MSU/AEC Plant Research Laboratory, Michigan State University, East Lansing.
Planta. 1969 Jun;86(2):124-33. doi: 10.1007/BF00379820.
Acidic extracts of the long-short-day plant Bryophyllum daigremontianum contain two gibberellin (GA)-like substances called fractions I and II. In plants under permanent short-day (SD) conditions the levels of both I and II are very low. In continuous long days (LD) the total GA content is approximately 20 times higher than in SD, mainly due to an increased level of II. Extracts of plants induced to flower by the shift LD→SD show a further increase in the level of II. Application of GA3 to plants in SD causes normal flower formation, but the level of fraction II remains as low as in vegetative plants in permanent SD.Approximately 10% of the GA3 applied could still be recovered from leaves and inflorescences after 45 days, indicating that GA3 is very stable in Bryophyllum, Most of the GA3 recovered was still associated with the treated leaves, but small amounts could be detected in other leaves and in inflorescences. Results of grafting experiments indicate that these low levels of GA3 are adequate to induce production of the floral stimulus.
长日照-短日照植物落地生根的酸性提取物含有两种赤霉素（GA）样物质，分别称为馏分 I 和 II。在长期处于短日照（SD）条件下的植物中，I 和 II 的水平都非常低。在连续的长日照（LD）下，总 GA 含量比 SD 高约 20 倍，主要是由于 II 水平的增加。由 LD→SD 转变诱导开花的植物提取物中 II 水平进一步增加。将 GA3 应用于 SD 中的植物会导致正常的花形成，但馏分 II 的水平仍然与永久性 SD 中的营养植物一样低。45 天后，仍可从叶片和花序中回收约 10%的 GA3，表明 GA3 在落地生根中非常稳定。回收的大部分 GA3 仍与处理过的叶片相关联，但在其他叶片和花序中也可以检测到少量 GA3。嫁接实验的结果表明，这些低水平的 GA3 足以诱导产生花刺激物。
