While attending the annual conference of the Indiana Native Plant and Wildflower Society (INPAWS) last fall I purchased a copy of a book entitled What a Plant Knows: A Field Guide to the Senses written by Daniel Chamovitz, Director of the Manna Center for Plant Biosciences at Tel Aviv University.
Being skeptical of the book’s title, I was happy to read a note on the jacket cover penned by Stephen D. Hopper, Director of London’s Royal Botanical Garden, which said the book was “ . . . lively, eloquent, scientifically accurate, and easy to read.”
In its reasonably short six chapters, the book discusses what a plant sees, smells, feels, hears, how a plant knows where it is, and how a plant remembers. Writing in Chapter One, “What a Plant Sees,” Chamovitz pens “. . . plants see the same ultraviolet light we see and can tell when it is very bright or dull, if it’s coming from the left or right, and how long the light has been on.”
He records the fact that, about the time of WWII, scientists learned that the time when a plant flowers can be manipulated by short and long periods of light. For instance, a poinsettia plant will bloom in time for Christmas when the light is reduced to only 9 hours.
In the Chapter Two, “What a Plant Smells,” he writes “Of course, plants don’t have noses but they release a bouquet of odors into the air around them” and goes on to say, “Indeed, they have an olfactory sense and can differentiate between smells.”
The smell of a ripe banana placed into a bag with a hard avocado will cause it to ripen and the odor of cut up figs will trigger an entire bunch to ripen. Why? Both contain a small amount of a molecule called ethylene (a universal plant hormone) which ages both fruits.
He also reports the fact that when a leaf is attacked by an insect or bacteria, it releases odors that warn its brother leaves to protect themselves from attack.
All of us have been witness to the proof that plants feel. This is apparent when we’ve touched leaves of the Mimosa Tree (Albiza julibrissin) which then droop only to reopen, or watched an insect land on the leaf blades of a Venus Flytrap (Dionaea muscipula).
Chamovitz writes in Chapter Three, “What a Plant Feels,” that “plants can differentiate between hot and cold and know when their branches sway in the wind.”
Can a plant hear? In spite of a number of scientific experiments in the past 40 years, the author writes, “until it is proven otherwise, it looks as if all evidence tells us that plants (can’t hear) and are indeed ‘deaf’.” Chamovitz addressed the question of how a plant knows where it is in Chapter Five when he writes “all of us know that the main signal is sunlight. Turn a plant upside down and it will reorient itself upwards in a slow-motion manner.” Further, he says that plants are constantly aware of where their branches are and if they are growing perpendicular to the ground or at an angle off to one side.
The last chapter of the work, “What a Plant Remembers,” informs the reader that plants have the ability to store and recall biological information — although remedial — such as they do remember when to bloom and the effect of periods of cold on their seeds.
Is the book an interesting read? YES. Does one have to be a botanist to understand it? NO. All in all, it is a fascinating look at what a plant’s life is all about and well worth the time.
Ed Myers, (EMyers3670@aol.com), is an Advanced Master Gardener and is a past president of both Garfield Park Master Gardener Association and the Irvington Garden Club. He is the club’s steward of Irvington’s Benton House Historic and Kile Oak Habitat Gardens.