Bad News For Vegans - Plants Can Sense Touch, Smell, and Even Hear Themselves Being Eaten
Vegans base their entire dietary patterns around abstaining from the use and consumption of animal products usually revolving around a philosophy (and opinion) that they are rejecting the commodity status of sentient beings. Unfortunately, the foundation of veganism is based on, at the very least, erroneous conclusions. Many vegans refuse to accept the fact that plants are also sentient beings and science has now shown that the kingdom Plantae have many of the same senses as animals. They are conscious organisms which can touch, smell, taste and even hear themselves being eaten. According to many vegans, that's acceptable because they have to eat something, however plant scientists are throwing their entire philosophy into a whirlwind as studies show that when it comes to senses, plants are really no different than even humans.
Future enlightened consumers of foods will not necessarily fall into any specific category whether vegetarian, fishetarian, vegan, raw or any other known pattern. They will simply be interested in eating clean, fresh, unadulterated foods that agree with both their palate and physiology.
In all my discussions with some fairly educated and well-informed vegans, three things are always quite clear: 1) many base their dietary practices on morals and opinions rather than science; 2) many flat out refuse to acknowledge that carnivorous diets have benefited and continue to benefit specific populations due to ancestral dietary patterns; and 3) they don't like to think about plants as sentient beings that can sense as humans and animals do.
Plants have scientifically been show to draw alternative sources of energy from other plants. Plants influence each other in many ways and they communicate through "nanomechanical oscillations" vibrations on the tiniest atomic or molecular scale or as close as you can get to telepathic communication. However, their sense and communication are measureable in very much the ways as are humans.
Plants are able to sense and optimally respond to so many environmental variables--light, water, gravity, temperature, soil structure, nutrients, toxins, microbes, herbivores, chemical signals from other plants--that there may exist some brainlike information-processing system to integrate the data and coordinate a plant’s behavioral response.
Electrical and chemical signaling systems have been identified in plants which are homologous to those found in the nervous systems of animals. Neurotransmitters such as serotonin, dopamine, and glutamate have all been found in plants.
According to many plant scientists plants perceive their circumstances and respond to environmental input in an integrated fashion. They have an intrinsic ability to process information from both abiotic and biotic stimuli that allows optimal decisions about future activities in a given environment.
In so many ways, we must stop regarding plants as passive objects--the mute, immobile furniture of our world--and begin to treat them as protagonists in their own dramas, highly skilled in the ways of contending in nature. It is only human arrogance, and the fact that the lives of plants unfold in what amounts to a much slower dimension of time, that keep us from appreciating their intelligence and consequent success. Plants dominate every terrestrial environment, composing ninety-nine per cent of the biomass on earth. By comparison, humans and all the other animals are, in the words of one plant neurobiologist, "just traces."
Plants Can Hear Themselves Being Eaten
Researchers at the University of Missouri (MU) found that plants can identify sounds nearby, such as the sound of eating, and then react to the threats in their environment.
'Previous research has investigated how plants respond to acoustic energy, including music,' said Heidi Appel, senior research scientist in the Division of Plant Sciences in the College of Agriculture, Food and Natural Resources and the Bond Life Sciences Center at MU.
'We found that "feeding vibrations" signal changes in the plant cells' metabolism, creating more defensive chemicals that can repel attacks from caterpillars.'
When caterpillars later fed on both sets of plants, the researchers found that the plants previously exposed to feeding vibrations produced more mustard oils, a chemical that is unappealing to many caterpillars.
'What is remarkable is that the plants exposed to different vibrations, including those made by a gentle wind or different insect sounds that share some acoustic features with caterpillar feeding vibrations did not increase their chemical defenses,' Cocroft said.
'This indicates that the plants are able to distinguish feeding vibrations from other common sources of environmental vibration.'
Plants can hear the vibrations produced by insects, such as a bee's buzz or an aphid's wing beat, and minuscule sounds that might be created by even smaller organisms. Plants even benefit from the ability to detect certain sounds produced by other plants. For example, researchers at the Institute of Plant Sciences in Bern, Switzerland, recently recorded ultrasonic vibrations emanating from pine and oak trees during a drought, perhaps signalling to other trees to prepare for dry conditions.
Stefano Mancuso from the International Laboratory of Plant Neurobiology at the University of Florence, Italy, and his colleagues are starting to apply rigorous standards to study plant hearing Their preliminary results indicate that corn roots grow towards specific frequencies of vibrations. What is even more surprising is their finding that roots themselves may also be emitting sound waves.
Plants Can Touch
Plants live in a very tactile world. Branches sway in the wind, insects crawl across leaves, and vines search out supports to hang on to. Plants are even sensitive to hot and cold, allowing them to respond to the weather by doing things like changing their growth rates and modulating their use of water. Simply touching or shaking a plant is often enough to reduce its growth, which is why vegetation in windswept locations tends to be stunted.
All plants can sense mechanical forces to some degree, but tactile sensitivity is most obvious in the carnivorous Venus flytrap. When a fly, beetle or even a small frog crawls across its specially adapted leaves, these spring together with surprising force, sandwiching the unsuspecting prey and blocking its escape. The Venus flytrap (pictured) knows when to shut because it feels its prey touching large hairs on the two lobes of the trap. But it won't just snap shut with any stimulation - at least two hair touches must occur within about 20 seconds of each other. This helps to ensure that the prey is the ideal size and will not be able to wiggle out of the trap once it closes.
The mechanism by which the Venus flytrap feels its prey is uncannily similar to the way you feel a fly crawling on your arm. Touch receptors in your skin sense the insect and activate an electrical current that passes along nerves until it reaches your brain, which registers the fly's presence and instigates a response. Likewise, when a fly rubs up against the Venus flytrap's hairs, it induces a current that radiates throughout the leaves. This activates ion channels in the cell membrane and the trap springs shut, all in less than one-tenth of a second.
Although most plants do not react this fast, they feel a mechanical stimulus in the same way. What's really fascinating is that even at the level of individual cells, plants and animals use similar proteins to feel things. These mechanoreceptors are embedded in the cell membranes and, when stimulated by mechanical pressure or distortion, they allow charged ions to cross the membrane. This creates a difference in electrical charge between the inside and the outside of the cell, which generates a current. Unlike us, plants lack a brain to translate these signals into sensations with emotional connotations. Nevertheless, their sensitivity to touch allows them to respond to their changing environments in specific and appropriate ways.
"They have analagous structures," Michael Pollan explains. "They have ways of taking all the sensory data they gather in their everyday lives ... integrate it and then behave in an appropriate way in response. And they do this without brains, which, in a way, is what's incredible about it, because we automatically assume you need a brain to process information."
Pollan says plants have all the same senses as humans, and then some. In addition to hearing, taste, for example, they can sense gravity, the presence of water, or even feel that an obstruction is in the way of its roots, before coming into contact with it. Plant roots will shift direction, he says, to avoid obstacles.
So what about pain? Do plants feel? Pollan says they do respond to anesthetics. "You can put a plant out with a human anesthetic. And not only that, plants produce their own compounds that are anesthetic to us."
Researchers in Bonn, Germany, found plants give off a gas when under 'attack'. Super-sensitive microphones picked up a 'bubbling' sound from a healthy plant. But this rose to a piercing screech when it was under threat. 'The more a plant is subjected to stress, the louder the signal,' said Dr Frank K,hnemann. Plants do not actually scream in pain. But different sounds are heard when the gas they emit, ethylene, is bombarded with lasers.
Plants Can Smell
The parasitic vine called dodder is the sniffer dog of the vegetable world. It contains almost no chlorophyll - the pigment that most plants use to make food - so to eat it must suck the sugary sap from other plants. Dodder uses olfaction to hunt down its quarry. It can distinguish potential victims from their smell, homing in on its favourites and also using scents emitted by unhealthy specimens to avoid them.
Dodder is exceptionally sensitive to odours, but all plants have a sense of smell. In animals, sensors in the nose recognise and bind with molecules in the air. Plants also have receptors that respond to volatile chemicals. What do they smell?
Back in the 1920s, researchers with the US Department of Agriculture demonstrated that treating unripe fruit with ethylene gas would induce it to ripen. Since then, it has become apparent that all ripening fruits emit ethylene in copious amounts, can smell it, and respond by ripening. This ensures not only that a fruit ripens uniformly but also that neighbouring ones ripen together, producing more ethylene and leading to a ripening cascade. Coordinated ripening is important because it attracts animals to eat the fruit and disperse the seeds. Ethylene is a plant hormone that regulates many processes, so being able to smell it has other advantages too, such as in the coordination of leaf-colour changes in the autumn.
Above all, however, smell allows plants to communicate. Research in the 1980s showed that healthy trees in the vicinity of caterpillar-infested ones were resistant to the pests because their leaves contained chemicals that made them unpalatable. Other trees isolated from the infestation did not produce these chemicals, so it seemed that the attacked trees had sent an airborne pheromonal message that primed healthy trees to prepare for imminent attack. We now know that many volatile chemicals are involved.
More scientists are indeed questioning whether plants are behaving more like animals than previously ignored. In 2005 researchers founded the Society for Plant Neurobiology to advance in this debate. A founder of the organization, the Italian scientist Stefano Mancuso, argues that we should stop assuming that a brain is needed for intelligence. Even without neurons and a brain, plants can acquire, process, and integrate information to shape their behavior in a way that could be called intelligent.
Psychologists and philosophers will likely debate the precise definition of intelligence until the end of time. It may in truth blend into the whole continuum of biological capacities--faculties of various kinds, particularly sensation and memory, that seem to exist throughout the animal world. But as we realize that plants have significant abilities in sensation, awareness, integration of information, long-term memory, and adaptive learning, we must at least leave open the possibility that intelligence is certainly not unique to humans and probably not even to animals.
So whether you eat an animal or a plant, it may be time to acknowledge that both are sentient beings without one being more significant or important than the other, just different.
Natasha Longo has a master's degree in nutrition and is a certified fitness and nutritional counselor. She has consulted on public health policy and procurement in Canada, Australia, Spain, Ireland, England and Germany.