Editing Plant hormone (section)

===Other known hormones===
Other identified plant growth regulators include:
* [[Plant peptide hormones]] – encompasses all small secreted peptides that are involved in cell-to-cell signaling.  These small peptide hormones play crucial roles in plant growth and development, including defense mechanisms, the control of cell division and expansion, and pollen self-incompatibility.<ref>{{cite journal | vauthors = Lindsey K, Casson S, Chilley P | title = Peptides: new signalling molecules in plants | journal = Trends in Plant Science | volume = 7 | issue = 2 | pages = 78–83 | date = February 2002 | pmid = 11832279 | doi = 10.1016/S0960-9822(01)00435-3 | s2cid = 5064533 | doi-access = free }}</ref> The small [[peptide]] CLE25 is known to act as a long-distance signal to communicate water stress sensed in the roots to the stomata in the leaves.<ref>{{cite journal | vauthors = Takahashi F, Suzuki T, Osakabe Y, Betsuyaku S, Kondo Y, Dohmae N, Fukuda H, Yamaguchi-Shinozaki K, Shinozaki K | display-authors = 6 | title = A small peptide modulates stomatal control via abscisic acid in long-distance signalling | journal = Nature | volume = 556 | issue = 7700 | pages = 235–238 | date = April 2018 | pmid = 29618812 | doi = 10.1038/s41586-018-0009-2 | bibcode = 2018Natur.556..235T | s2cid = 4598494 }}</ref>
* [[Polyamine]]s – are strongly basic molecules with low molecular weight that have been found in all organisms studied thus far. They are essential for plant growth and development and affect the process of mitosis and meiosis. In plants, polyamines have been linked to the control of [[Plant senescence|senescence]]<ref>{{cite journal | vauthors = Pandey S, Ranade SA, Nagar PK, Kumar N | title = Role of polyamines and ethylene as modulators of plant senescence | journal = Journal of Biosciences | volume = 25 | issue = 3 | pages = 291–9 | date = September 2000 | pmid = 11022232 | doi = 10.1007/BF02703938 | s2cid = 21925829 }}</ref> and [[programmed cell death]].<ref>{{cite journal | vauthors = Moschou PN, Roubelakis-Angelakis KA | title = Polyamines and programmed cell death | journal = Journal of Experimental Botany | volume = 65 | issue = 5 | pages = 1285–96 | date = March 2014 | pmid = 24218329 | doi = 10.1093/jxb/ert373 | doi-access = free }}</ref>
* [[Nitric oxide]] (NO) – serves as signal in hormonal and defense responses (e.g. stomatal closure, root development, germination, nitrogen fixation, cell death, stress response).<ref name="Shapiro_2005">{{cite book | vauthors = Shapiro AD | chapter = Nitric oxide signaling in plants | volume = 72 | pages = 339–98 | date = 2005 | pmid = 16492476 | doi = 10.1016/S0083-6729(05)72010-0 | series = Vitamins & Hormones | isbn = 9780127098722 | title = Plant Hormones | s2cid = 13308295 }}</ref> NO can be produced by a yet undefined NO synthase, a special type of nitrite reductase, nitrate reductase, mitochondrial cytochrome c oxidase or non enzymatic processes and regulate plant cell organelle functions (e.g. ATP synthesis in chloroplasts and mitochondria).<ref>{{cite book | vauthors = Roszer T | year = 2012 | chapter = Nitric Oxide Synthesis in the Chloroplast | veditors = Roszer T | title = The Biology of Subcellular Nitric Oxide. | publisher = Springer | location = New York, London, Heidelberg | isbn = 978-94-007-2818-9 }}</ref>
* [[Karrikin]]s – are not plant hormones as they are not produced by plants themselves but are rather found in the smoke of burning plant material.  Karrikins can promote seed germination in many species.<ref>{{cite journal | vauthors = Chiwocha SD, Dixon KW, Flematti GR, Ghisalberti EL, Merritt DJ, Nelson DC, Riseborough JA, Smith SM, Stevens JC | display-authors = 6 |title = Karrikins: A new family of plant growth regulators in smoke |journal = Plant Science|date = 2009-10-01|pages = 252–256|volume = 177|issue = 4|doi = 10.1016/j.plantsci.2009.06.007 }}</ref> The finding that plants which lack the receptor of karrikin receptor show several developmental [[phenotype]]s (enhanced biomass accumulation and increased sensitivity to drought) have led some to speculate on the existence of an as yet unidentified karrikin-like endogenous hormone in plants. The cellular karrikin signalling pathway shares many components with the strigolactone signalling pathway.<ref>{{cite journal | vauthors = Li W, Nguyen KH, Chu HD, Ha CV, Watanabe Y, Osakabe Y, Leyva-González MA, Sato M, Toyooka K, Voges L, Tanaka M, Mostofa MG, Seki M, Seo M, Yamaguchi S, Nelson DC, Tian C, Herrera-Estrella L, Tran LP | display-authors = 6 | title = The karrikin receptor KAI2 promotes drought resistance in Arabidopsis thaliana | journal = PLOS Genetics | volume = 13 | issue = 11 | pages = e1007076 | date = November 2017 | pmid = 29131815 | pmc = 5703579 | doi = 10.1371/journal.pgen.1007076 | doi-access = free }}</ref>
* [[Triacontanol]] – a fatty alcohol that acts as a growth stimulant, especially initiating new basal breaks in the [[Rosaceae|rose family]]. It is found in [[alfalfa]] (lucerne), bee's wax, and some waxy leaf cuticles.