Do Plants feel hungry?

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To answer the question if plants feel hungry, let us first understand what we mean by hunger and hungry. Oxford dictionary defines hunger as "A feeling of discomfort or weakness caused by lack of food, coupled with the desire to eat" and hungry as "Feeling or showing the need for food." We feel hungry because we need energy for carrying out our daily activities. We feel hungrier especially after strenuous physical activities like indulging in a sport or mental activities like intense reading/thinking. Energy is obtained from the food we eat that is chemically by breaking down the bonds between two atoms in a molecule/compound that make up our food. We are heterotrophs and we depend on plants enormously for our nutritional requirements. Plants are autotrophs which can synthesize food/organic molecules on their own which we consume. What does energy have to do with being alive? Because, each cell that we are made up of needs energy primarily to maintain itself in its orderly state, to carry-out its function and also to replicate. What does it mean to be in an orderly state for a cell? ‘Order’ in cells originates from the organisational structure of its components and the composition of the elements that make those structures.

Cells are made of the same elements that make up the earth's crust. But the composition of elements relative to each other is quite different from their environment. The proportion of each of the elements are starkly different between what is found on earth's surface and that of the human body. Natural forces (physical forces and the activities of organisms themselves) tend to bring the composition of the elements that make up the human body to equilibrium with its surrounding. But the cells in the body resist those forces to retain their status quo by expending energy. Therefore, life is an activity devoted enormously to resisting the forces of nature by harnessing and using energy! An organism is dead once it cannot gather energy external to it and use it. Therefore, it decays over time and the composition of its elements gradually attains equilibrium with that of the surroundings. Now, let's return to our question about hunger.

When we say that we feel hungry, we refer to the feeling arising in our stomach. We should also understand that the feeling of hunger is felt by the brain, but felt in the stomach! Brain and stomach are distinct organs that cater to specific functions; stomach to digest food and absorb nutrients, and brain to sensing different stimuli and regulating body's response to them. Plants do not have stomach and brain. They possess, relative to animals, a much decentralized system of regulating biological processes. Except for a few requirements, such as the need for water and nutrients by aerial plant parts and for synthesized organic molecules by roots, organs of plants are quite independent in meeting their needs. Plants do not depend on complex organic compounds to sustain their life and reproduce; they synthesize their requirement of complex organic compounds—the source of energy and building blocks—from simpler molecules using energy from solar radiation. That is, they are phototrophs. If plants can synthesize their own food, would they feel the hunger? Therefore, can we not conclude that plants may not feel hungry in the same way as animals, as each of their needs and senses are different? I must say yes.

Considering that the biological system of plants is quite disparate from that of animals, it may not be the appropriate question to ask if plants feel hunger the same way as animals do. But, by trying to think and talk about it, we have arrived at a conclusion that the question should be different with respect to plants. It could be regarding their reaction to dearth of water, sunlight and nutrients which they depend on for their life. You can think about it, ask a different question and go through the process of discussion about that question. If you find that the question is relevant, plan experiments that shall answer your question. Experiments there should negate the possibility of any alternative explanation. That's doing science. Finding facts of life, the ‘how’ and the ‘why’ of the world, animate and inanimate, around us.

 

Article by:

Velu Mani Selvaraj

Research Scholar

University of Hyderabad, Hyderabad

ICAR-Indian Institute of Oilseeds Research, Hyderabad

Email: getvelumani@gmail.com