Feeling For Plants

By Subhayu Mazumder
How does it feel? It’s a common enough question but, answered truthfully, is capable of peering into the depths of the soul. How did you feel while watching the new movie at the multiplex? Sad? Happy? Excited? Afraid? Or were you bored? What about while reading the last book you picked up online? Were you curious, anxious, sad...or did the ending surprise you? What about the time you found a long-lost friend on Facebook? Weren’t you ecstatic, nostalgic, euphoric, and maybe even a little remorseful that you hadn’t kept in touch since school? The point is, almost ALL spheres of human activity evoke feelings. To tweak Descartes’ famous proposition a little, you could almost say that humans are, therefore they feel.
The reason, as we know, is humans are sentient beings — capable of rational, objective thought and also of highly subjective ideas and feelings. And that holds true of most other members of the animal kingdom as well. But what about the plant kingdom? Is it so preposterous to suggest that plants are also capable of emotion? That is exactly what a team of scientists at the Bose Institute in Kolkata aim to find out. The idea that plants can feel emotions is not a new one. After the idea was first proposed in 1848 by German experimental psychologist Gustav Theodor Fechner, Sir Jagadish Chandra Bose, the Indian polymath — physicist, biologist, botanist, archaeologist and early writer of science fiction — began to conduct his own experiments in 1900 and drew some startling inferences. In the 1960s, former CIA agent Cleve Backster conducted his own experiments by exposing plants to certain stimuli and measuring readings on a polygraph (lie-detector).
The authors of the 1974 book ‘The Secret Life of Plants’ — Peter Tompkins and Christopher Bird — also drew inspiration from Bose’s research and expanded on the idea, but their work was dismissed as pseudoscience. Interestingly, most research of note — scientific or pseudoscientific, we’re not judging here — on plants-as-sentient-creatures trace their roots to Bose’s pioneering work. It is, then, only fitting that the team of scientists that hopes to complete and carry his work forward should choose to run their research at the institute the great scientist had founded in the city and call it, although informally, the JC Bose Legacy Project. “There is no project that’s officially called the JC Bose Legacy Project,” clarifies Sonali Sengupta, staff scientist, supported by the department of biotechnology, government of India, and a Young Scientist, department of science and technology. “We have a lot of moving and responding plants on our Madhyamgram campus, such as the sensitive lajjabati (Mimosa pudica) and boncharal (Desmodium gyrans), that show different response to external stimuli, such as touch, light or noise. Our interest piqued, Professor Arun Lahiri Majumder and I decided to start work on the molecular mystery of these plants. We were eager to figure out what the environmental sensors in these plants are, in terms of proteins and genes.”
In 2013, the prestigious American Society of Plant Biology invited Sengupta for a talk on the research. More recently, Sengupta’s and Lahiri Majumdar’s work on plant response was nominated for presentation at the Gordon Research conferences this August at Maine, the US, that cover frontier research in the biological, chemical and physical sciences and their related technologies. What did Bose achieve through his experiments, and how has the ‘Legacy Project’ built upon that work? In the early 20th century, when Bose had started out on his work in plant biology, plants were not regarded to be living and responding entities of the same class as animals. “But through his work, Bose established that plants respond to stimuli and they may even modulate the degree of their response, depending on the degree of stimulation.” She goes on to explain why the finding was so exciting. “This is comparable to the response of a human being. For example, we can listen to a certain amount of loud noise without perceptible reaction, and when the noise becomes too loud, we have two options — either to cover our ears, or to run away from the noise. Plants cannot run away. But they respond in various other ways — the root or shoot bends away or towards the stress factor. Plants, thus, have the power to re-module their growth plans. Bose established that plants are responsive living creatures.”
Bose’s work, Sengupta adds, has been extended to much more molecular detailing in various countries, but a crucial aspect of the work currently being done by the Legacy project — proteomic and genomic identification of touch sensors — has not been done anywhere else. “We know how a sensitive plant moves when touched, but we don’t know why it moves, and we don’t know where the molecular events start. Our research aims at that point. It has definitely gone further, but the pivotal questions remain unanswered.” So, how does one define “feelings” in plants? Also, should we be delineating plants’ emotions in animal (or human) terms in the first place? “It’s difficult to define ‘feeling’ in plants, as its meaning — for example, fear, shame, anger, happiness — is delimited by human behaviour,” Sengupta clarifies.
“These are human feelings, and their names are human constructs. However, each feeling has a specific chemical reaction (or reactions). For plants, feelings may come from a different perspective, and it is difficult to define them in terms that we would easily understand.” “We noticed an interesting thing that the Cuscuta (Swarnalata) plant does. The chlorophyll-less plant, which needs a green host to survive, often moves away from a host if it detects that there is another Cuscuta plant feeding off it. It then begins to search for another host. This is complex behaviour; it is highly adaptive, like any other human behaviour, and can be broken into a cascade of molecular reactions... but it is difficult to name. It is a physiological reaction, but it involves creation of first memories, sense of direction, discrimination between self and non-self and command over self. In this context, it is imperative to understand that feelings are physiological, too. In our research, we do not assume that plants have feelings parallel to that of humans. But we propose that plants receive environmental perturbations and respond to those all the time, and they may have plant-specific ‘feelings’.”
This, of course, begs the question — how exactly are the feelings of plants different from that of animals? “Frankly, we don’t know, and that’s something we would very much like to know,” says Sengupta. “It has not yet been proved that plants have feelings similar to that of humans. We prefer to say that plants are ‘active responders’ of sensory stimulation. Their ‘feelings’, if at all there are any, would very much be need-driven. Anthropocentric emotions would not be their way of life, although they may show kin-selection and interdependence. In simpler words, we have to learn the language of plants to know how they feel… and, possibly, define their feelings in that language, if possible.” Okay, maybe plants have feelings... what next? Why is this important? It turns out that this research could have extremely important technological impact.
“If we can understand the actual reactions that take place in a plant body when it ‘feels’ certain ‘emotions’ and the kinds of stimuli that are bringing these about — drought, salinity, temperature, cold or animals’ grazing, we have the potential to greatly manipulate agriculture and forestry, and even contribute to global food security,” says Sengupta. “Also, the rapid response of several plants to touch is one of our major areas of interest. If we can find the protein/proteins that give such rapid reaction, they may be engineered to create biosensors.” “But above all, we are simply thrilled that we are having a look inside a silent cell and trying to understand a plant from the plant’s context... just like J C Bose did more than 100 years ago,” Sengupta signs off.