University of California, Davis, California.
Plant Physiol. 1966 May;41(5):871-6. doi: 10.1104/pp.41.5.871.
An increase in starch content of cells in the abscission zone of the cotton explant appeared correlated with an increase in number of cells. A large increase in the number of cells in the abscission zone, concomitant with an increase in starch content, followed treatment with gibberellin as compared to auxin. In the final stages of abscission starch was hydrolyzed in the cells of the separation layer. Some starch remained after the petiole abscised.A positive phloroglucinol-hydrochloric acid reaction in the cells of the petiole distal to the line of separation indicated the presence, not of lignin, but of soluble sugars and uronic acids. This reaction was especially intense following gibberellic acid treatment.It was concluded that gibberellin in accelerating abscission leads to (1) an increase in cell number and starch content in the abscission zone, (2) the hydrolysis of starch in the separation layer just before abscission, and (3) the breakdown of polysaccharides and the release of soluble sugars and uronic acids. Auxin, an abscission retardant, either delays or prevents these events.
棉花外植体离区细胞的淀粉含量增加似乎与细胞数量的增加有关。与生长素相比，赤霉素处理后，离区细胞数量大量增加，同时淀粉含量增加。在离区的最后阶段，细胞内的淀粉被水解。叶柄脱落时，仍有一些淀粉残留。叶柄分离线远端细胞中对间苯三酚盐酸的阳性反应表明，存在的不是木质素，而是可溶性糖和糖醛酸。用赤霉素处理后，这种反应尤其强烈。结论是，赤霉素在加速脱落过程中导致：（1）离区细胞数量和淀粉含量增加；（2）离区前分离层中淀粉的水解；（3）多糖的分解以及可溶性糖和糖醛酸的释放。作为脱落抑制剂的生长素会延迟或阻止这些事件的发生。
