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Many plant-organs contain photo-sensitive compounds ([[phototropin]]s, [[cryptochrome]]s and [[phytochrome]]s) 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 ([[photoperiodism]]), how much light is available and from where the light comes. Plants also can detect harmful ultraviolet B-rays and then start producing pigments which filter out these rays.<ref>Åke Strid and Robert J. Porra. [http://pcp.oxfordjournals.org/cgi/content/short/33/7/1015 Alterations in Pigment Content in Leaves of Pisum sativum After Exposure to Supplementary UV-B]. Plant and Cell Physiology, 1992, Vol. 33, No. 7 1015-1023</ref>
Many plant-organs contain photo-sensitive compounds ([[phototropin]]s, [[cryptochrome]]s and [[phytochrome]]s) 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 ([[photoperiodism]]), how much light is available and from where the light comes. Plants also can detect harmful ultraviolet B-rays and then start producing pigments which filter out these rays.<ref>Åke Strid and Robert J. Porra. [http://pcp.oxfordjournals.org/cgi/content/short/33/7/1015 Alterations in Pigment Content in Leaves of Pisum sativum After Exposure to Supplementary UV-B]. Plant and Cell Physiology, 1992, Vol. 33, No. 7 1015-1023</ref>


===Contact Stimuli===
===Contact stimuli===
{{Main|Thigmotropism|Thigmomorphogenesis}}
{{Main|Thigmotropism|Thigmomorphogenesis}}

The mimosa plant (''[[Mimosa pudica]]'') makes its thin leaves point down at the slightest touch and [[carnivorous plant]]s such as the [[Venus flytrap]] snap shut by the touch of insects. {{citation needed|date=November 2011}}
The mimosa plant (''[[Mimosa pudica]]'') makes its thin leaves point down at the slightest touch and [[carnivorous plant]]s such as the [[Venus flytrap]] snap shut by the touch of insects. {{citation needed|date=November 2011}}



Mechanical perturbation can also be detected by plants.<ref>{{cite doi|10.1007/BF00027213}}</ref> [[Jasmonate]] levels also increase rapidly in response to mechanical perturbations such as tendril coiling.<ref>{{cite doi|10.1007/BF00201050}}</ref>
Mechanical perturbation can also be detected by plants.<ref>{{cite doi|10.1007/BF00027213}}</ref> [[Jasmonate]] levels also increase rapidly in response to mechanical perturbations such as tendril coiling.<ref>{{cite doi|10.1007/BF00201050}}</ref>

Revision as of 19:31, 4 August 2012

Vine tendril. Note how the plant reaches for and purposely wraps around the galvanised wire provided for the purpose. This is a very tough twig and appears to have no other purpose than support for the plant. Nothing else grows from it. It must reach out softly, then wrap around and then dry and toughen. See more at thigmotropism.

In botany, plant intelligence is the ability of plants to sense the environment and adjust their morphology, physiology and phenotype accordingly.[1] Research draws on the fields of plant physiology, ecology and molecular biology.

Intelligence is an umbrella term describing abilities such as the capacities for abstract thought, understanding, communication, reasoning, learning, learning from past experiences, planning, and problem solving. Studies indicate plants are capable of problem solving and communication.

Problem solving

Plants adapt their behaviour in a variety of ways:

Communication

Plants respond to volatile signals produced by other plants.[9][10]

Mechanisms

Main articles: Signal transduction, Plant neurobiology, and Plant hormone

In plants, the mechanism responsible for adaptation is signal transduction.[11][12][13][14] Plants do not have a brain or neuronal network, but reactions within signalling pathways may provide a biochemical basis for learning and memory.[15] Controversially, the brain is used as a metaphor in plant intelligence to provide an integrated view of signalling,[16] (see plant neurobiology).

Plant cells 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.[17][18][19][20]

Plant perception

Main article: Plant perception (physiology)

Plants have many strategies to fight off pests. For example, they can produce different toxins (phytoalexins) against invaders or they can induce rapid cell death in invading cells to hinder the pests from spreading out. These strategies depend on quick and reliable recognition-systems.

Alarm signals

Wounded tomatoes are known to produce the volatile odour methyl-jasmonate as an alarm-signal.[21] Plants in the neighbourhood can then detect the chemical and prepare for the attack by producing chemicals that defend against insects or attract predators.[21]

Light

Main articles: Photomorphogenesis and photoperiodism

Many plant-organs contain photo-sensitive compounds (phototropins, cryptochromes and phytochromes) 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 (photoperiodism), how much light is available and from where the light comes. Plants also can detect harmful ultraviolet B-rays and then start producing pigments which filter out these rays.[22]

Contact stimuli

Main articles: Thigmotropism and Thigmomorphogenesis

The mimosa plant (Mimosa pudica) 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. [citation needed]

Mechanical perturbation can also be detected by plants.[23] Jasmonate levels also increase rapidly in response to mechanical perturbations such as tendril coiling.[24]

Poplar stems can detect reorientation and inclination (equilibrioception).[25]

Plant adaptation vs plant intelligence

It has been argued that although plants are capable of adaptation, it should not be called intelligence. "A bacterium can monitor its environment and instigate developmental processes appropriate to the prevailing circumstances, but is that intelligence? Such simple adaptation behaviour might be bacterial intelligence but is clearly not animal intelligence."[26] However, plant intelligence fits with the definition of intelligence proposed by David Stenhouse in a book he wrote about evolution where he described it as "adaptively variable behaviour during the lifetime of the individual".[27]

It is also argued that a plant cannot have goals because operational control of the plant's organs is devolved.[26]

History

Charles Darwin studied the movement of plants and in 1880 published a book The Power of Movement in Plants. In the book he concludes:

It is hardly an exaggeration to say that the tip of the radicle thus endowed [..] acts like the brain of one of the lower animals; the brain being situated within the anterior end of the body, receiving impressions from the sense-organs, and directing the several movements.

Indian scientist Sir Jagdish Chandra Bose began to conduct experiments on plants in the year 1900. He found that every plant and every part of a plant appeared to have a sensitive nervous system and responded to shock by a spasm just as an animal muscle does.[28][29]

Bose's experiments stopped at this conclusion, but American polygraph expert Cleve Backster conducted research that led him to believe that plants can communicate with other lifeforms.[30][31] Backster's interest in the subject began in February 1966, when Backster wondered if he could measure the rate at which water rises from a philodendron's root area into its leaves. Because a polygraph or "lie detector" can measure electrical resistance, and water would alter the resistance of the leaf, he decided that this was the correct instrument to use. After attaching a polygraph to one of the plant's leaves, Backster claimed that, to his immense surprise, "the tracing began to show a pattern typical of the response you get when you subject a human to emotional stimulation of short duration".

See also

References

  1. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/j.tplants.2005.07.005, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/j.tplants.2005.07.005 instead.
  2. ^ a b De Kroon, H. and Hutchings, M.J. (1995) Morphological plasticity in clonal plants: the foraging concept reconsidered. J. Ecol. 83, 143–152
  3. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1023/A:1019640813676, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1023/A:1019640813676 instead.
  4. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0065-2504(08)60215-9, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S0065-2504(08)60215-9 instead.
  5. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1126/science.199.4331.888, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1126/science.199.4331.888 instead.
  6. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.2307/1938905, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.2307/1938905 instead.
  7. ^ Attention: This template ({{cite jstor}}) is deprecated. To cite the publication identified by jstor:2389968, please use {{cite journal}} with |jstor=2389968 instead.
  8. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0065-2504(08)60032-X, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S0065-2504(08)60032-X instead.
  9. ^ Proc Natl Acad Sci U S A. 1990 October; 87(19): 7713–7716. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC54818/
  10. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1023/A:1007893626166, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1023/A:1007893626166 instead.
  11. ^ Scheel, Dierk; Wasternack, C. (2002). Plant signal transduction. Oxford: Oxford University Press. ISBN 0-19-963879-9.
  12. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1034/j.1399-3054.2001.1120202.x, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1034/j.1399-3054.2001.1120202.x instead.
  13. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 12194182, please use {{cite journal}} with |pmid=12194182 instead.
  14. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 10200239, please use {{cite journal}} with |pmid=10200239 instead.
  15. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 9888852, please use {{cite journal}} with |pmid=9888852 instead.
  16. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/j.tplants.2006.06.009, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/j.tplants.2006.06.009 instead.
  17. ^ Wagner E, Lehner L, Normann J, Veit J, Albrechtova J (2006). Hydroelectrochemical integration of the higher plant—basis for electrogenic flower induction. pp 369–389 In: Balusˇka F, Mancuso S, Volkmann D (eds) Communication in plants: neuronal aspects of plant life. Springer, Berlin.
  18. ^ Fromm J, Lautner S. (2007). Electrical signals and their physiological significance in plants. Plant Cell Environ. 30(3):249-57. doi:10.1111/j.1365-3040.2006.01614.x PMID 17263772
  19. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 19129416, please use {{cite journal}} with |pmid=19129416 instead.
  20. ^ Attention: This template ({{cite jstor}}) is deprecated. To cite the publication identified by jstor:4353850, please use {{cite journal}} with |jstor=4353850 instead.
  21. ^ a b E E Farmer and C A Ryan (1990-10-01). "Interplant communication: airborne methyl jasmonate induces synthesis of proteinase inhibitors in plant leaves". Pnas.org. Retrieved 2012-07-23.
  22. ^ Åke Strid and Robert J. Porra. Alterations in Pigment Content in Leaves of Pisum sativum After Exposure to Supplementary UV-B. Plant and Cell Physiology, 1992, Vol. 33, No. 7 1015-1023
  23. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/BF00027213, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/BF00027213 instead.
  24. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/BF00201050, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/BF00201050 instead.
  25. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 19453506, please use {{cite journal}} with |pmid=19453506 instead.
  26. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 15023701, please use {{cite journal}} with |pmid=15023701 instead.
  27. ^ http://www.newscientist.com/article/mg17523535.700-not-just-a-pretty-face.html
  28. ^ Bose, J.C., The Nervous Mechanisms of Plants, Longmans, Green and Co., London. 1926
  29. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1038/118654a0, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1038/118654a0 instead.
  30. ^ C Backster. Evidence of a primary perception in plant life. International Journal of Parapsychology, 1968
  31. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1126/science.189.4201.478, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1126/science.189.4201.478 instead.
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