaguara, Chacobo and Caripuna were portrayed in multiple ways by their observers.

- by Lorena Córdoba
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- History, Cultural History, Ethnohistory, Cultural Studies

The adsorption of Cu(II) ions from aqueous solution by rubber (Hevea brasiliensis) leaf powder (RHBL) was studied in a batch adsorption system. Characteristics of RHBL such as pH of aqueous slurry, pH of zero point charge (pH ZPC ), surface area and pore diameter, Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS) were investigated. Factors influencing adsorption such as pH of the solution, adsorbent dosage, particle size, copper concentration and temperature have been studied. The adsorption process was relatively fast and equilibrium was achieved after about 60 min. Maximum adsorption of Cu(II) ions occurred at around pH 4-5. The kinetic data were analyzed using various kinetic models particularly pseudo-first-order, pseudo-second-order, Ritchie's-second-order and intraparticle diffusion. The pseudo-second-order kinetic model was found to agree well with the experimental data. Adsorption equilibrium data could also be described well by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. Based on the Langmuir isotherm, the monolayer adsorption capacity of Cu(II) ions was 8.92 mg g −1 . Thermodynamic parameters such as enthalpy change ( H • ), free energy change ( G • ) and entropy change ( S • ) were calculated and adsorption process was spontaneous and exothermic. Copper removal by RHBL involved different kinds of mechanisms such as ion-exchange, complexation and physisorption.

- by Megat Hanafiah
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- Chemical Engineering, Thermodynamics, Biochemical Engineering, Kinetics

Endophytic fungi isolates from foliage and sapwood of Hevea brasiliensis were studied to determine the total diversity of endophytes inhabiting leaves and sapwood, and differences between respective endophyte communities found in leaves... more

- by Romina Gazis
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- Conservation, Peru, Systematics, Biological Sciences

Hevea rubber clones are intensively cultivated in tropical regions of the world as main sources for Natural Rubber (NR) production which is one of the important raw materials for many industries. However, the heterozygous nature, long breeding time of trees and the prolonged period required for evaluation of mature traits are strong limitations for conventional breeding and selection methods. The development of methods for in vitro culture and genetic engineering has increased the possibility of producing rubber genotypes with improved latex yield, tolerance to tapping panel dryness (TPD) syndrome, growth rate and wood quality or reduction in undesirable traits. The combination of conventional breeding and molecular techniques will help to develop rubber trees with positive effects on the environment. However, the risks associated with the biotechnological applications should be carefully evaluated and field trials are to be performed with transgenic rubber tree. Genomic technologies were taken up by various research groups working on Hevea to identify new targets for breeding and/or complementary genetic transformation. In addition, molecular markers can provide simultaneous and sequential selection of agronomically important genes in Hevea breeding programs and effectively replace time consuming bioassays in early generation screens. With the advent of molecular techniques, several genes involved in rubber biosynthetic pathway have been characterized. Both HMGR and HMGS are essential enzymes involved in early steps of rubber biosynthesis. Among the genes identified, REF is a key rubber biosynthetic gene involved in polymerization of isoprene chain. However, further research is needed to use these identified genes for genetic manipulation of rubber tree. Most recently, a set of genes associated with TPD has been identified by SSH analysis. This review provides a comprehensive picture on rubber biotechnological research achievements in the last two decades.

- by rekha karumamkandathil and +1
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- Genetics, Plant Science, Genetic Engineering, Tissue culture

A field study was carried out to understand the dynamic nature of two major leaf diseases, Corynespora leaf fall (CLF) and Colletotrichum leaf spot (CLS) of rubber plants (Hevea brasiliensis). These diseases appeared regularly in the rubber plantations and caused more damages to younger leaves. Fresh infection of CLF disease was observed in the plantation from the second fortnight of January during the period of refoliation and the disease intensity was maximum from the second fortnight of March to the first fortnight of April. The disease decreased considerably after the onset of rains and remained mild until the next reflushing season. The disease intensity was limited to refoliation period after the annual wintering and warm humid periods only. The CLS disease was present throughout the year in the plantation at all the stages of leaves. However, the disease intensity was mainly confined to younger plantations. The disease was found to establish with the refoliation and became more severe during the rainy season and warm humid months. Unlike CLF, this disease did not cause considerable economic damage to mature rubber, but it is a serious problems in nurseries and for very young rubber plants in the main field.

- by Vinod K K and +1
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- Mycology and Plant pathology, Hevea breeding, Hevea brasiliensis

El artículo describe la continuidad paradójica entre la actitud crítica de los misioneros católicos respecto del tratamiento de la mano de obra indígena durante el llamado boom cauchero en la Amazonía boliviana, a fines del siglo XIX y comienzos del XX, y la posterior relación de mayor complejidad que establecieron los misioneros protestantes del Instituto Lingüístico de Verano con los chacobos (flia. ling. pano) desde la década de 1950 hasta su salida de Bolivia en la década de 1980. Estos últimos no sólo incentivaron activamente a los indígenas a trabajar la industria cauchera e integrarse a la economía regional, sino que además iniciaron políticas explícitas e implícitas para intervenir en la sociabilidad indígena: conformación de estructuras centralizadas de liderazgo político, relaciones de compadrazgo, implementación de la patronimización, promoción de la familia nuclear en detrimento de la familia extensa, prohibición del matrimonio bilateral de primos cruzados, la alianza serial, sororal, poligínica, etc. Asimismo, se describen las prácticas y estrategias indígenas para absorber selectivamente dicha agenda, viabilizar la convivencia e incorporarse exitosamente a la sociedad nacional.

- by Lorena Córdoba
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- Religion, History, Ethnohistory, Cultural Studies

Rubber industry has increased the requirements for quality and uniformity of natural rubber produced in Brazil. Technological properties of latex and natural rubber of clones GT 1, PB 235, IAN 873 and RRIM 600 [Hevea brasiliensis (Willd.... more

- by Mariselma Ferreira
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- Natural rubber, Hevea brasiliensis, Nitrogen, Environmental Conditions

The best-yielding, best vigour and most stable Hevea clones are identified by growing clones in different environments. However, research on the stability in Hevea brasiliensis (Willd. Adr. ex Juss.) Muell.-Arg. is scarce. The objectives of this work were to assess genotype-environment interaction and determine stable genotypes. Stability analysis were performed on results for girth growth and rubber yield of seven clones from five comparative trials conducted over 10 years (girth growth) and four years (rubber yield) in São Paulo State, Brazil. Stability was estimated using the Eberhart and Russell (1966) method. Year by location and location variability were the dominant sources of interactions. The stability analysis identified GT 1 and IAN 873 as the most stable clones for girth growth and rubber yield respectively since their regression coefficients were almost the unity (β = 1) and they had one of the lowest deviations from regressions (S di 2 ). Their coefficient of determination (R 2 ) was as high as 89.5% and 89.8%

Activated carbon was prepared from rubberwood (Hevea brasiliensis) sawdust by steam and chemical treatments. Steam activation was carried out in high temperature fluidized bed reactor (FBR) using steam as quenching medium. Chemical activation was carried out by using phosphoric acid. The adsorption capacity was determined by using iodine number and methylene blue number and surface area by ethylene glycol mono ethyl ether (EGME) method. Further the adsorption studies were carried out using malachite green dye. Langmuir, Freundlich and Temkin adsorption isotherms were analyzed and Langmuir isotherm shows satisfactory fit to experimental data. The adsorption capacity was found to decrease in the order; steam activated carbon > acid + steam activated carbon > commercial activated carbon > acid activated carbon. Temperature effects on adsorption were carried out and it was found that the adsorption reaction was endothermic. Thermodynamic analysis of the process confirms its endothermicity. The adsorption kinetics was found to follow pseudo-second-order kinetic model.

- by lima miranda
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- Chemical Engineering, Mass Transfer, Kinetics, Activated Carbon

A laboratory scale study was conducted to assess the suitability of rubber leaf litters as vermiculture substrates for Perionyx excavatus, Eudrilus eugeniae and Eisenia fetida. Earthworm mortality, their rate of body weight increase and reproduction were measured during the investigation. In E. eugeniae, E. fetida and P. excavatus, the rate of increase of body weight was 28.8, 6.2 and 5.04 mg worm -1 day -1 , respectively, in rubber leaf litter. Mortality of the adults was very high (50 %) in P. excavatus when compared with that (17 %) of both Eisenia and Eudrilus. Rate of reproduction in rubber leaf litter diet for both E. eugeniae (1.4 young worm -1 week -1 ) and E. fetida (1.3 young worm -1 week -1 ) was significantly higher (P < 0.05) than that in P. excavatus (0.2 young worm -1 week -1 ) over a period of 62 days. From our present investigation, it appeared that the suitability of rubber leaf litters as a vermiculture substrate for the species studied was in the descending order: E. eugeniae > E. fetida > P. excavatus.

- by Gautam Bhattacharjee
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- Plant Biology, Hevea brasiliensis, Soil sciences, Leaf Litter

Pengadaan dan penanganan bibit klonal tanaman karet di Balai Penelitian Sungei Putih ialah bibit klonal stadia stum okulasi mata tidur dan bibit polybag. Kegiatan dalam penanganan stum okulasi mata tidur meliputi: pencabutan stum, seleksi stum, dan penanganan stum sebelum di salurkan. Pengadaan dan penangan bibit polybag, kegiatannya meliputi: pengisian tanah kedalam polybag, penyusunan polybag, penanaman, pemeliharaan bibit polybag, dan seleksi bibit polybag.
Presentase stum okulasi mata tidur yang lulus dapat ditingkatkan dengan melakukan pengendalian serangan penyakit jamur akar putih serta kemahiran tenaga kerja dalam melakukan pencabutan dan seleksi. Penggunaan serbuk gergaji lembab dapat menjaga stum dari benturan dan menjaga kesegaran bibit hingga siap tanam di lapangan. Media tanah pada penanaman stum dalam polybag harus padat dan arah tunas okulasi harus menghadap Utara-Selatan, agar memperoleh bibit polybag yang bermutu baik. Layu Fusarium adalah penyakit paling berbahaya pada pembibitan polybag, maka perlu dilakukan pengendalian dengan penyemprotan fungisida berbahan aktif Tridimefon dengan kosentrasi 0.5%, rotasi dilakukan setiap satu minggu sekali

- by Ade Siagian
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- Hevea brasiliensis

This research reports results from preliminary data collection for carbon sequestration estimation of rubber plantations. The objective of this study is to determine the stomatal conductance, chlorophyll content, diameter and height at different growth stages of rubber tree saplings. Stomatal conductance, chlorophyll content, diameter and height were measured on the rubber tree (Hevea brasiliensis) saplings. The measurements were done in two weeks period on twenty saplings for each of two growth stages, i.e, 45, and 90 days respectively, and seventeenth saplings for growth stage of 135 days. Electronic devices were used to measure stomatal conductance, chlorophyll content and stem diameter, while measurement tape was used to measure the height of the samples to avoid destructive samplings. Results showed that stomatal conductance decreased with increased growth stages of rubber tree saplings. Chlorophyll content was highest at a growth stage of 90 days, followed by 45 days and 135 days. However, for diameter and height, results indicated the increase in both variables with increase growth stages of saplings. ANOVA of stomatal conductance, chlorophyll content, diameter and height within the growth stages of rubber trees saplings were analysed. From the analysis, the means of stomatal conductance, chlorophyll content, diameter and height were found to be significantly different within the growth stages of rubber tree saplings (P≤0.05). Since rubber plantation is one of the major plantations in Malaysia, the findings from this study may be useful as baseline information on the physiology of rubber trees.

- by Mohd Nazip
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- Statistical Analysis, Agriculture, Carbon Sequestration, Hevea brasiliensis

The present study evaluates the impact of different stimulation frequencies of Ethephon in downward tapping on the production potential of trees in upward tapping of the clone PB 260 of Hevea brasiliensis. Six parameters are measured: production per tree, tapping panel dryness percentage and four latex biochemical parameters which were dry rubber content, inorganic phosphorus, sugar and thiols. The results show that in downward tapping, generally, the biochemical parameters level is inversely proportional to the stimulation frequency during years 9 and 10. Regarding the production, beyond four stimulations per year, it is inversely proportional to the stimulation frequency. When the trees are tapped upward with a four stimulation uniform per year, the production continues to be low according to the preceding frequency stimulation in downward tapping beyond four stimulations per year. However, the factors which caused this decrease don't seem to be the same in the first and the second years of upward tapping. In the first year of upward tapping, according to the evolution of the biochemical parameters, the decrease in production is linked to physiological tiredness due to the stimulation in downward tapping. On the other hand, in the second year, it is a phenomenon of familiarization to Ethephon which could explain the decrease in production on treatments which received more than four stimulations per year in downward tapping. In second year of upward tapping, the trees need more than four times per year Ethephon stimulations to reach their production potential. Get the full articles at: http://www.innspub.net/ijaar/assessment-of-the-efficiency-of-essential-oils-of-ocimum-gratissimum-l-lamiaceae-and-hyptis-suaveolens-l-poit-lamiaceae-in-the-biological-control-against-sclerotinia-of-abelmoschus-esculentus/

- by INNSPUB Journals
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- Agronomy, Research Methodology, Open Access Publishing, Educational Research

La presente investigación se realizó en la región hulera del Papaloapan, Estado de Oaxaca, México. El objetivo fue obtener ecuaciones para estimar la biomasa total aérea del clon IAN-710 de Hevea brasiliensis Müll. Arg., con base en el diámetro normal (DN). Se utilizó una muestra de 28 árboles de esta especie con DN 10 a 40 cm. El peso seco de los árboles varió de 89.74 kg a 807.06 kg. El peso seco del follaje representó 5.4% del peso seco total en árboles pequeños (DN 10 cm), pero sólo 1.7% en árboles de mayor tamaño (DN 40 cm). La proporción de biomasa contenida en el tallo se correlacionó positivamente con el tamaño del árbol y, por tanto, se incrementó en los árboles grandes. Los valores oscilaron de 87.3% en árboles de 10 cm DN a 88.9% en árboles de 40 cm. La ecuación logarítmica (log P = β β β β β 0 + β β β β β 1 log d) tuvo un mejor ajuste (R 2 =0.98)y una dispersión normal de los residuales. Con la biomasa estimada se podrá calcular el carbono acumulado en los árboles en cada uno de sus componentes a diferentes edades.

- by J. Jesús Vargas Hernández
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- Hevea brasiliensis, Dry Weight

Peranan hevein dalam lateks pohon karet telah mendorong penelitian-penelitian tentang keberadaan enzim proteolitik yang memiliki peranan dalam pembentukan hevein. Tujuan dari penelitian yang dilakukan adalah untuk mengisolasi dan menentukan karakter protease yang berasal dari BSL lateks karet klon PR-255 dan WR-101. Penelitian dimulai dengan mengambil lateks segar dan sentrifugasi untuk memperoleh tiga fraksi utama. Fraksi bawah yang mengandung partikel lutoid dikumpulkan dan dilakukan proses beku-cair untuk memecah membrane lutoid, larutannya kemudian disentrifugasi dan supernatant dikeringkan dengan menggunakan alat freeze dryer. Pemurnian protease dari BSL dilakukan dengan tahap-tahap pengendapan dengan kejenuhan 0-100% garam ammonium sulfat, kromatografi filtrasi gel dengan Sephadex G25, kromatografi penukar kation CMC CM32 dan kromatografi penukar anion DEAE DE 32. Kedua protease yang berhasil diisolasi memiliki aktivitas optimum pada pH 7,5 dan waktu inkunasi selama 30 menit. Sedangkan suhu optimum pada 55°C untuk klon PR-255 dan 50°C untuk WR-101. Protease tersebut memiliki berat molekul sebesar 67 kDa. Penentuan jenis protease dengan menggunakan inhibitor spesifik menunjukkan bahwa kedua protease tersebut tergolong protease sistein.

- by Safri Ishmayana
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- Protease, Hevea brasiliensis, Hevein

Cassiicolin is a host-selective toxin (HST) produced by the fungus Corynespora cassiicola (strain CCP). It is responsible for the Corynespora leaf fall (CLF) disease, which is among the main pathologies affecting rubber tree (Hevea brasiliensis). Working on purified cassiicolin and using electron microscopy, we have demonstrated that this 27-residue O-glycosylated protein is able to induce cellular damages identical to those induced by the fungus on rubber tree leaves and displays the same host selectivity. The solution structure and disulfide pairing of cassiicolin have been determined using NMR spectroscopy and simulated annealing calculations. Cassiicolin appears to have an original structure with a prolate ellipsoid shape. It adopts an over-all fold consisting of three strands arranged in a righthanded twisted, antiparallel β-sheet knitted by three disulfide bonds. Its conformation resembles that found in small trypsine-like inhibitors isolated from the brain, the fat body and the hemolymph of locust grasshoppers. But cassiicolin has no sequence homology with these protease inhibitors, and lacks their characteristic substrate-binding loop. Probably, this motif represents one of the few highly stabilized "minimal" scaffolds, with a high sequence permissiveness, that nature has selected to evolve over different phyla and to support different functions. The knowledge of the 3D structure opens the way to the delineation of the mechanism of action of the toxin using site-directed mutagenesis.

- by Robert Thai and +1
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- Electron Microscopy, Molecular Biology, Simulated Annealing, NMR Spectroscopy

Tapping panel dryness (TPD) condition affects the production of latex in Heveu brasiliensis plantations. Latex production is severely decreased in diseased plants and can be completely shut down in the ultimate stage of the phenomenon. In search of the molecular basis of the disease, we have analysed the changes in latex protein pattern during the development of this condition, Five proteins specific to the cytosolic compartment of latex were found to be related to the disease. Major changes consisted of a dramatic increase of a 26-kDa and a 145kDa protein in diseased plants and minor changes affected a SkDa, a 34kDa and a 21-kDa protein. The 26-kDa protein was found to be linked to the coagulation process. Its accumulation is specifically correlated to the disease development and is inhibited by ethylene. The 14.5kDa protein accumulates preferentially in the severe stages of the condition. A disfunctioning of the coagulation process is proposed to be the major cause of the syndrome.

- by ABDOURAHAMANE SANGARE
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- Plant Biology, Plant Science, Hevea brasiliensis

The effects of planting density on growth and development of rubber (Hevea brasiliensis Muell. Arg., clone RRIC 100) and banana (Musa spp. cv. Kolikuttu) were examined to determine the optimum planting density of banana when grown in combination with rubber. The experiment comprised five treatments, sole crop rubber (R), sole crop banana (B) and three intercropping treatments consisting of an additive series of one (BR), two (BBR) and three (BBBR) rows of banana to one row of rubber. Planting density of banana was 500, 1000, 1500 and 1700 plants ha-1 in the BR, BBR, BBBR and B treatments and 500 plant ha-1 for rubber in all treatments. Growth analysis commenced at 8 months after planting (MAP) and at the onset of the experiment, rubber plants were four months old. Density had significant effects on both leaf area index (LAD and total dry matter (TDM) of the stand, with the highest values in the most dense BBBR treatment. TDM, leaf area and dry matter partitioning to above-ground components of banana were significantly greater in the BBR and BBBR treatments than in the BR crop. Dry matter productivity and the crop performance ratio (CPR) of rubber also increased with planting density. Plant weight of rubber showed similar relations with both stem girth and height measurements, with improved performance in the intercrop relative to sole crop treatments. Treatments had little affect on bunch yield per banana plant, harvested percentage and CPR, with mean values of 6.2 kg, 65.3% and 0.95, respectively. Since yield per plant was similar across treatments, yield per hectare increased significantly with increasing banana density. Amongst intercrops, the highest density BBBR treatment always performed best in terms of both stand parameters and performance of individual component crops. It was concluded that increasing the density of banana, from a single to three rows, increased biomass productivity per unit area, with no adverse effect on the growth and yield of either component rubber or banana crops.

- by V.H.L.Rodrigo Rodrigo
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- Field Crops, Growth and development, Growth Analysis, Hevea brasiliensis

The extent of carbon (C) sequestration in soils under agroforestry systems in relation to soil types (fraction sizes) and vegetation structure remains largely unexplored. This study examined soil C storage, an indicator of C sequestration potential, in homegardens (HGs), natural forest, and single-species stands of coconut (Cocos nucifera), rice (Oryza sativa)-paddy, and rubber (Hevea brasiliensis), in Thrissur district, Kerala, India. Soil samples collected from four depth zones up to 1 m were fractionated to three size classes (250 -2000 µm, 53 -250 µm, <53 µm) and their total C content determined. Total C stock (Mg ha −1 ) was highest in forests (176.6), followed by managed treebased systems, and lowest in rice-paddy field (55.6). The results show storage of higher amounts of C in the <53 µm fraction, the most stable form of C in soil, up to one-meter depth, in land-use systems with high stand density of trees such as forests and small-sized HG. Although the results do not allow comparison of changes in soil C stock in different land-use systems, they show higher C storage in soils under tree-based land-use systems compared with the treeless (ricepaddy) system, especially in lower soil depths, suggesting the higher soil C sequestration potential of tree-based systems, and thereby their role in reducing atmospheric concentration of carbon dioxide.

- by Vimala Nair
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- Climate Change, Carbon Dioxide, Carbon, Agroforestry
- by M Hanafiah
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- Earth Sciences, Water, Kinetics, Adsorption

Cultivation of rubber trees on non-forested land could act as a carbon sink by sequestering carbon in biomass and indirectly in soils. International political and economical interests, following the Kyoto Protocol, require estimates of... more

This study investigated land-use and landcover change in three hamlets and two state rubber farms in the Nan-e watershed of the Xishuangbanna prefecture of Yunnan province in Southwestern China. The overall objective of the study was to understand how state policies affected land use and land cover and how changes in these variables affected farmer vulnerability to economic, social, and political events. Emphasis was placed on the cultivation of rubber (Hevea brasiliensis), promoted in southern Yunnan province since the 1950s as a means to meet the demands of rapid economic development. The study combined remote sensing analysis with secondary data and in-field interviews in order to understand the coupling between landuse and land-cover change and farmer vulnerability in light of the geographic, historical, and sociopolitical situation.

- by X. Jianchu
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- Geography, Environmental Management, Agriculture, Economic Development

Current ex situ collections of the wild rubber tree Hevea brasiliensis were gathered more than 25 years ago mainly from populations in Southwest Amazonia. Information regarding the structure of genetic diversity among these populations is fragmented and needs refinement. Having analyzed polymorphisms at 15 microsatellites loci throughout the Hevea genome, we report on the genetic diversity of 307 clonally propagated individuals from 19 different collection points. All analyzed loci were highly polymorphic, averaging 21.7 alleles per locus, and displayed heterozygote deficiency. Differentiation among populations was analyzed on a subsample of 220 individuals from 14 populations. The overall F ST is 0.12; although low, this value is significant and suggests moderate differentiation. Mato Grosso (Brazil) populations were genetically more distant from all other populations. A highly significant correlation between genetic and geographical distances over the whole area under study was shown by the Mantel test. The Bayesian algorithm used by STRUCTURE software allowed for the identification of three population clusters that match the boundaries of hydrographical basins of the main Amazon River tributaries. Differentiation among populations could therefore be jointly explained by both geographical location within the hydrographical Amazon network and by isolation by distance among populations belonging to distinct catchments. It is likely that some of these populations no longer exist due to severe deforestation. We provide suggestions to improve genetic resource management and sampling strategy in natural populations of H. brasiliensis.

- by Fabien Doare
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- Genetics, Polymorphism, Agricultural Biotechnology, Genetic Diversity

Research and development in the field of biodiesel showed that fatty acid methyl esters synthesized from agriculture or animal oils and fats, which exhibit qualifying properties, can replace diesel fuel used in internal combustion engine. However, the industry had some downfall recently with the fluctuating prices of edible oils and increasing demand for nutritional needs. Crude rubber seed oil (CRSO) and crude palm oil (CPO) were used in this study since both can be extracted and produced locally in Malaysia from their abundant plantations. The benefits of introducing such blend are that CRSO is considered a nonedible feedstock with no major industrial utilizations that has the potential to reduce the usage of CPO in biodiesel industry and was found to enhance the cold flow characteristics when blended with CPO by reducing the saturated fatty acids in the feedstock. The oils and blends were characterized for density, kinematic viscosity, heating value, acid value, free fatty acid content, refractive index, mono-, di-and triglycerides and sulphur content. Fatty acids composition and iodine value were established for an equivolume blend of the oils.

- by Murni Ahmad
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- Engineering, Technology, Internal Combustion Engine, Research and Development

Perennial tree crops are often grown in complex multistrata systems that incorporate natural vegetation. These systems contribute simultaneously to sustaining rural livelihoods and to the conservation of biodiversity, but their productivity is usually low. Introduction of high yielding germplasm, usually selected in monocultural plantations, is a potential way to increase productivity, but a critical requirement is that such plants can be established in a competitive multispecies environment. The establishment of clonal planting stock in the jungle rubber agroforests of Indonesia was explored through participatory on-farm research. The trial involved four farmers who grew clonal rubber trees in a total of 20 plots, constituting five replicate experimental blocks spread across four farms. Unexpectedly, vertebrate pest damage by monkeys (Presbytis melalophos nobilis) and wild pigs (Sus scrofa) was the most important influence on establishment, explaining almost 70% of the variation in rubber tree growth. The amount of labour invested in weeding was also positively correlated with rubber tree growth. Farmers generally decided to completely cut back vegetation between rows of rubber trees, including potentially valuable trees, rather than weeding within the rows and selectively pruning trees in the inter-row. Farmers thought that the inter-row vegetation would harbour vertebrate pests and compete with the clonal rubber, and they had access to fruits, firewood and other non-timber forest products from other land. Thus, contrary to expectations, when offered clonal germplasm, farmers opted to use plantation monoculture methods to protect what they considered a valuable asset, rather than maintain the traditional multispecies strategy they use with local germplasm.

- by gede sandi
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- Agroforestry, Indonesia, Hevea brasiliensis, Rubber

Wood-substituted composites from matrices based on ternary mixtures of benzoxazine, epoxy, and phenolic novolac resins (BEP resins) using woodflour (Hevea brasiliensis) as filler are developed. The results reveal that the addition of epoxy resin into benzoxazine resin can lower the liquefying temperature of the ternary systems whereas rheological characterization of the gel points indicates an evident delay of the vitrification time as epoxy content increased. The gelation of the ternary mixtures shows an Arrhenius-typed behavior and the gel time can be well predicted by an Arrhenius equation with activation energy of 35-40 kJ/mol. For wood-substituted composites from highly filled BEP alloys i.e. at 70% by weight of woodflour, the reinforcing effect of the woodflour shows a substantial enhancement in the composite stiffness i.e. 8.3 GPa of the filled BEP811 vs 5.9 GPa of the unfilled BEP811. The relatively high flexural strength of the BEP wood composites up to 70 MPa can also be obtained. The outstanding compatibility between the woodflour and the ternary matrices attributed to the modulus and thermal stability enhancement of the wood composites particularly with an increase of the polybenzoxazine fraction in the BEP alloys.

- by Chanchira Jubsilp
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- Rheology, Multidisciplinary, Wood, Viscosity

BACKGROUND: This research describes the adsorption of copper ions from aqueous solutions following the modification of rubber (Hevea brasiliensis) leaves with formaldehyde solution. The main objectives of this research were to identify the binding mechanisms of copper ions on the chemically modified rubber leaves by spectroscopic techniques and to investigate the effects of several important physicochemical parameters such as pH, copper concentration, contact time, adsorbent dose and temperature on copper removal.

- by Megat Hanafiah
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- Thermodynamics, Kinetics, Chemical, Multidisciplinary

- by Luiz H C Mattoso
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- Natural rubber, Hevea brasiliensis, Nitrogen, Environmental Conditions

- by Suryo Hardiwinoto
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- Agroforestry, Biodiversity Conservation, Land Use, Hevea brasiliensis

Natural rubber (NR) from the Hevea brasiliensis tree is the main commercial feedstock for rubber and latex dipping industries. NR latex particles in a matured commercial latex concentrate are stabilized by charged groups derived from proteins, long-chain fatty acid soaps and polypeptides adsorbed on the particle surface. The colloidal stability of the latex is extremely sensitive to pH as well

- by Kanjanee Nawamawat
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- Engineering, Atomic Force Microscopy, Natural rubber, Physical sciences