Trees of Life

A growing body of research on plant consciousness impacts current notions of ethics, nutrition and human survival

Published: 04th June 2023 05:00 AM | Last Updated: 01st June 2023 09:17 PM | A+A A-

"Tamasa bahuru’ona vestitah karmahetuna antahsanjña bhavantyate sukhadukha smarita"

Because of their evolutionary level, and specific methods of development, plants are unable to express themselves. But they possess internal sensitivity, feel pleasure and pain.

Manu Smriti (1:49)

The mystery of universal consciousness has taunted human knowledge for centuries. It has inspired legends and proved the Darwinian theory of evolution. It has influenced art and culture, customs, taboos, superstition, religion and science. As more revelations emerge from laboratories about man's role in the ecosystem, the results of myriad studies will impact current notions of ethics, nutrition, survival, compassion, human life and well-being.

Even as we search for evidence of life on other planets light-years away from Earth, closer home thrives a gigantic life system whose complexity is either ignored or unknown: plants.

Bioscience, a growing field of research, has entered unexplored dimensions, which question existing concepts of life, sustenance and understanding of existing species. The latest findings upend how we see ourselves:

● Major incremental evidence shows plants have consciousness● They feel pain and joy● They feel fear and anxiety in hostile circumstances● They communicate and have friends and defend against enemies

HEAR, HEARRecently, a team of evolutionary biologists at Tel Aviv University led by Prof. Lilach Hadany stirred up a storm by proving that plants cry for help when they are in danger. Using an ultrasonic microphone—a machine to record sound waves whose frequency is above 20 kHz; too high to be heard by the human ear—in a sound-proof chamber, the team recorded tobacco and tomato plants screaming in pain when distressed. They used punitive stimuli like dehydration, infections or wounds. Using AI, the scientists discovered that each plant and each type of stress produced different sounds as pops and clicks.

In normal conditions, the plants made less than one sound per hour, while dehydrated and injured ones made dozens of sounds. Water comprises about 80-95 percent of the fresh biomass of a plant. Once the dehydration peak was reached, Hadany noticed that the plants fell silent. They experimented with other forms such as corn, wheat, grape and cactuses as well. All responded in a similar fashion when they became anxious about being hurt or killed.

Israeli bio-scientist Simcha Lev-Yadun says when a plant is attacked by insects or mammals, it can differentiate between its foes through distinguishing factors such as mammalian saliva and insect chitin. "Accordingly, they up-regulate their specific defences," he says. In a paper published in 2019, Hadany established that plants respond to bees during pollination by opening their petals wider, indicating that the insect world can hear plant sounds. Her experiments were on sunflowers; when the buzz of the bee got closer, the plants responded "within three minutes by making sweeter nectar", she wrote.

Plants do not have a brain or a nervous system in the conventional sense, but neurobiology research shows that plant cells communicate with each other by generating bio-electricity like humans use neurons. They employ glutamate, the same chemical neurotransmitter used by human nerve cells. Italian botanist Stefano Mancuso, a professor of the Agriculture, Food, Environment and Forestry Department at the University of Florence, concluded that plants possess 15 additional senses along with the five known ones. Research has found that they can recognise their relatives: a 2007 study on plant kinship showed that potted plants grew bigger roots to compete with others around and cooperate mutually, which indicate that they are capable of making individual decisions.

In short, science proves that plants are sentient beings. They can hear things through vibrations; recorded sounds of chewing were enough for them to discharge protective chemicals. In a 2015 paper, named Effect of Music on Plants, authors Anindita Roy Chowdhury and Anshu Gupta summarised that harmonious music encouraged germination and growth of plants while heavy metal inhibited it.

"Previous research has investigated how plants respond to acoustic energy, including music," Heidi Appel, a 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 the University of Missouri, told Insider magazine. Plants have been proven to initiate root movements towards moisture simply by detecting vibrations of water moving inside underground pipes. They have the power of sight as well; they see using photosynthesis by sensing light emitted by other objects and beings.

MAYDAY, MAYDAYIn early May, Suzanne Simard, professor of forest ecology at the University of British Columbia, found that trees communicate with neighbouring ones using an extensive subterranean network of fungi. This grid resembles the human brain's neural networks. Using advanced equipment, she recorded chemical warning signals sent by an injured Douglas pine—a North American tree generally used as Christmas trees among other things—to another tree close by.

The alerted tree immediately produced defence enzymes to protect itself against the disease-causing insects that had infected the pine. Telengana-based Suresh Iyer, farmer, curator and life coach, elaborates, "Xylem, a type of tissue in vascular plants, which transports water from roots, is known to break under stress. Plants are intelligent in their own way, otherwise, how will they grow? How will photosynthesis take place? How will they know which nutrients to take from the soil and water? The difference is that they aren't as articulate as humans." Simard realised that the trees were sharing "information that is important to the health of the whole forest".

A study by University of Missouri researchers found that plants can even sense when they are being eaten, and discharge mechanisms to try to prevent the danger. Studies on their memory are ongoing; in an experiment, a man killed a plant by kicking and stomping on it in the presence of another plant. Subsequently, he asked a group of six people, including the ‘killer’, to pass by the surviving plant. It exhibited signs of extreme stress in his presence.

Says Hyderabad-based Kamlesh Patel aka ‘Daaji’, spiritual guide of Heartfulness Mediation Worldwide: "The physical and subtle bodies of plants are more closely bound than in animals, and the more evolved the animal, the greater that separation can be. Lesser the tethering, the more possibility of pain in death. So even though there is evidence that plants feel pain, that pain will be far lesser than what animals feel, because of the degree of binding of their subtle bodies."

NOURISH OR PERISHCharles Darwin may be unpopular with current Indian nationalist academia, but he did various experiments with tropism—the turning of all or part of an organism in a particular direction in response to an external stimulus—which he recorded in The Power of Movement in Plants and established the propensity of vegetation towards the source of life-giving energy. A recording apparatus, which legendary Indian scientist Sir Jagdish Chandra Bose invented to gauge a plant's heliotropic movements, found that if the light was applied to one side of a sunflower, the opposite side became rigid due to fluid pressure. Plants adopt different positions at day and night: their sleep is termed nyctinasty. Darwin believed that the embryonic root that emerges from the seed receives "impressions from the sense organs and directs movements".

Simard discovered that trees can share nutrients during a crisis such as drought to keep each other healthy. The vegetal forest community has guardians, akin to the ancient, wise figures of mythology. Just like tribal societies, all forests have venerable trees known as ‘mother trees’, which link all the trees in them. "In connecting with all the trees of different ages, the mother trees can facilitate the growth of these seedlings, which then link into the network of the old trees and benefit from that resource capacity. The old trees also pass a bit of carbon, nutrients and water to the seedlings at crucial times that help them survive," she said in a podcast.

Understanding nature is the pivot of human survival. Under your feet is a vast network of root communication that German forester Peter Wohlleben called the ‘woodwide web’. Trapped in the soil between roots is a fungal network called mycelium, which comprises minuscule ‘threads’. This is called a mycorrhizal network, which connects individual plants to transfer water, nitrogen, carbon and other minerals. Comprehending the functioning of this matrix can be beneficial to human survival.

According to Dr Kulbhushan Bhatt, founder of Sompanne, Delhi, "Understanding how plants interact can be harnessed in agricultural practices to improve crop yields and reduce the need for pesticides. By utilising the learning from natural guild, farmers can implement strategies that exploit the natural defence mechanisms of plants, reducing the use of chemicals and promoting sustainable practices." Similarly, the discovery of mycorrhizal networks has implications for forest conservation. Recognising the interconnectedness of trees in nutrient-sharing can help management practices that prioritise maintaining healthy and diverse forests, as well as protecting old-growth forests that serve as critical hubs for these networks.

ANCIENT FINDINGSCurrent findings confirm what Bose discovered over a century ago. They affirm that Indian science was far ahead of its time, and Western knowledge systems are acknowledging the fact slowly. Sometime in 1914, at a private laboratory in Maida Vale, London, a group of scientists watched Bose strap an object to the table of a vivisector—an apparatus used to dissect the live body of an animal during an experiment.

A highly sensitive lever was attached to the straps that could record electric impulses of pain. Bose pinched it with a pair of forceps. It recoiled. Only, the creature was not an animal; it was a humble carrot. A reporter from The Nation newspaper, who witnessed the experiment, wrote, "Thus can science reveal the feelings of even so stolid a vegetable as the carrot." Bose's first experiments went to proving plants had life. Playwright and Nobel Prize winner George Bernard Shaw, who was a vegetarian, is said to have wept during one of Bose's experiments: using a crescograph, a machine he invented, the scientist was able to record screams of agony of a fresh cabbage while it was being boiled in water. Bose believed that plants possessed a nervous system similar to animals, whose responses to external stimuli could be measured and recorded on light plates. He demonstrated at the Royal Society of London in 1901 that the pulse beat of a plant dipped in poison became unsteady once it started to absorb the bromide solution.

Sumana Roy, associate professor of English and creative writing at Ashoka University and author of How I Became a Tree, insists that the Western scientific community doesn't give Bose his due. She laments, "His research was suppressed and even mocked by a few scientists in North America as new work by the Scientific American now tells us. There were several reasons for this, primary among them being racist and ‘casteist’ (Bose's word to describe the system) science institutionalism. The fact that the new research does not cite his work is a continuation of that historical blindness to scientific work from the non-European and non-American world." As ancient Indian factology and scientific discoveries are being rediscovered by Western scientists, new realms are opening up regarding the mysteries of the universe, life, death and regeneration. Says Dr Binish Desai, Chairperson of Recycling at ESRAG (Environmental Sustainability Rotary Action Group) in South Asia, Gujarat: "We’ve always known that the food we eat or the air we breathe has living organisms. New studies on plants feeling fear and pain have forced us to take a serious look at the use of pesticides and its effects on health and the environment."

The Indian scriptures mention sentience in plants centuries ago. From the first to the 15th century, philosophers expounded that plants are sentient beings, though their faculties are dormant, dull and stupefied. The Rig Veda and Atharva Veda note consciousness in plants. The Ajivika guru Gosala wrote that they can sense touch, a premise echoed ages later by Israeli plant biologist Lev-Yadun, who also asserts that plants have sight, hearing, smell and taste. Experiments by Buddhist monk Gunaratna on Mimosa pudica (lajwanti) proved that plants are sapient like humans; a theory which was later explored by Udnacharya in the 10th century, and Sankaramisra in the 15th century. Like Gunaratna, Bose too mainly experimented on Mimosa pudica. His studies proved that plants’ response to various external stimuli was electrical, rather than chemical as was previously believed.

Dr Shweta Rana, Associate Professor, biology and environmental studies, FLAME University, Pune says, "Plants do feel and express emotions as established in the field of plant neurobiology. Many components of their neuronal system are similar to the ones in animals."

MORAL CONSEQUENCESThe ethical and spiritual conflict between meat-eating and vegetarianism is a hotly debated topic since the industrialisation of livestock rearing. "The morality aspect of consuming plants and vegetables that experience pain and stress is simple: it's wrong and cruel, but I don't think there is a simple solution. It doesn't make vegetarians better than non-vegetarians," explains Dr Desai.

Is the plant world in peril from human exploitation? Information garnered from published research, international databases and museum specimens establishes that 571 species have gone extinct in the past 250 years, though three-quarters of the world's food comes from just 12 plants. Says Daaji: "The future of the food industry lies not in stopping or encouraging the consumption of plant-based foods because they feel pain; it rests in evolving our state of being where we reduce the perils of pollution. It is for humanity to coexist with the natural world in a symbiotic manner." Will studies like Hadany and Simard's be suppressed? Roy doesn't think so. "It is because of a combination of things: the laboratories where this research has been conducted are in Europe and America; academia has moved towards what is being called ‘the vegetal turn’—so the scientific research will feed this impulse of humanity. But Bose will continue to remain uncited, such is the destiny of scientists from the non-Western world."

Even though the world ecosystem is facing a crisis of existence, the survival of the fittest theory has never been so relevant. History shows that plants always win in the end. Ancient forests and trees have outlasted not only civilisations but also species. The oldest known living non-clonal organism on Earth, the Great Basin bristlecone pine in Nevada, nicknamed Methuselah, is 5,000 years old. The age of Pando, a colony of 48,000 quaking aspen trees in Utah, is about 14,000 years old. It is believed that life originated in the primeval swamp as expostulated by Darwin; the existence of 3.4 billion-year-old fossils have proved that life began after the Earth was formed about 4.5 billion years ago. Plants existed much before humans appeared on Earth. They couldn't have survived without intelligence and adaptation. German psychologist Gustav Fechner even suggested that they have a soul. The Bhagavad Gita says, "In all species of life, as many forms are there, so the spirit soul is there." Knowledge enriches the spirit of human existence. And plants form the soul of life.

New shoots: what studies say

● A recent study by a team of evolutionary biologists at Tel Aviv University led by Prof. Lilach Hadany shows that plants cry for help when in danger.● Israeli bio-scientist Simcha Lev-Yadun says when attacked by insects or mammals, plants can differentiate between foes through factors such as mammalian saliva and insect chitin.● A 2007 study on plant kinship showed that potted plants grew bigger roots to compete with others around and cooperate mutually, which indicates that they are capable of making individual decisions.● Effect of Music on Plants, a paper published in 2015 by authors Anindita Roy Chowdhury and Anshu Gupta, showed that harmonious music encouraged the growth of plants while heavy metal inhibited it.

Songs of the soil

Plant choirA small, durable bluetooth device that uses the biorhythmic feedback of the plant's energy and translates it into music. Once the device is connected to the plant, you can hear the music on the plantchoir app on your phone

Plants PlayFounded by an Italian couple, Edo and Kika, the portable device can be worn around the neck. You can listen to the music of any plant by plugging one end of the sensors into the jacks, and the other end on the leaves

Music of the PlantsThe device creates the sound of plants, once you attach one electrode to a damp leaf, and the other into the soil. Made of bamboo, which has natural amplification qualities, these devices also work as speakers for plant music.

Plant WaveA small rectangular device, which picks up on the change in the electrical charges in a plant through the electrode leads placed on the leaf, and translates it into music

For all devices, you can choose the instrument, bass, and themes to listen to the plant music in the way you like; all apps available on Android and iOS

With Ayesha Singh