A photo from open sources
Alexander Ponomarenko from Grenoble University (France) claims that trees in high drought stress levels make sounds that can register and use as signs of a plant hazard water shortage. Droughts like the 2010 Russian or American 2012, spawn in healthy looking trees cavitation processes that can be detected directly. /National Geographic Droughts similar to the Russian 2010 or American 2012, spawn in healthy looking trees cavitation processes that can be detected directly. Why it happens? In a tree trunk, water and a number of substances rise up networks of xylem vessels from the roots to the tops. Because the trees high, then, for the water delivery to work, the pressure in the vessels can many times superior to atmospheric. But, as in the tube for cocktails when the water in the vessel ends and is already missing to fill the entire container, bubble formation may begin. IN as a result, with moisture deficiency in xylem, cavitation starts processes that the tree is almost unable to withstand. And if their the scale is too large, the plant will be injured or even will die like a person in case of gas embolism when the bubbles air in the circulatory system cause serious damage to blood vessels. To identify cavitation in the tissues of a tree, scientists under the guidance of Mr. Ponomarenko used a piece of pine trunk placed in gel that was designed to simulate the environment inside living plants. Then water was gradually removed from the gel, simulating conditions drought. At the same time, the sample was taken with a high-speed camera and recorded sounds coming from him on a microphone. And here is what succeeded find out: the occurrence of bubbles recorded by the camera, and sounds cavitational nature coincide in time, and the latter are responsible for 50% of sounds in the ultrasonic range from the plant. The rest half was due to extraneous processes such as hitting air bubbles into cells adjacent to xylem vessels. Scientists believe that microphones tuned to similar sounds quite able to help detect drought symptoms in another healthy-looking tree, including in biocenoses, where such plants are on the verge of extinction due to frequent recent decades of global droughts warming.