The sneezing droplets are important carriers of diseases such as flu in the population. American researchers have found that some plant leaves also fly tiny droplets of water, spreading pathogens to nearby plants, just like sneezing.
Researchers at Virginia Tech have observed this phenomenon in wheat infected with fungal infection with leaf rust. The tiny water droplets carrying the spores of the fungus fly automatically from the blade, up to 5 mm, enough to get rid of the binding of the air layer on the surface of the blade and fly to other plants under the influence of the breeze.
The researchers said that this phenomenon is caused by fluid mechanics. When two water droplets fuse, the surface tension decreases, and part of the surface energy is converted into kinetic energy, which “bounces” the water droplets out. This phenomenon only occurs on very hydrophobic surfaces, as is the case with wheat leaves. If the leaves are infected, the pathogen may adhere to the water droplets and spread.
It has been known before that this type of “ejection” occurs on other types of hydrophobic surfaces. The new study is the first time it has been found to be a route of plant disease transmission. On the surface of wheat leaves where leaf rust occurs, fungal spores are easily attached to water droplets and about 10 spores per hour per square centimeter.
Researchers say that if the mechanism plays an important role in the spread of plant diseases such as leaf rust, anti-control schemes can be developed for its characteristics, such as spraying specific substances to form coatings on the leaves, reducing surface hydrophobicity.