Injured, diseased plants can make a chemical phone call to their roots to seek help in recovering. Although this amazing self-healing process can save a plant from numerous illnesses, there are many injuries – including damage to them by humans and some animals – that are outside its bailiwick.
Plant Intelligence
Plants are smarter than most people realize. They don’t just live in their dirt environment as passive entities who are dependent upon the vagaries of temperature and light when it comes to producing beautiful flowers or nourishing vegetables.
When attacked by destructive fungi and bacteria, plants know how to reach for help. Parasitic plants can even get help from a host plant’s communication system.
Diseased Plants Cry for Help
If attacked by a pathogen, such as disease-causing bacteria, a plant’s leaf can signal its roots for help. The roots then manufacture an acid that brings beneficial bacteria to the rescue.
University of Delaware Professor Harsh Bais and his colleagues conducted one of the first studies of how diseased plants communicate their needs and achieve self-healing. They detected transmission of a “call for help” from the leaves to the roots in plants that had Bacillus in the soil. The roots responded by secreting malic acid, a carbon-rich chemical that can be biosynthesized by all plants. In their study the malic acid was secreted to attract beneficial microorganisms. Magnified images of plant leaves and roots revealed the accelerated defense response provided.
More about Self-healing Plants
Dr. Bais’ specialty relates to the mechanisms and regulatory processes controlling root secretion. He says root-root, root-microbe, and root-nematode communications are continuous occurrences in the rhizosphere, but due to the underground nature of roots, these intriguing interactions have largely been overlooked.
In this instance researchers know where the message is transmitted from and where it is received. Great discoveries are full of baby steps that define paths for future research. In this case, the next step is to discover what the message itself is.
National Science Foundation Funds Plant Research
Much of the research cited above was funded by the National Science Foundation and the University of Delaware. The study was described in an article “Root-Secreted Malic Acid Recruits Beneficial Soil Bacteria,” Rudrappa, Czymmek, Paré and Bais, in the journal Plant Physiology (148:1547-1556, 2008).
Ongoing research providing new information about myriad plant functions is necessary for maximizing and protecting the nature of a human-accessible, nutrition-based food supply in a future world full of changing conditions that we can only begin to imagine.
Rosemary E. Bachelor - Rosemary Bachelor, a prize-winning journalist, has had a career as an editor, feature writer, magazine publisher and author. Her latest ...
