Plant growth retardants

W. Rademacher, "Biochemical Effects of Plant Growth Retardants," in Plant Biochemical Regulators, Marcel Dekker Inc, New York, 1991. 

Nitrogen fertilizers ensure plant growth. Retarding formulations prevent excessive washing away of the fertilizer from the soil. 

Isophorone is a solvent for a large number of natural and synthetic polymers, resins, waxes, fats, and oils. Specifically, it is used as a solvent for concentrated vinyl chloride/acetate-based coating systems for metal cans, other metal paints, nitrocellulose finishes, printing inks for plastics, some herbicide and pesticide formulations, and adhesives for plastics, poly(vinyl) chloride and polystyrene materials (Papa and Sherman 1981). Isophorone also is an intermediate in the synthesis of 3, 5-xylenol, 3, 3, 5-trimethylcyclohexanol (Papa and Sherman 1981), and plant growth retardants (Haruta et al. 1974). Of the total production, 45-65% is used in vinyl coatings and inks, 15-25% in agricultural formulations, 15-30% in miscellaneous uses and exports, and 10% as a chemical intermediate (CMA 1981). 

Haruta H, Yagi H, Iwata T, Tamura S. 1974. Syntheses and plant growth retardant activities of quaternary ammonium compounds derived from a-ionone and isophorone. Agric Biol Chem 38 417-422. 

Hedden, P., Phinney, B.O., MacMillan, J., Sponsel, V.M. "Metabolism of kaurenoids by Gibberella fujlkurol in the presence of the plant growth retardant, N,N,N-trimethyl-l-methyl-(2, 6, 6 -trimethylcyclohex-2 -en-1 -yl)prop-2-enylammonium iodide." Phytochemistry, 1977, 16, 1913-1917. 

The metabolism of ent-kaur-16-ene by Gibberella fujikuroi in the presence of the plant-growth retardant (78) follows the normal pattern. However, kaur-16-ene, phyllocladene (13/3-kaur-16-ene), with the steroid-like a/b fusion, and ent-kaur-15-ene were not metabolized. The transformation by Gibberella fujikuroi of 2- and 3-hydroxylated kaurenoids to a range of hydroxylated... 

The use of monophosphazenes of the type Bu3P=N CeH4X (X = 0-NO2, m-F, /n-CFg, or 0-CF3), prepared by the azide route, for plant growth retardation has been proposed in a patent application. ... 

K. Komal, Y. Suglwaka and S. Sato, "Plant-growth Retardant of Extracts Obtained from Water Nutgrass (Cyperus serotinus Rottb.)", Klnkl Dalgaku Nogakubu Klyo, 1981, (14), 57-65. 

Uses Plant growth retardant for container-grown ornamentals... 

Plant hormone biosynthesis and metabolism are influenced and modified, too, as already mentioned, by a large number of typical secondary plant constituents of quite different structures (Eef. 5, 6). For instance, it has been shown that some oi-disubstituted acetic acid derivatives are active both as antiauxins and as inhibitors of the biosynthesis of cyclic terpenoids. Thus, some more simple model compounds synthesized by ourselves, for example substituted a-phenoxy-isobutyrio acids, are not only competitive auxin inhibitors but they are also able to inhibit both the gibberellin and sterol biosynthesis. The same is true for some well known plant growth retardants, such as CCO or AMO 1618, which are inhibitors of gibberellin biosynthesis both in plants and in Fus ium moniliforme, but at the same time they are inhibiting and modifying also the biosynthesis of steroids in the respective organisms as well as in animal in vitro systems (Eef. 29) ... 

Lang, The plant growth retardant CCC as inhibitor of gibberellin biosynthesis in Fusarium moniliforme, PIanta 61, 229 (1964). 

A complementary approach is the use of chemical inhibitors of GA-biosynthesis. Surprisingly this method using synthetic plant growth retardants has only recently been used (20, 21, 23) to study GA-biosynthesis in the absence of the normal fungal metabolites. 

Phosphon D 2,4-dichlorobenzyltri-n-butylphos-phonium chloride, a synthetic plant growth retardant e.g. it inhibits the growth of chrysanthemiun stems and induces flowering. 

The Action of Plant Growth Retardants at the Biochemical Level... 

Recent research indicates that certain plant growth retardants improve the chilling resistance of plants [24]. Application of paclobutrazol to cucumber, squash [33] and rice [25, 34] will increase chilling resistance. Triadimefon has the same effect on bean [1], cabbage, barley [9] and cucumber [35]. There are three views concerning the relationship between plant growth retardants and endogenous ABA ... 

Some plant growth retardants can inhibit ABA biosynthesis in the fungus Cerco-spora rosicola [22]. The most effective were paclobutrazol, ancymidol and decylimidazole [21]. CCC, Alar and paclobutrazol also act as inhibitors of GA biosynthesis and both ABA and GA are synthesized via the isoprenoid pathway. However, different growth inhibitors act at different points on the pathway and thus may inhibit either or both ABA and GA biosynthesis. 

CCC, Phosphon D and AMO-1618 did not affect the biosynthesis of mevalonic acid in the avocado mesocarp [20]. Alar inhibited GA synthesis but did not affect ABA synthesis [22]. The difference in results obtained may be due to the concentration of plant growth retardant applied. 

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