Plants can tell the difference between their enemies and family members, thanks to chemical signals. They don’t need to see or hear to do this.
Canadian researchers in 2007 found a plant that recognized as its siblings plants grown from the same seeds of a common maternal plant. Since then, other researchers have verified this phenomena and learned even more about how plants recognize each other and what they do about it.
How Plants Treat Their Enemies
Plants get aggressive with plants that they decide don’t share the same mother plant with them. Their reaction to an encounter with a stranger most commonly is to vigorously compete for soil nutrients and moisture. They quickly send out more roots to get a bigger share of the available water and minerals in the soil.
This competitive behavior was studied by Prof. Harsh Bais and doctoral student Meredith Biedrzycki at the University of Delaware. Their study used wild populations of a small flowering plant. Young seedlings were exposed to root secretions from family members, from strangers, or even their own root secretions.
Plant Rivalry
The study measured the length of the longest lateral root extending to the sides of the downward growing primary root. Also measured was the hypocotyls, first leaf-like structure formed by the plant.
The result? Plants exposed to chemical signals from strangers had larger lateral root formation. That’s not all. When plants grown from seeds of the same plant grow next to each other, they don’t mind having their leaves touch each other and often will intertwine. Stranger plants who are neighbors are literally uptight. They grow upright and avoid touching each other. It should be noted that similar studies have had differing results.
How Plants Treat Family Members
Plants given chemical signals from their seed mates didn’t aggressively branch out with lateral roots to capture a greater portion of the food supply. They didn’t appear to mind sharing nutrients and water in the ground, nor light from overhead.
Studies are also being conducted on whether or not plants recognize themselves. The common feature of self/non-self recognition found in multiple studies is that roots must be physiologically attached to be recognized as self. The genetically identical roots of detached clones are recognized as non-self.
Plant Behavior Research Continues
Professor Blais wants to learn more about how the sibling plants survive so well without competing. For him, there’s always a new question around the bend. Meanwhile, he has a special message for home gardeners. If you’ve got plants that are not doing well, don’t blame the garden center where they were purchased, or assume they have a disease. They may just not like their neighbors.
To further explore this topic, readers can access online an article co-authored by Canadian bio9llogist Susan A. Dudley and Gujillermo P. Murphy titled “Kin Recognition: Competition and Cooperation in Impatiens (Balsaminaceae), which appeared in the American Journal of Botany, Vol. 96, Issue 11 (November, 2009)
Source: This study, funded in part by the National Science Foundation, appears in Vol. 3, No. 1 (January-February, 2010) of the journal Communicative & Integrative Biology, which is accessible online, as: Meredith L Biedrzycki, Tafari A Jilany, Susan A Dudley, and Harsh P. Bais, “Root Exudates Mediate Kin Recognition in Plants.”
KEYWORDS: plants, plant behavior,plant rivalry,plant sibling recognition,plants know relatives,aggressive plant behavior,welcoming plant behavior,how plants recognize self,harsh bais,susan Dudley,Meredith Biedrzycki
Rosemary E. Bachelor - Rosemary Bachelor, a prize-winning journalist, has had a career as an editor, feature writer, magazine publisher and author. Her latest ...
