About a year ago, a group of researchers discovered Palmer is resistant to the herbicide class known as PPO-inhibitors, due to a mutation -- known as the glycine 210 deletion -- on the PPX2 gene. "We were using a quick test that we originally developed for waterhemp to determine PPO-resistance based on that mutation.Tranel and his colleagues decided to sequence the PPX2 gene in plants from Tennessee and Arkansas to see if they could find additional mutations. Sure enough, they found not one, but two, located on the R98 region of the gene. "Almost all of the PPO-resistant plants we tested had either the glycine 210 deletion or one of the two new R98 mutations. None of the mutations were found in the sensitive plants we tested," Tranel says. Furthermore, some of the resistant plants had both the glycine 210 deletion and one of the new R98 mutations. Tranel says it is too early to say what that could mean for those plants. In fact, there is a lot left to learn about this resistance mechanism. Tranel hopes they will be able to determine how common the three mutations are in any given population. "That way," he says, "when a farmer sends us a resistant plant and it doesn't come back with the glycine 210 deletion, we will be able to tell him how likely it is that he's dealing with another one of these mutations." In the meantime, other research groups or plant testing facilities could use the new genetic assay to detect the mutations in Palmer samples. Tranel hopes they will. "The more labs testing for this, the more we learn about how widespread the mutation is," he says.
Palmer amaranth is a nightmare of a weed, causing yield losses up to 80 percent in severely infested soybean fields. It scoffs at farmers’ attempts at control, having evolved resistance to six classes of herbicides since its discovery in the United States 100 years ago. And now, scientists have discovered it has two new tricks up its sleeve. If this weed continues to resit the herbicides, then we can not control the growth nor the spread of it. https://www.sciencedaily.com/releases/2017/04/170404124409.htm
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The team around the former GFZ PhD student of the GFZ section Climate Dynamics and Landscape Evolution, Gordon Schlolaut (now Japan Agency for Marine-Earth Science and Technology), investigated sediments from Lake Suigetsu in Japan, to reconstruct East Asian climate change during the Younger Dryas. Achim Brauer, Head of the GFZ section Climate Dynamics and Landscape Evolution and Director of the Department Geoarchives says: "Little by little we come to understand the interplay between regional climate changes at the end of the last glacial phase. The scientists assume that this warming was related to changes in atmospheric pressure that pushed cold polar air masses and with them the westerlies that are determinant for the European climate further north, which before, during the glacial phase, reached down to Southern Europe. The algae of the investigated lake, and the spores and pollen from plants that were surrounding the lake, that were deposited throughout the centuries of the cold period, as well as changes in the chemical composition of the sediments, provide the scientists with important information on regional changes in temperature and rainfall. Like parts of a puzzle, these different regional archives provide an overall picture of the climatic changes during that time and show how regional climate changes were influencing each other.
The climate of the Earth follows a complex interplay of cause-and-effect chains. A change in precipitation at one location may be caused by changes on the other side of the planet. A better understanding of these "teleconnections" -- the linkages between remote places -- may help to better understand local impacts of future climate change. A look into the climate of the past helps to investigate the teleconnections. https://www.sciencedaily.com/releases/2017/03/170331120340.htm "We've determined that most of the gas ever present in the Mars atmosphere has been lost to space," said Bruce Jakosky, principal investigator for MAVEN and a professor at the Laboratory for Atmospheric and Space Physics (LASP). MAVEN team members had previously announced measurements showing that atmospheric gas was being lost to space and that described the processes by which atmosphere was being stripped away. Young stars have far more intense ultraviolet radiation and winds, so atmospheric loss by these processes was likely much greater early in Mars' history, and these processes may have been the dominant ones controlling the planet's climate and habitability, according to the team. The team used this enrichment together with how it varied with altitude in the atmosphere to estimate what fraction of the atmospheric gas has been lost to space. In sputtering, ions picked up by the solar wind impact Mars at high speeds and physically knock atmospheric gas into space. The team made its estimate using data on the Martian upper atmosphere from MAVEN's Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument supported by measurements from the Martian surface made by NASA's Sample Analysis at Mars (SAM) instrument on board the Curiosity rover.
Solar wind and radiation are responsible for stripping the Martian atmosphere, transforming Mars from a planet that could have supported life billions of years ago into a frigid desert world, according to new results from NASA's MAVEN (Mars Atmosphere and Volatile Evolution Mission) spacecraft led by the University of Colorado Boulder. This is important to know because this could be the same fate for Earth. We should look into ways to prevent this potential issue. https://www.sciencedaily.com/releases/2017/03/170330142211.htm |
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May 2017
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