Martin H V, Elliott M C
School of Life Sciences, Leicester Polytechnic, Leicester, LE1, 9BH, United Kingdom.
Plant Physiol. 1984 Apr;74(4):971-4. doi: 10.1104/pp.74.4.971.
The quantities of endogenous indol-3yl-acetic acid (IAA) in endosperms and scutella of 6-day-old maize seedlings (Zea mays L. cv Giant White Horsetooth) were determined by a fluorimetric method. Endosperms were found to contain 33.4 nanograms IAA per plant, and scutella 7.5 nanograms IAA per plant. [5-(3)H]IAA applied to endosperms of 6-day-old seedlings moved into the roots and radioactivity accumulated at the apex of the primary root within 8 hours. Two to 7-day-old seedlings were treated simultaneously with [5-(3)H]IAA in the endosperm and [2-(14)C] IAA on the shoot apex. The patterns of transport into the root were found to change during ontogeny: in successively older plants, transport from the shoot into the roots increased relative to transport from the endosperm into the roots. The auxin required for the growth of maize roots could, therefore, partially be contributed by the shoot and endosperm. Ontogenetic changes in the relative importance of these two supplies could be of significance for the integration of growth and development between shoot and root.
采用荧光法测定了6日龄玉米幼苗（Zea mays L. cv Giant White Horsetooth）胚乳和盾片中内源吲哚-3-乙酸（IAA）的含量。结果发现，胚乳中每株含有33.4纳克IAA，盾片中每株含有7.5纳克IAA。将[5-(3)H]IAA施用于6日龄幼苗的胚乳，8小时内IAA转移到根中，放射性在初生根顶端积累。对2至7日龄的幼苗，在胚乳中同时施用[5-(3)H]IAA，在茎尖施用[2-(14)C]IAA。结果发现，在个体发育过程中，IAA向根中的运输模式发生了变化：在逐渐长大的植株中，相对于从胚乳向根中的运输，从茎向根中的运输增加。因此，玉米根生长所需的生长素部分可由茎和胚乳提供。这两种生长素供应相对重要性的个体发育变化可能对茎和根之间生长与发育的整合具有重要意义。
