Beschreibung:
<jats:p>The kinetics of auxin‐induced elongation of segments from <jats:italic>Vigna radiata</jats:italic> (L.) Wilczek hypocotyls have been investigated using auxanometer measurements. Doseresponse curves were established for several well‐defined parameters of the growth response. The experimental data revealed that different kinetic parameters were affected differently by increasing auxin concentrations. The dose‐response curves are slightly sigmoid for fresh weight, nearly bell‐shaped for total elongation or maximal elongation rate, and nearly linear for maximal growth acceleration. The effects of auxin concentration on regulation of growth orientation are discussed.</jats:p><jats:p>A biphasic response is observed mainly with segments taken from the middle of the hypocotyl (‘C’) which exhibit maximal growth rates. Segments from other levels, with lesser growth potentials, exhibit a very weak response. The two successive phases may then require different maturation states. Kinetics of the acceleration curves are very similar all along the hypocotyl and remain very homogeneous with increasing IAA concentrations.</jats:p>