The rubber tree, Hevea brasiliensis, is cultivated in many humid tropical countries for the latex it produces, from which is extracted natural rubber mainly used by the tyre industry. Asia alone provides almost 95 % of the world production, where the first producer is Thailand whose rubber industry earns a regular income for 10 % of the population. However, a disease is attacking rubber trees that causes irreversible drying-up of latex flow, and can affect up to 30% of trees in African, Asian and American plantations, causing marked falls in production and substantial economic losses. Termed “rubber tree bark necrosis syndrome” (RTBN), it was diagnosed in 1983 (4) in an industrial-scale plantation estate (Michelin company, Ivory Coast) by IRD researchers. The first investigations, conducted at the request of the plantation company, could not establish a link between RTBN and any pathogenic agent (fungus, virus, bacterium or mycoplasm).
Further research projects were launched at the end of 1999 by the IRD team and its partners (2) at the request of the rubber production sector and with its support (1). This complex syndrome was then tackled using a multidisciplinary approach (involving plant pathology, agricultural soil science, cell and molecular physiology, virology, and so on) and focusing on several different localities (3), which provided conditions for identifying its origin and activating mechanism.
Since the 1970s, the predominant basis of rubber cultivation has been propagation by grafting on tree stock. In 90% of cases, RTBN attacks the tree vascular tissues, starting right at the grafting point situated in the transition zone between the trunk and the roots, the collar. The first stage of the disease is not detectable because the first cells to undergo necrosis are located in internal tissues of the bark. The necrosis, however, extends steadily to the whole base of the trunk before travelling upwards, up to the tapping notch. At this stage, the notch no longer produces latex and the affected trees are then noticeable. When the outer bark becomes diseased, cracks begin to appear starting from it and then dead parts flake off.
Marie Guillaume | alfa
Light green plants save nitrogen without sacrificing photosynthetic efficiency
21.11.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign
Filling intercropping info gap
16.11.2017 | American Society of Agronomy
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences