Chemical Aspects of Some Bioregulators

Sauter, Holger

doi:10.1021/bk-1984-0257.ch002

Cited by 10 publications

(7 citation statements)

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“…l'WO point to this mode of action. Thus, the enzyme is inactivated (Coolbaugh et al 1978, Sauter 1984, Taton et al 1988). Sueh membrane-bound, microsomal enzymes catalyze many oxidative reactions in the most varied metabolic pathways.…”

Section: Chemical Structure and Mode Of Actionmentioning

confidence: 99%

Plant growth retardants as tools in physiological research

Großmann¹

1990

Physiol Plant

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Grossmann, K. 1990. Plant growth retardants as tools in physiological research. -Physiol. Plant. 78: 640-648.Besides being applied in agriculture and horticulture, the new types of plant growth retardants from norbornanodiazetine, triazole, pyrimidine, 4-pyridine and imidazole strueture are increasingly used in physiological researeh. As inhibitors of special eytochrome F-450 dependent monooxygenases they allow valuable insights in the regulation of terpenoid metabolism concerning phytohormones and sterols, thus showing relations to cell division, cell elongation and senescence.

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Section: Chemical Structure and Mode Of Actionmentioning

confidence: 99%

Plant growth retardants as tools in physiological research

Großmann¹

1990

Physiol Plant

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“…These oxidative demethylation steps are catalyzed by a Cyt P-450-dependent monooxygenase. It is assumed that the compounds interact with the protoheme iron of the Cyt P450, thus displacing oxygen from its binding site (3,26). However, the isoprenoid pathway brings forth other metabolites important for growth, too, which employ Cyt P450 enzyme activity in their synthesis.…”

Section: Resultsmentioning

confidence: 99%

Regulation of Plant Morphology by Growth Retardants

Großmann¹,

Kwiatkowski²,

Siebecker³

et al. 1987

Plant Physiol.

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The effects of the growth retardants tetcyclacis, a norbornenodiazetine, and LAB 150 978, a dioxanylalkenyl triazole, on seedling growth and endogenous levels of phytohormone-like substances in Glycine max L. cv Maple Arrow were studied. The levels of phytohormone-like substances in the root and in the various shoot tissues were analyzed by immussay. After seed treatment with both compounds, shoot growth was reduced more intensively than root growth. Both compounds decreased, on a fresh weight basis, the amount of various immunoreactive gibberellins when compared with the levels in control plants, especially in the shoot tip. Likewise, the growth retardants lowered the levels of abscisic acid-like material, particularly in the primary leaf, the epicotyl and the root. In contrast, the levels of trans-zeatin-riboside and dihydrozeatin-riboside-type cytokinins were considerably elevated by the growth retardants, mainly in the primary leaf, epicotyl, and hypocotyl. On the other hand the level of isopentenyladenosine-like material was less influenced. In general, the immunoreactive 3-indoleacetic acid content in the different plant parts was changed only slightly. It is assumed that besides their effect on gibberellin content both compounds interfere directly or indirectly with the regulation of the endogenous levels of abscisic acid and cytokinins. This might be seen as an additional mode of action of growth retardants explaining some side effects on developmental processes of treated plants, &g. delayed senescence and enhanced chlorophyll concentration in the leaves.The regulation of plant morphogenesis depends on environmental factors such as light, temperature and nutrient supply, the concentration and interaction of endogenous plant hormones, and upon the changing sensitivity of the tissue to these substances. In addition, many synthetic compounds are known which are able to modify the growth habit of plants when applied exogenously. Among them plant growth retardants influence cell division and cell enlargement in the subapical meristems of the shoot (20,24) probably by interfering with the gibberellin (GA') and sterol biosynthesis (4). Recently, it has been shown for new plant growth retardants of the triazole and norbornenodiazetine type that they inhibit GA biosynthesis in a cell-free system of pumpkin endosperm by blocking the oxidative reactions from ent-kaurene to ent-kaurenoic acid (8, 23). Data have been presented that these compounds reduce the GA content in intact plants, too (12, 32). However, results from cell suspension cultures provide evidence that the norbomenodiazetine tetcyclacis I Abbreviations: GA. = gibberellin A,; ABA = 2-cis-abscisic acid; DZR = dihydrozeatin riboside; IPA = isopentenyladenosine; mAB = monoclonal antibodies; ZR = trans-zeatin riboside. inhibits cell division growth by influencing the sterol biosynthesis (10). This effect is accompanied by alterations in protein biosynthesis and membrane permeability (9, 1 1), which might also be an explanation for reduced levels o...

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“…Macroscopic effects include growth retardation, stunted and compact growth, intense green coloring and, frequently, improved lodging resis-tance of the plants [26]. The spectrum of activity in different plant varieties depends mainly on the individual structure of the onium compound [27].…”

Section: Gibberellin Antagonistsmentioning

confidence: 99%

“…These agents all have a sp 2 -hybridized nitrogen atom which can complex the central iron atom in some cytochrome P450 enzymes. They block the oxidative steps of GA synthesis that lead to ent-kaurenoic acid [27].…”

Section: Gibberellin Antagonistsmentioning

confidence: 99%