Journal article
Effect of Calmodulin Antagonists on Auxin-Induced Elongation 1
Plant physiology (Bethesda), Vol.79(1), pp.28-33
09/1985
Handle:
https://hdl.handle.net/2376/114572
PMCID: PMC1074824
PMID: 16664387
Abstract
Coleoptile segments of oat (
Avena sativa
var Cayuse) and corn (
Zea mays
L. var Patriot) were incubated in different concentrations of calmodulin antagonists in the presence and absence of α-naphthaleneacetic acid. The calmodulin antgonists (chlorpromazine (CP), trifluoperazine, and fluphenazine) inhibited the auxin-induced elongation at 5 to 50 micromolar concentrations. Chlorpromazine sulfoxide, an analog of chlorpromazine, did not have significant effect on the elongation of oat and corn coleoptiles. A specific inhibitor of calmodulin
N
-(6-aminohexyl)5-chloro-1-naphthalenesulfonamide hydrochloride (W-7, a naphthalenesulfonamide derivative) inhibited coleoptile elongation, while its inactive analog
N
-(6-aminohexyl)-1-naphthalenesulfonamide hydrochloride (W-5) was ineffective at similar concentrations. During a 4-hour incubation period, coleoptile segments accumulated significant quantities of
3
H-CP. About 85 to 90% of auxin-induced growth was recovered after 4 hours of preincubation with CP or 12 hours with W-7 and transferring coleoptiles to buffer containing NAA. Leakage of amino acids from coleoptiles increased with increasing concentration of CP, showing a rapid and significant increase above 20 micromolar CP. The amount of amino acids released in the presence of W-7 and W-5 was significantly lower than the amount released in the presence of CP. Both W-5 and W-7 increased amino acid release but only W-7 inhibited auxin-induced growth. Calmodulin activity measured by phosphodiesterase activation did not differ significantly between auxin-treated and control coleoptile segments. These results suggest the possible involvement of calmodulin in auxin-induced coleoptile elongation.
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Details
- Title
- Effect of Calmodulin Antagonists on Auxin-Induced Elongation 1
- Creators
- K. G Raghothama - Department of Horticulture and Landscape Architecture, Washington State University, Pullman, Washington 99164-6414Yosef Mizrahi - Department of Horticulture and Landscape Architecture, Washington State University, Pullman, Washington 99164-6414B. W Poovaiah - Department of Horticulture and Landscape Architecture, Washington State University, Pullman, Washington 99164-6414
- Publication Details
- Plant physiology (Bethesda), Vol.79(1), pp.28-33
- Academic Unit
- Horticulture, Department of
- Identifiers
- 99900548343301842
- Language
- English
- Resource Type
- Journal article