March 30, 2009
Aspirin for Potatoes?
In the 1930s, scientists came across a phenomenon in plants that they called systemic acquired resistance (SAR, not SARS). The plants made salycylic acid in response to the presence of pathogens. Sometimes the plants did not respond quickly enough so experiments are being done to see if spraying the plants with salycylic acid can stimulate potatoes to defend themselves. They fight off the infection rather than kill the pathogen. Read more about this in the library or at http://www.ars.usda.gov/is/AR/archive /dec03/plant1203.htm .
Plants of the Colosseum
Five plant surveys, dating from 1643 to 2001, taken at Rome's Colosseum allow scientists to study the plant life at one site over an unusually long period of time. Although the current list of 242 names is down from the 420 high of 1855, an amazing 200 were seen in all of the surveys. Changes in the lists indicate a trend to a warmer, drier climate. Part of that trend is caused by the fact that the Colosseum, once on the outskirts of the city, is now encircled by it.
Recent studies show that people were growing squash in what is now southwestern Ecuador as long as 10,000-9,000 years ago, about the same time that people were domesticating squash in the highlands of southern Mexico. The evidence came from carbon dating of microscopic crystals from squash rinds found at two prehistoric sites in Ecuador.
Plants Also Have Clocks
Plants have a 24-hour biological clock that they use to protect themselves from the sun. A series of chemical changes leads to the production of flavonoids which act as a “sunscreen” to protect the plant from the afternoon sun.