Plant Senses
Duration: 4 hours
Target Audience: Anyone who is interested in science, life, joy, nature and the cosmos
Brief:
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Plants have perceptions. They sense the environment and adjust their morphology, physiology and phenotype accordingly. They can they see, smell, taste, feel, listen, talk, think, count, travel, fight, kill, climb, make decisions, cope with stress, and love. Examples of stimuli which plants perceive and can react to include chemicals, gravity, light, moisture, infections, temperature, oxygen and carbon dioxide concentrations, parasite infestation, physical disruption, sound, and touch. Plants have a variety of means to detect such stimuli and a variety of reaction responses or behaviors.
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Stomata in the leaf can react to the intensity and the quality of light. The stomata can detect the chemical nature of the atmosphere, responding to levels of carbon dioxide and other gases. They to respond to physical stimuli that affect the leaf, like vibrations and movement caused by wind.
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Wounded tomatoes are known to produce the volatile odor methyl-jasmonate as an alarm-signal. Plants in the neighborhood can then detect the chemical and prepare for the attack by producing chemicals that defend against insects or attract predators.
Plants systematically use hormonal signaling pathways to coordinate their own development and morphology. Plants produce several proteins found in the animal neuron systems such as acetylcholine esterase, glutamate receptors, GABA receptors, and endocannabinoid signaling components. |
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Although plant cells are not neurons, they can be electrically excitable and can display rapid electrical responses (action potentials) to environmental stimuli. These action potentials can influence processes such as actin-based cytoplasmic streaming, plant organ movements, wound responses, respiration, photosynthesis, and flowering. These electrical responses can cause the synthesis of numerous organic molecules, including ones that act as neuroactive substances in other organisms. Thus, plants accomplish behavioral responses in environmental, communicative, and ecological contexts.
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Plants have the ability to detect an electrical field. There has long been a belief that a lawn becomes greener before the torrential downpour of a thunderstorm. Experiments were carried out where high-tension cables were stretched across a field of growing crops. The results showed that the plant did indeed 'green up' in response to an electrical field. During the 1990s, research at Imperial College, London, located sensory cells within the plant which have the ability to sense electricity. It is true that the plants really do "green up" in thundery weather before the rain starts.
A plant's concomitant reactive behavior is mediated by phytochromes, kinins, hormones, antibiotic or other chemical release, changes of water and chemical transport, and other means. |
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Plants have many strategies to fight off pests. For example, they can produce different toxins against invaders or they can induce rapid cell death in invading cells to hinder the pests from spreading out. Some plants are capable of rapid movement: the mimosa plant makes its thin leaves point down at the slightest touch and carnivorous plants such as the Venus flytrap snap shut by the touch of insects. In plants, the mechanism responsible for adaptation is signal transduction.
Adaptive responses include:
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Plants have a vast vocabulary of signals and responses. They can detect the signs of a change in their environment and adjust their metabolism to anticipate its effects. They have finely tuned senses for signs of environmental stress which can compensate for its effects.
