No love for the lady ginkgos

Washington DC Department of Urban Forestry nips stinky seeds in the bud By Liza Lester, ESA communications officer. A male Gingko biloba in Lafayette Park, flanking the White House. Credit, Liza Lester April, 2012. As an urban arboreal companion, the ginkgo has much to recommend it. Its tall branches bring welcome summer shade, the fans of its leaves turn a lovely gold in the fall, it copes well with city pollution, lives for thousands of years, and isn’t prone to disease or insect infestation. But it has a serious drawback. In the fall, mature female ginkos produce fleshy seeds (not a “fruit” in the parlance of botany, as the ginkgo is not an angiosperm, or flowering plant), and unlike cherry season, the height of ginko reproduction is not a time of celebration. The seeds drop all over city streets, smelling “like dirty socks and vomit.” Some city dwellers hate the trees so much that they are willing to cut them down rather that endure the annual mess. Rather than massacre female ginkgo trees all over the city, this week DC’s Urban Forestry Administration will spray the trees with “Shield EC” aka “Sprout Nip” aka “chlorpropham,” an herbicide that interferes with the division of plant cells during growth. Agricultural distributors typically use chlorpropham to discourage potatoes from sprouting after harvest. Buds and shoots  – anywhere the plant is actively growing – are hotspots of cell division, and the incipient ginko seed buds fall off before they can grow stinky. At least, that’s the idea. Not all customers are satisfied. Since only female trees are a problem, it would make sense to plant only male trees. But male and female trees look identical when their reproductive parts aren’t hanging out. It can be a good two decades before a tree matures and begins to produce either pollen cones or seeds. Botanist CL Lee’s argument for an X/Y sex determination scheme (like the human mechanism), pointing to a subtle chromosomal difference between the sexes, has not been confirmed in the fifty years since he proposed it. Genetics has not provided an easy solution. Although Chinese scientists have been looking for molecular signatures that would allow botanists to sex young saplings, there is no easy test as of yet. Instead, nurseries now take cuttings of mature male trees to create “clones” of the male tree, either inducing root growth, or grafting the cutting to the roots of a young tree (sometimes this backfires when the graft fails and the root stock turns out to be female, hence reports of male trees turning female). But in the meantime there are robust, mature female trees...

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Persevering pikas, herbicide inhalation in farm states and prehistoric pathogens

Southern Rockies picas unaffected by climate change: A new study from the University of Colorado at Boulder has found that American pikas, despite being temperature-sensitive animals, have not been adversely impacted by climate change. The researchers who conducted the study assessed 69 historical sites known to host pikas within the southern Rockies ranging from southern Wyoming through Colorado and into northern New Mexico. The results showed that 65 of the 69 sites have retained their pika populations. The study was funded primarily by the National Geographic Society. The new study stands in contrast to a study from another research group earlier this year in Nevada’s Great Basin that showed a nearly five-fold increase in local extinction rates of pika populations in the past decade. The different results may be because the more recent study area of the southern Rocky Mountains offers habitats in higher elevations that are also more contiguous than are habitats in Nevada’s Great Basin, according to the study’s researchers. The American pika, which shares its mammal family order with rabbits and hares (lagomorpha), lives in mountainous regions including British Columbia, Washington, Oregon, Idaho, Montana, Utah, Wyoming, Colorado, Nevada, California and New Mexico. In 2010, the U.S. federal government denied an endangered species listing for the American pika partially because there were insufficient data on its distribution and abundance across western North America. Federal scientists find herbicide in air, water samples: U.S. Geological Survey (USGS) scientists report that air and water samples taken from the states of Mississippi and Iowa show that there are considerable levels of a harmful herbicide in the air and water within the states. The federal agency scientists reported that there were significant levels of the chemical glyphosate (used in “Roundup” herbicide) found in every stream sample examined in Mississippi in a two-year period as well as in the majority of air samples. This means people have been inhaling the herbicide, though no known detrimental effects have been yet documented. According to USGS, it is difficult and costly to test for the presence of glyphosate, which is why there has been so little research on its impacts on air and water to date. The herbicide is the most-used worldwide where it is applied to  residential yards, golf courses and farm fields.  Scientific studies have revealed that its wide use has led to glyphosate-resistant ‘super weeds.” USGS scientists affirm that more research is necessary to document effects on soil organisms, plants, animals and people. The USGS data has been submitted to the Environmental Protection Agency for further review. Read more at “U.S. researchers find roundup chemical in water, air” Prehistoric pathogens: DNA contained in recently acquired...

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