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Chlormequat structure.svg
IUPAC name
Other names
Chlorocholine; Chlorcholine
3D model (JSmol)
Molar mass 122.62 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Chlormequat is an organic compound with the formula ClCH
that is used as a plant growth regulator. It is typically sold as the chloride salt, chlormequat chloride, a colorless hygroscopic crystalline substance that is soluble in water and ethanol.[1] It is an alkylating agent and a quaternary ammonium salt.

Chlormequat has been called the "most important inhibitor of gibberellin biosynthesis."[1] As such, it inhibits cell elongation, resulting is thicker stalks, which are sturdier, facilitating harvesting of cereal crops.[2]

Regulation and toxicity[edit]

In the United States, chlormequat is classified as a low risk plant growth regulator and it is registered for use on ornamental plants grown in greenhouses, nurseries, and shadehouses.[3] It is not approved for use on crops intended for animal or human consumption.[3]

The LD50 (rat, oral) is low, approximately 670 mg/kg.[1]

Exposure to high levels of chlormequat has been linked to developmental toxicity in animal models.[4] It also affects reproduction in mammals.[5]

It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[6]


  1. ^ a b c Wilhelm Rademacher, Lutz Brahm "Plant Growth Regulators" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2010. doi:10.1002/14356007.a20_415.pub2
  2. ^ Gowariker, Vasant; Kalyani Paranjape; Sudha Gowariker; V. N. Krishnamurthy (2013). The pesticide encyclopedia. Wallingford: CABI. p. 93. ISBN 978-1780640143.
  3. ^ a b Chlormequat Chloride Reregistration Eligibility Decision for Low Risk Pesticide
  4. ^ "Chlormequat". Food and Agricultural Organization of the United Nations.
  5. ^ Sørensen, MT; Danielsen, V (February 2006). "Effects of the plant growth regulator, chlormequat, on mammalian fertility". International Journal of Andrology. 29 (1): 129–33. doi:10.1111/j.1365-2605.2005.00629.x. PMID 16466532.
  6. ^ "40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities" (PDF) (July 1, 2008 ed.). Government Printing Office. Retrieved October 29, 2011.