Plant perception (physiology)
Encyclopedia
In the study of plant physiology
Plant physiology
Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology , plant ecology , phytochemistry , cell biology, and molecular biology.Fundamental processes such as photosynthesis, respiration, plant nutrition,...

 plant perception is a term used to describe mechanisms by which plants recognize changes in the environment. Examples of stimuli which plants perceive and can react to include chemicals, gravity, light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

, moisture
Moisture
Humidity is the amount of moisture the air can hold before it rains. Moisture refers to the presence of a liquid, especially water, often in trace amounts...

, infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

s, temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

, oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 and carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 concentrations, parasite infestation, physical disruption, and touch. Plants have a variety of means to detect such stimuli
Stimulus (physiology)
In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....

 and a variety of reaction responses or behavior
Behavior
Behavior or behaviour refers to the actions and mannerisms made by organisms, systems, or artificial entities in conjunction with its environment, which includes the other systems or organisms around as well as the physical environment...

s.

Plant perception occurs on a cellular level and its concomitant reactive behavior is mediated by phytochrome
Phytochrome
Phytochrome is a photoreceptor, a pigment that plants use to detect light. It is sensitive to light in the red and far-red region of the visible spectrum. Many flowering plants use it to regulate the time of flowering based on the length of day and night and to set circadian rhythms...

s, kinin
Kinin
A kinin is any of various structurally related polypeptides, such as bradykinin and kallikrein. They are members of the autacoid family.They act locally to induce vasodilation and contraction of smooth muscle.It is a component of the kinin-kallikrein system....

s, hormones
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...

, antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...

 or other chemical release, changes of water and chemical transport, and other means. These responses are generally slow, taking at minimum a number of hours to accomplish, and can best be observed with time-lapse
Time-lapse
Time-lapse photography is a cinematography technique whereby the frequency at which film frames are captured is much lower than that which will be used to play the sequence back. When replayed at normal speed, time appears to be moving faster and thus lapsing...

 cinematography, but rapid movements
Rapid plant movement
Rapid plant movement encompasses movement in plant structures occurring over a very short period of time, usually under one second. For example, the Venus Flytrap closes its trap in about 100 milliseconds. The Dogwood Bunchberry's flower opens its petals and fires pollen in less than 0.5 milliseconds...

 can occur as well.

Research published in September 2006 has shown, certainly in the case of Arabidopsis thaliana
Arabidopsis thaliana
Arabidopsis thaliana is a small flowering plant native to Europe, Asia, and northwestern Africa. A spring annual with a relatively short life cycle, arabidopsis is popular as a model organism in plant biology and genetics...

, the role of cryptochrome
Cryptochrome
Cryptochromes are a class of blue light-sensitive flavoproteins found in plants and animals. Cryptochromes are involved in the circadian rhythms of plants and animals, and in the sensing of magnetic fields in a number of species...

s in the perception of magnetic fields by plants.

Senses in plants

Plants have many strategies to fight off pests. For example, they can
produce different toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...

s (so called phytoalexin
Phytoalexin
Phytoalexins are antimicrobial substances synthesized de novo by plants that accumulate rapidly at areas of incompatible pathogen infection. They are broad spectrum inhibitors and are chemically diverse with different types characteristic of particular plant species...

s) against invaders or they
can induce rapid cell death of invaded cells to hinder the pests from
spreading out. All these strategies depend on quick and reliable
recognition-systems. Research of the last years revealed some amazing
abilities of plants in this area. Plants not only can taste the spit of
caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...

s, they can also smell, see, "feel" and hear, as Andy Coughlin
reported in the New Scientist
New Scientist
New Scientist is a weekly non-peer-reviewed English-language international science magazine, which since 1996 has also run a website, covering recent developments in science and technology for a general audience. Founded in 1956, it is published by Reed Business Information Ltd, a subsidiary of...

 (26/9.98).

Smell

Wounded tomatoes are known to produce the volatile odour
methyl jasmonate as an alarm-signal. Plants in the neighbourhood can then
smell the danger and prepare for the attack by producing chemicals that
defend against insects or attract insectivorous predators. And according to New Scientist:
"Methyl jasmonate is often used in perfumes and this created problems for
the researchers." "We had to warn the women not to use it in the greenhouse
because it would mess up the experiment", said Bud Ryan (Washington State University
Washington State University
Washington State University is a public research university based in Pullman, Washington, in the Palouse region of the Pacific Northwest. Founded in 1890, WSU is the state's original and largest land-grant university...

).

Light and Electromagnetic waves

Many plant-organs contain photosensitive compounds, each
reacting very specifically to certain wavelengths of light. These
light-sensors tell the plant if it's day or night, how long the day is,
how much light is available and from where the light comes. More recently,
researchers discovered that plants also can detect harmful ultraviolet B-rays and then start producing pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

s which filter out these rays.
"Plants make their own suntan cream in the presence of UVB", says Gareth Jenkins (University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

).

Touch

Many of us are familiar with the mimosa plant (Mimosa pudica
Mimosa pudica
Mimosa pudica , is a creeping annual or perennial herb often grown for its curiosity value: the compound leaves fold inward and droop when touched or shaken, re-opening minutes later...

);
it makes its thin leaves point down at the slightest touch. And carnivorous plant
Carnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...

s such as the Venus flytrap
Venus Flytrap
The Venus Flytrap , Dionaea muscipula, is a carnivorous plant that catches and digests animal prey—mostly insects and arachnids. Its trapping structure is formed by the terminal portion of each of the plant's leaves and is triggered by tiny hairs on their inner surfaces...

 snap shut by the touch of insects. But a
sense of touch is something every plant has, as Coughlin describes:
"Ordinary plants need a sense of touch to respond to the buffeting of the
wind, which can cause damage to foliage. They try to resist wind by
strengthening tissues that are being swayed. The extra energy expended
stiffening tissue can cost farmers dear, however. One experiment showed
that when maize plants are shaken for 3 seconds each day, yields drop by
30 to 40% compared with unshaken plants", writes Coughlin (New Scientist).

Sound

Mordecai Jaffe (Wake Forest University
Wake Forest University
Wake Forest University is a private, coeducational university in the U.S. state of North Carolina, founded in 1834. The university received its name from its original location in Wake Forest, north of Raleigh, North Carolina, the state capital. The Reynolda Campus, the university's main campus, is...

) used an
instrument that made a loud "warble" and got a doubling in the growth of
dwarf pea plants. Jaffe suspects that the plant hormone
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...

 gibberellic acid
Gibberellic acid
Gibberellic acid Gibberellic acid Gibberellic acid (also called Gibberellin A3, GA, and (GA3) is a hormone found in plants. Its chemical formula is C19H22O6. When purified, it is a white-to-pale-yellow solid....

,
which is instrumental in shoot
Shoot
Shoots are new plant growth, they can include stems, flowering stems with flower buds, and leaves. The new growth from seed germination that grows upward is a shoot where leaves will develop...

 elongation and seed germination, is involved
in the "hearing" response. When Jaffe added chemicals to the pea plants
inhibiting the biosynthesis
Biosynthesis
Biosynthesis is an enzyme-catalyzed process in cells of living organisms by which substrates are converted to more complex products. The biosynthesis process often consists of several enzymatic steps in which the product of one step is used as substrate in the following step...

 of this hormone, he was unable to reproduce the
original effects.

See also

  • Auxin
    Auxin
    Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins have a cardinal role in coordination of many growth and behavioral processes in the plant's life cycle and are essential for plant body development. Auxins and their role in plant growth were first described by...

     - A plant hormone which mediates responses
  • Chemotropism
    Chemotropism
    Chemotropism is growth of organisms such as bacteria and plants, navigated by chemical stimulus from outside of the organism....

     - Plant response to chemicals
  • Cryptochrome
    Cryptochrome
    Cryptochromes are a class of blue light-sensitive flavoproteins found in plants and animals. Cryptochromes are involved in the circadian rhythms of plants and animals, and in the sensing of magnetic fields in a number of species...

     - A light receptor pigment
  • Ethylene
    Ethylene
    Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...

     - A plant hormone which mediates responses
  • Gravitropism
    Gravitropism
    Gravitropism is a turning or growth movement by a plant or fungus in response to gravity. Charles Darwin was one of the first to scientifically document that roots show positive gravitropism and stems show negative gravitropism. That is, roots grow in the direction of gravitational pull and stems...

     - Behavior associated with gravitic perception
  • Heliotropism
    Heliotropism
    Heliotropism is the diurnal motion of plant parts in response to the direction of the sun.It is found in some members of family Malvacea e.g Malva or Lavetara...

     - Behavior associated with sunlight perception
  • Hormonal sentience
    Hormonal sentience
    Hormonal sentience, first described by Robert A. Freitas Jr., describes the information processing rate in plants, which are mostly based on hormones instead of neurons like in all major animals...

     - Plant information processing theory
  • Hydrotropism
    Hydrotropism
    Hydrotropism is a plant's growth response in which the direction of growth is determined by a stimulus or gradient in water concentration...

     - Plant response to moisture
  • Hypersensitive response
    Hypersensitive response
    The hypersensitive response is a mechanism, used by plants, to prevent the spread of infection by microbial pathogens. The HR is characterized by the rapid death of cells in the local region surrounding an infection. The HR serves to restrict the growth and spread of pathogens to other parts of...

     - Local reaction produced in response to infection by microbes
  • Kinesis (biology) - Movement
  • Nastic movements
    Nastic movements
    Nastic movements are non-directional responses to stimuli . The movement can be due to changes in turgor or changes in oma. Nastic movements differ banaan tropic movements in that the direction of tropic responses depends on the direction of the stimulus, whereas the direction of nastic movements...

     - A type of rapid response to non-directional stimulus
  • Osmosis
    Osmosis
    Osmosis is the movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, aiming to equalize the solute concentrations on the two sides...

     - A means of water transportation on the cellular level
  • Phototropin
    Phototropin
    Phototropins are photoreceptor proteins that mediate phototropism responses in higher plants. Along with cryptochromes and phytochromes they allow plants to respond and alter their growth in response to the light environment...

     - A light receptor pigment
  • Phototropism
    Phototropism
    Phototropism is directional growth in which the direction of growth is determined by the direction of the light source. In other words, it is the growth and response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi...

     - A behavior associated with light perception
  • Phytochrome
    Phytochrome
    Phytochrome is a photoreceptor, a pigment that plants use to detect light. It is sensitive to light in the red and far-red region of the visible spectrum. Many flowering plants use it to regulate the time of flowering based on the length of day and night and to set circadian rhythms...

     - A light receptor pigment
  • Phytosemiotics
    Phytosemiotics
    Phytosemiotics is a branch of biosemiotics that studies the sign processes in plants, or more broadly, the vegetative semiosis. Vegetative semiosis is a type of sign processes that occurs at cellular and tissue level, including cellular recognition, plant perception, plant signal transduction,...

     - Analysis of vegetative processes on the basis of semiotic theory
  • Plant defense against herbivory
    Plant defense against herbivory
    Plant defense against herbivory or host-plant resistance describes a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores. Plants use several strategies to defend against damage caused by herbivores...

     - Some plant responses to physical disruption
  • Plant hormone
    Plant hormone
    Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...

     - A mediator of response to stimuli
  • Plant intelligence
    Plant intelligence
    In botany, plant intelligence is the ability of plants to sense the environment and adjust their morphology, physiology and phenotype accordingly...

  • Plant physiology
    Plant physiology
    Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology , plant ecology , phytochemistry , cell biology, and molecular biology.Fundamental processes such as photosynthesis, respiration, plant nutrition,...

     - The science of plant function
  • Rapid plant movement
    Rapid plant movement
    Rapid plant movement encompasses movement in plant structures occurring over a very short period of time, usually under one second. For example, the Venus Flytrap closes its trap in about 100 milliseconds. The Dogwood Bunchberry's flower opens its petals and fires pollen in less than 0.5 milliseconds...

     - Description of rapid plant movements
  • Sensory receptors - Discussion of organs of perception in organisms
  • Statolith - An organ of gravity perception
  • Stoma
    Stoma
    In botany, a stoma is a pore, found in the leaf and stem epidermis that is used forgas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening...

     - A plant pore which responds to stimulus and which regulates gas exchange
  • Systemic acquired resistance
    Systemic acquired resistance
    The systemic acquired resistance is a "whole-plant" resistance response that occurs following an earlier localized exposure to a pathogen. SAR is analogous to the innate immune system found in animals, and there is evidence that SAR in plants and innate immunity in animals may be evolutionarily...

     - A "whole-plant" resistance response to microbial pathogens that occurs following an earlier, localized response
  • Taxis
    Taxis
    A taxis is an innate behavioral response by an organism to a directional stimulus or gradient of stimulus intensity. A taxis differs from a tropism in that the organism has motility and demonstrates guided movement towards or away from the stimulus source ...

     - A type of response to a directional stimulus seen in motile developmental stages of lower plants
  • Thermotropism
    Thermotropism
    Thermotropism or thermotropic movement is the movement of a plant or plant part in response to changes in temperature. A common example is the curling of Rhododendron leaves in response to cold temperatures.-External links:*...

     - Plant response to heat
  • Thigmotropism
    Thigmotropism
    Thigmotropism is a movement in which an organism moves or grows in response to touch or contact stimuli. The prefix thigmo- θιγμος comes from the Greek for "touch". Usually thigmotropism occurs when plants grow around a surface, such as a wall, pot, or trellis. Climbing plants, such as vines,...

     - Plant response to touch
  • Tropism
    Tropism
    A tropism is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus. In tropisms, this response is dependent on the direction of the stimulus...

    - A type of response to a directional stimulus

External links

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