How plants survive 'salt' pain
Plants are using a "calcium wave" to survive in the increasingly salty or saline soils that have become a problem the world over, research suggests.
Increasing salinity in soil poses a significant problem as salt is toxic to plants.
Recent research by Won-Gyu Choi and his colleagues at University of Wisconsin-Madison has found that calcium plays a key element in plants' initial response to salt.
When plants sense salt they respond by creating a "calcium wave", an elevated concentration of calcium ions that passes in a ripple from the point of salt perception, throughout the plant.
The wave is created by the release of calcium that the plants store within their cells.
During the study, the authors exposed plant roots to various stimuli, including cold, touch, or stress, the plants generally responded with elevated calcium concentrations at the point of application.
When roots sensed salt, calcium rose at the point of contact, followed by neighbouring cells in a continuous wave travelling at two cells per second throughout the plant.
The calcium wave travelled from the roots all the way to the tips of the shoots and leaves above ground within two minutes.
When the plants' shoots received the signal, they altered what they were doing.
In fact, they mounted a defence response of sorts.
The calcium wave that plants create in their roots to inform the rest of the plant that salty times are ahead has striking similarities to our nervous system.
In humans, calcium is also used to signal from one neuron to another when we experience stress, such as pain, the researchers said.
(Posted on 11-05-2014)