Editing Plant hormone (section)

{{Short description|Chemical compounds that regulate plant growth and development}}
[[File:Auxin.jpg|thumb|Lack of the plant hormone [[auxin]] can cause abnormal growth (right)|150px|right]]

'''Plant hormones''' (or '''phytohormones''') are [[signal molecule]]s, produced within [[plant]]s, that occur in extremely low [[concentration]]s. Plant hormones control all aspects of plant growth and development, including [[embryogenesis]],<ref>{{cite journal | vauthors = Méndez-Hernández HA, Ledezma-Rodríguez M, Avilez-Montalvo RN, Juárez-Gómez YL, Skeete A, Avilez-Montalvo J, De-la-Peña C, Loyola-Vargas VM | display-authors = 6 | title = Signaling Overview of Plant Somatic Embryogenesis | journal = Frontiers in Plant Science | volume = 10 | pages = 77 | date = 2019 | pmid = 30792725 | pmc = 6375091 | doi = 10.3389/fpls.2019.00077 | doi-access = free }}</ref> the regulation of [[Organ (anatomy)|organ]] size, [[pathogen]] defense,<ref>{{cite journal | vauthors = Shigenaga AM, Argueso CT | title = No hormone to rule them all: Interactions of plant hormones during the responses of plants to pathogens | journal = Seminars in Cell & Developmental Biology | volume = 56 | pages = 174–189 | date = August 2016 | pmid = 27312082 | doi = 10.1016/j.semcdb.2016.06.005 }}</ref><ref>{{cite journal | vauthors = Bürger M, Chory J | title = Stressed Out About Hormones: How Plants Orchestrate Immunity | journal = Cell Host & Microbe | volume = 26 | issue = 2 | pages = 163–172 | date = August 2019 | pmid = 31415749 | doi = 10.1016/j.chom.2019.07.006 | pmc = 7228804 }}</ref> [[Stress (biology)|stress]] tolerance<ref>{{cite journal | vauthors = Ku YS, Sintaha M, Cheung MY, Lam HM | title = Plant Hormone Signaling Crosstalks between Biotic and Abiotic Stress Responses | journal = International Journal of Molecular Sciences | volume = 19 | issue = 10 | pages = 3206 | date = October 2018 | pmid = 30336563 | pmc = 6214094 | doi = 10.3390/ijms19103206 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Ullah A, Manghwar H, Shaban M, Khan AH, Akbar A, Ali U, Ali E, Fahad S | display-authors = 6 | title = Phytohormones enhanced drought tolerance in plants: a coping strategy | journal = Environmental Science and Pollution Research International | volume = 25 | issue = 33 | pages = 33103–33118 | date = November 2018 | pmid = 30284160 | doi = 10.1007/s11356-018-3364-5 | bibcode = 2018ESPR...2533103U | s2cid = 52913388 }}</ref> and [[Reproduction|reproductive]] development.<ref>{{cite journal | vauthors = Pierre-Jerome E, Drapek C, Benfey PN | title = Regulation of Division and Differentiation of Plant Stem Cells | journal = Annual Review of Cell and Developmental Biology | volume = 34 | pages = 289–310 | date = October 2018 | pmid = 30134119 | pmc = 6556207 | doi = 10.1146/annurev-cellbio-100617-062459 }}</ref> Unlike in [[animal]]s (in which hormone production is restricted to specialized [[gland]]s) each plant cell is capable of producing hormones.<ref>{{cite web | title = Plant hormones | url = https://biology.tutorvista.com/biomolecules/plant-hormones.html | publisher = NCS Pearson | access-date = 2018-08-14 | archive-date = 2021-11-27 | archive-url = https://web.archive.org/web/20211127163827/https://biology.tutorvista.com/biomolecules/plant-hormones.html | url-status = dead }}</ref><ref>{{cite web | url= http://www.scienceindia.in/home/view_article/70 | title= Plant Hormones | access-date= 2018-08-14 | archive-date= 2019-12-18 | archive-url= https://web.archive.org/web/20191218172837/http://www.scienceindia.in/home/view_article/70 | url-status= dead }}</ref> [[Frits Warmolt Went|Went]] and [[Thimann]] coined the term "phytohormone" and used it in the title of their 1937 book.<ref name="WentThimann">{{cite book | vauthors = Went FW, Thimann KV |date= 1937 |title= Phytohormones | url = https://archive.org/details/in.ernet.dli.2015.351314 |publisher= The Macmillan Company |location= New York }}</ref>

Phytohormones occur across the [[plant kingdom]], and even in [[algae]], where they have similar functions to those seen in [[vascular plant|vascular plants ("higher plants")]].<ref>{{cite journal | vauthors = Tarakhovskaya ER, Maslov Y, Shishova MF | year = 2007 | title = Phytohormones in algae | journal = Russian Journal of Plant Physiology | volume = 54 | issue = 2| pages = 163–170 | doi= 10.1134/s1021443707020021| s2cid = 27373543 }}</ref> Some phytohormones also occur in [[microorganism]]s, such as unicellular [[fungus|fungi]] and [[bacteria]], however in these cases they do not play a hormonal role and can better be regarded as [[secondary metabolites]].<ref>
{{cite journal | doi= 10.1007/BF00029903 | volume= 15 | issue= 3 | title= Gibberellin formation in microorganisms | journal= Plant Growth Regulation | pages= 303–314| year= 1994 | vauthors = Rademacher W | s2cid= 33138732 }}
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