Hevea brasiliensis

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 <i>Phytophthora</i> 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.

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.

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.

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.

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.

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.

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

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/

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.

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