Garden flowers have a sense of smell? I don't think so. The vegetables growing in my backyard have an aversion to being touched? Surely not. Trees remember the weather? Now you are kidding. Daniel Chamovitz, the director of the Manna Centre for Plant Biosciences at Tel Aviv University, is kidding no one. He aims to shock: "Think about this: plants see you," reads the opening line of "What a Plant Knows."

Mr. Chamovitz believes that we pay too little attention to the "immediately sophisticated sensory machinery in the flowers and trees." To make amends he has foraged through the latest plant-science research in pursuit of the premise that plants do indeed possess senses.

He devotes a chapter to each—sight, smell, touch, hearing, an awareness of place and the sense of memory (memory, as Mr. Chamovitz reminds us, depends on sensory inputs)—and compares the human experience with that of plants. He is willing to admit that plants do not have the ability to hear: Seeds that germinated faster when exposed to music turned out to be taking advantage of the heat generated by the speakers. But otherwise, Mr. Chamovitz concludes: "On a broad level we share biology not only with chimps and dogs but also with begonias and sequoias."

So does the cherry tree "know" when to flower? Or is it programmed by evolution to switch on flowers in spring? After all, as the author concedes, plants lack either a central nervous system or a coordinating brain. Mr. Chamovitz, however, urges us not to underestimate plants. On a genetic level plants are more complex than many of the animals that share our planet. They have the ability to sense what is going on in the outside world and to share that information among flower, stem, leaf and root. Look at the head of the sunflower that turns to face the sun. The flower may sense the sun's direction, but it is the stem that must twist in response.

The author presents plenty of data to suggest that plants are sensitive. The burr cucumber (Sicyos angulatus) can detect and respond to a weight of 0.009 ounces (0.25 grams). If humans, who can barely detect 0.07 ounces (two grams), possessed the same level of sensitivity, a lover's kiss would resemble a slap in the face.

A hard avocado placed in a brown paper bag with a ripe banana will ripen because the avocado "senses" the ripe fruit's chemicals. The rapacious behavior of the parasitic dodder (Cuscuta pentagona) uses smell to hunt down its prey. You don't need a nose in order to smell, argues Mr. Chamovitz, who suggests the definition: "to perceive odor or scent through stimuli."

He illustrates a plant's sense of touch with the Venus flytrap: one touch and snap! Charles Darwin described the flytrap—which not only photosynthesizes for a living but moonlights as a carnivore—as "one of the most wonderful plants in the world." Today we can measure the speed of the flytrap's bite (one 10th of a second) and identify its cause—a chemical reaction that is triggered when two hairs on the inside surface are touched. As Darwin noted, the "filaments" or hairs can differentiate between the touch of a raindrop and that of an edible fly.

There is also the Mimosa pudica, whose frondy leaves momentarily wilt when touched. The case of the drooping Mimosa is due to a group of cells, the pulvinus, that act like mini mechanical pumps forcing water down out of the cells in the leaf. Mr. Chamovitz does not look at the reason for this behavior (is the plant playing dead to avoid being browsed by some predator?), but he does reveal the mechanics. The critical signal, touch, affects high concentrations of potassium inside the pulvinus cells. Touch causes potassium channels to open and potassium (and water) to flow out. The cells become flaccid, and the leaf wilts. But what regulates the opening of these potassium channels is calcium, "the same ion," the author notes, "critical for neural communication in humans."

Our sharing a chemical function with plants calls to my mind James Lovelock's Gaia hypothesis, arguing that our planet is one big living organism. But be mindful, warns Mr. Chamovitz. We have been here before in the unsubstantiated territory of Peter Tompkins and Christopher Bird's "The Secret Life of Plants." Published in the spiritually questing 1970s, it made what plant physiologist Arthur Galston described as "bizarre claims presented without adequate supporting evidence." Then there was Dorothy Retallack, who in the early 1970s set out to prove that plants could hear. Desperate to confirm that loud rock music aurally damaged young people, she purported to show how plants, exposed to healthy doses of Bach and Schoenberg, thrived while those closeted with Hendrix and Zeppelin grew wan and etiolated. Case proved? Not at all. Her experiments didn't meet even minimal scientific standards

Journalists often blur crucial distinctions in such matters. Scientists have shown, for instance, that young trees can detect not only insect damage to their neighbors but even the presence of torn leaves. They respond by releasing self-protective chemicals to make their own leaves less palatable. One newspaper, inaccurately, referred to "talking trees whose bark is worse than their blight."

"What a Plant Knows" comes with a cautionary note from the author: "If you're looking for an argument that plants are just like us, you won't find it here." The reader will, however, find enough absorbing science to concede that plants continue to inspire and amaze us. It's time, as Joni Mitchell sang at Woodstock, "to get ourselves back to the garden" and take a closer look at plants.