In 1956, the Würzburg botanist Otto Ludwig Lange observed an unusual phenomenon in the Mauritanian desert in West Africa: he found plants whose leaves could heat up to 56 degrees Celsius.
In 1956, the Würzburg botanist Otto Ludwig Lange observed an unusual phenomenon in the Mauritanian desert in West Africa: he found plants whose leaves could heat up to 56 degrees Celsius. It is astonishing that leaves can withstand such heat. At the time, the professor was unable to say which mechanisms were responsible for preventing the leaves from drying out at these temperatures. More than 50 years later, the botanists Markus Riederer and Amauri Bueno from Julius-Maximilians-Universität Würzburg (JMU) in Bavaria, Germany, succeeded in revealing the secret.
To understand what the two scientists discovered, one must know more about the somewhat complicated structure of a plant leaf. Plant leaves, for example, have a skin that is usually invisible to the human eye. "You can see the skin in the tomato," explains Professor Riederer, head of the JMU Chair of Botany II. Bioscientists speak of the "cuticle". It can be imagined as a very thin plastic foil. Without this foil, the leaf of the plant would dry out within a short time: “the water permeability of a cuticle is even lower than that of a plastic foil.”
Constant trade-off: Open or close pores?
The plant skin is not a continuous layer that would extend over the whole leaf. It contains numerous pores, called stomata, which can open and close. The plant “feeds” through these stomata. Riederer: "it thereby uptakes the carbon dioxide the plant needs for photosynthesis.”
Read more at University of Würzburg
Image: The Wuerzburg biologists Markus Riederer (left) and Amauri Bueno found out why the leaves of the date palm do not dry out even at temperatures above 50 degrees Celsius. (Credit: JMU Wuerzburg)