ISSN:
1573-5087
Keywords:
Ethylene
;
ethephon
;
3,5-diiodo-4-hydroxybenzoic acid (DIHB)
;
roots
;
oxygen deficiency
;
oilseed rape (Brassica napus)
;
barley (Hordeum vulgare)
;
environmental stress
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The apical 2 cm of seedling roots of oilseed rape (Brassica napus L., cv. ‘Primor’) produced more ethylene than adjacent, older tissue. Treatment with ⩽ 5 × 10−3 mol m−3 3,5-diiodo4-hydroxybenzoic acid (DIHB), a presumed inhibitor of ethylene action, failed to stimulate root extension. Larger concentrations were inhibitory. Ethylene, applied as ethephon decreased root extension but DIHB (5 × 10−3 mol m−3) partially overcame this effect. Oxygen concentrations below that present in air also inhibited root extension but this was not ameliorated by DIHB. Roots of barley seedlings (Hordeum vulgare L., cv. ‘Midas’) evolved ethylene more slowly than roots of oilseed rape. DIHB (10−3−10−2 mol m−3) stimulated root extension in the absence of ethephon. Ethephon alone retarded root extension but DIHB partially overcame this inhibition. Small concentrations of oxygen also inhibited root extension but DIHB failed to ameliorate the effect even though the slow growth of oxygen-deficient roots (3–5% oxygen) was associated with abnormally fast rates of endogenous ethylene production. Extension growth in different oxygen concentrations was more closely associated with rates of oxygen consumption than with the amount of ethylene produced. Thus respiration rather than ethylene appeared to limit root extension under oxygen deficiency. This may explain why DIHB was unable to offset this form of environmental stress.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00124773
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