Professor Rainer Hedrich, scientist and biophysicist at Julius-Maximilians-Universität (JMU) in Würzburg in Bavaria, Germany has been studying plants for over 35 years.
In particular, Hedrich studies how plants regulate their water balance: and now he may have made one of the most surprising discoveries of his life: plants seem to “remember” days of drought.
The memory of the drought
Plants have a whole new and unexpected way to save water. Hedrich's group discovered this new anti-drought strategy together with researchers at the University of Adelaide in Australia.
The results were published in the journal Nature Communications.
A key factor called GABA
From the paper I read that plants use the signaling molecule GABA (gamma-aminobutyric acid) to remember the days of drought. The drier the climate, the more GABA accumulates in plant tissue during the day. And the next morning, the amount of GABA determines how widely the plant opens the pores of the leaves, to save more or less water.
It is as if the plants were adjusting their behavior of the day based on the drought of the day before.
What is GABA?
As mentioned, GABA is a signaling molecule which in humans and animals is a messenger substance in the nervous system. Plants have no nerve cells and no brain: yet GABA is also found in them, and in connection with processes similar to memory!
Rainer Hedrich names another connection. It seems that "short-term memory", which the carnivorous Venus flytrap plant (a plant very popular in plant experiments) uses to count the number of times its prey touches it, depends on the level of calcium in the cell. The same calcium level that regulates the enzymatic biosynthesis of GABA in plants.
Low water requirement, high drought tolerance
The GABA effect has been demonstrated in various crops, as the professor explains Matthew Gilliham from the University of Adelaide: “Under the influence of GABA, barley, broad beans and soya, for example, close the pores of their leaves.” Even laboratory plants “mutated” to produce more GABA react in this way. In experiments, they need less water and survive drought longer.
There are other signaling substances in plants that cause leaf pores to close, but GABA relies on a completely different mechanism of action
Bo Xu, first author of the study – Australian Research Council Center of Excellence in Plant Energy Biology.
In the future? Drought resistant plants
In times of climate change, the water saving mechanism and drought tolerance of plants are increasingly important issues.
