A gibberellin

Abscisin II is a plant hormone which accelerates (in interaction with other factors) the abscission of young fruit of cotton. It can accelerate leaf senescence and abscission, inhibit flowering, and induce dormancy. It has no activity as an auxin or a gibberellin but counteracts the action of these hormones. Abscisin II was isolated from the acid fraction of an acetone extract by chromatographic procedures guided by an abscission bioassay. Its structure was determined from elemental analysis, mass spectrum, and infrared, ultraviolet, and nuclear magnetic resonance spectra. Comparisons of these with relevant spectra of isophorone and sorbic acid derivatives confirmed that abscisin II is 3-methyl-5-(1-hydroxy-4-oxo-2, 6, 6-trimethyl-2-cyclohexen-l-yl)-c s, trans-2, 4-pen-tadienoic acid. This carbon skeleton is shown to be unique among the known sesquiterpenes. 

West, C.A., Phinney, B.O. "Gibberellins from flowering plants. I. Isolation and properties of a gibberellin from Phaseolus vulgaris L." J.A.C.S., 1959, 81, 2k2h-2k27. 

Kinsman, L. T., Pinfield, N. J., and Stobart, A. K. 1975. A gibberellin bioassay based on betacyanin production in Amaranthus caudatus seedlings. Planta 127, 149-152... 

Lange, T., Hedden, P. and Graebe, J.E. (1994) Expression cloning of a gibberellin 20-oxidase, a multifunctional enzyme involved in gibberellin biosynthesis. Proc. Natl. Acad. Set. USA, 91, 8552-6. 

Recently, a gibberellin receptor has been identified. The gibberellins mediate several plant developmental processes. They are associated with activities ranging from the induction of a-amylase in the germination of seeds, to stem elongation to the development of flowers and fruit. 

The facile conversion of the 6,8-dioxabicyclo[3.2.1]octanes to chiral pyrans is exploited in steps towards the synthesis of ( —)-(6 S, l iS)-pestalotin (478), a gibberellin synergist isolated from microorganisms. Treatment of either tosylate 471 or mesylate 476 with lithium di- -... 

The antheridium-inducing factor of the fern Anemia phyllitidis has been shown to have a gibberellin-like structure (101), reminiscent of the rearrangement products of gibberellic acid in concentrated sulphuric acid. ... 

Gibberellins stimulate cell division and elongation, break seed dormancy, and speed up germination. If the seeds of some species are difficult to germinate you can soak them in a gibberellin solution to get them started. 

EL-531, a-cyelopmpyl-a-(4-methoxypkettyl)-5-pyrimidtne methanol a synthetic growth retardant. It is a gibberellin antagonist which delays the growth of lettuce hypocotyls. 

Heliangin a sesquilactone and plant growth inhibitor first isolated from the leaves of the Jerusalem artichoke (Helianthus tuberosus). It is a gibberellin antagonist and inhibits the growth of oat coleoptiles but it stimulates root growth in beans (Phaseolus spp.). 

Succinic acid 2,2-dimethylhydrazine, dimetha-zUe, B-99S HOOC-(CH2)2 0-NH-N(CH3)2. a synthetic growth regulator. It acts as a gibberellin antagonist and growth retardant, and is especially active in dicotyledonous plants. It increases the number of blossoms on fruit trees and prevents loss of immature huit. 

Ho THD, Shih S, Kleinhofs A (1980) Screening for barley mutants with altered hormone sensitivity in their aleurone layers. Plant Physiol 66 153-157 Ho THD, Nolan RC, Shute DE (1981) Characterization of a gibberellin-insensitive dwarf wheat, D 6899 Evidence for a regulatory step common to many diverse responses to gibberellins. Plant Physiol 67 1026-1031... 

Naylor JM, Simpson GM (1961) Dormancy studies in seed of Avena fatua. 2. A gibberellin sensitive inhibitory mechanism in the embryo. Can J Bot 39 281-295 Nickell LG (1982) Plant growth regulators. Agricultural uses. Springer, Berlin Heidelberg New York... 

Thomas TH, Wareing PF, Robinson PM (1965) Chemistry and physiology of dormins in sycamore. Action of the sycamore dormin as a gibberellin antagonist. Nature 205 1270-1272... 

Loreti, E., Bellincampi, D., Millet, C., Alpi, A., and Perata, P. (2002). Elicitors of defence responses repress a gibberellin signalling pathway in barley embryos. /. Plant Physiol 159, 1383-1386. 

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