The senescence of excised discs of primary leaves of Phaseolus vulgaris, L., var. Red Kidney was followed by measuring the net breakdown of protein and chlorophyll. The chemical growth regulators indoleacetic acid, 2,4-dichlorophenoxy-acetic acid, gibberellic acid, kinetin, and 6-benzylaminopurine were relatively ineffective in retarding senescence in this tissue. White light, on the other hand...

A previously described [OLIN. CHEM. 18, 778(1972)] ch romatogra phic sepa ration and fluorometric system has been adapted to determination of 5hyd roxyindole-3-acetic acid and indole-3-acetic acid in body fluids and biological extracts. A strong anion-exchange resin, “Aminex A-27,” is used. The indoleacetic acids are eluted at 60#{176}C with a single ammonium acetate-acetic acid buffer. No grad...

Increased auxin levels in root primordia are important controlling branching, while their interaction with abscisic acid (ABA) likely regulates lateral development water-deficient plants. The role of ABA accumulation regulating branching was investigated using immunolocalization to detect (indoleacetic acid, IAA) and (abscisic acid) the ABA-deficient barley mutant Az34 its parental genotype (cv...

We examined the sensitivity and the specificity of three versions of the Salkowski colorimetric technique. Two of these allowed the detection of indoleacetic acid (IAA) over a low range of concentrations (0.5 to 20 (mu)g/ml), while the third permitted the detection of IAA over a range of higher concentrations (5 to 200 (mu)g/ml). Overall, the three formulations reacted not only with auxin (IAA)...

Chance (1) has proposed that the peroxidase-catalyzed oxidation of diiydroxyfumaric acid proceeds in two steps. The first step is the oxidation of the hydrogen donor by oxygen, the reaction being catalyzed by a manganese-activated peroxidase and accompanied by the production of hydrogen peroxide. The second step is the oxidation of additional hydrogen donor by hydrogen peroxide, this reaction a...