Either 5-[3H]indole-3-acetic acid (IAA) or 5-[3H]indole-3-acetyl-myo-inositol was applied to the endosperm of kernels of dark-grown Zea mays seedlings. The distribution of total radioactivity, radiolabeled indole-3-acetic acid, and radiolabeled ester conjugated indole-3-acetic acid, in the shoots was then determined. Differences were found in the distribution and chemical form of the radiolab...

Further studies with inhibitors of protein synthesis are presented to support the conclusion, drawn from work with chloramphenicol, that protein synthesis is a critical limiting factor in auxin-induced cell expansion. The indoleacetic acid-induced elongation of oat coleoptile sections was strongly inhibited by dl-p-fluorophenylalanine, and the inhibition is antagonized by phenylalanine. Puromyc...

In the previous paper (2) we reported that a substantial increase in gross cell wall synthesis occurs when oat coleoptile cylinders whose elongation is inhibited by Ca+ + are treated with IAA; this effect of auxin is direct in the sense that it is due to hormone action rather than to the occurrence of elongation. This paper presents information on the components of the cell wall whose synthesis...

Three bioassays were used for testing the level of regulator activity in methanolic extracts of the various fruit tissues: (a) the wheat coleoptile straight growth assay, to test auxins and coleoptile elongation-inhibiting substances; (b) the barley endosperm assay, to test gibberellin activity and the inhibitors of this activity; and (c) the growth of soybean callus in tissue culture, to test ...

An early auxin-induced gene was isolated from rice (Oryza sativa L. subsp. japonica cv Nihonmasari) coleoptiles by a fluorescent-labeled differential display screen. The full-length gene contains conserved domains characteristic for the cytochrome p450 superfamily. This gene, designated as CYP87A3, was weakly expressed in dark-grown coleoptiles but was up-regulated rapidly and transiently when ...

Zea mays L. cv INRA 5a coleoptile segments ecidify the incubation medium on the addition of 1-naphthyl acetate (1-NA). The buffering capacity of the bathing solution increases during 1-NA stimulated medium acidification. The solution bathing the 1-NA treated coleoptile segment was analyzed by high performance liquid chromatography. A considerable amount of acetic acid was detected in the bathin...

Introduction The effect of incandescent light on the electrical potentials of etiolated seedlings has been studied by only a few investigators. WALTm E(7) maintained that etiolated seedlings gave little, if any, electrical response when illuminated. CLARK (1), however, has demonstrated changes in the longitudinal electrical polarity in intact etiolated Avena seedlings when they are uniformly il...

The physiological activity of exogenous 4-Cl-IAA, as compared to IAA, was examined in maize coleoptile segments. It was found that in this model system 4-Cl-IAA is much more active in the stimulation of elongation than IAA. Simultaneous measurements of growth and external pH indicated that administration of either IAA or 4-Cl-IAA resulted in medium acidification. The kinetics of the pH changes,...

It is known that removal of the endosperm (deseeding) reduces subsequent auxin production in the oat coleoptile tip and the "regeneration of the physiological tip" (auxin production) in the decapitated coleoptile as determined by the quantities of auxin which are secreted into agar blocks and assayed by the Avena curvature test (10). This decrease in auxin production is associated with parallel...