Studies on translocation of plant hormones in vascular tissue.

建立灵敏可靠的植物激素分析方法对高等植物维管组织中激素的研究具有重要意义。为此，通过化学或部分生物转化的方法制备了几种用于GC/SIM分析的内标物--氚标记的赤霉素。还建立了将氚引入赤霉素的简单方法。以激光-昆虫法获得的水稻韧皮部汁液和褐飞虱分泌的蜜露为材料，研究了植物激素在维管组织中的转运。用GC/SIM法对蜜露中的赤霉素A_1(GA_1)、赤霉素4(GA_4)、赤霉素19&gt；、赤霉素20&gt；和赤霉素29&gt；进行了鉴定，并观察了它们在水稻不同生育期的含量变化。GA_(19)&gt；是主要的赤霉素类物质，其含量在分蘖盛期升高，在穗分化抽穗期下降。其他赤霉素含量较低，含量变化不大。采用气-液色谱电子捕获检测器测定蜜露中的脱落酸(ABA)。ABA水平从三叶期开始升高，最大分蘖期达到最大值，成穗期下降。采用气-液色谱对激光-昆虫法提取的韧皮部汁液中的脱落酸进行了鉴定。Hawever，由于赤霉素含量很低，在韧皮部汁液中没有检测到赤霉素。为了弄清韧皮部汁液中植物激素与蜜露中激素的关系，用含有蔗糖和赤霉素或ABA的溶液饲喂褐飞虱，并对其分泌的蜜露进行分析。尽管样品溶液中的赤霉素与蜜露中的赤霉素相差不大，但这一问题尚未得出明确的结论。

It is important to establish very sensitive and reliable analysis methods for the investigation of plant hormones in vascular tissue of higher plants. For this purpose, several deuterium-labeled gibberellins, which are used as internal standards of GC/SIM analysis, were prepared by chemical or partly biological conversion. The simple method to introduce tritium into gibberellins was also establised. The translocation of plant hormones through vascular tissue was investigated by using phloem sap of rice obtained by laser-insect method as well as using honeydew excreted by brown planthopper. Gibberellin A_1(GA_1), GA_4, GA_<19>, GA_<20>, and GA_<29> were identified in honeydew by GC/SIM and the changes of their levels in honeydew at several growth stages of rice were observed. GA_<19> was the major gibberellin and its level increased at the stage of maximum tillering stage and then decreased at panicle initiation-heading stages. The levels of other gibberellins were low and there was no significant change of level.Abscisic scid(ABA) in honeydew was determined by gas-liquid chromatography using a electron capture detector. The level of ABA increased from 3rd leaf leaf stage, reached the maximum at maximum tillering stage and decreased at panicle initiation stage. ABA was identified by gas-liquid chromatography in the phloem sap obtained by laser-insect method. Hawever, gibberellins could not be identified in phloem sap due to their very low levels. To clarify the relationship between plant hormones in phloem sap and those in honeydew, the solution containing sucrose and gibberellins or ABA was fed to brown planthopper, and excreted honeydew was analyzed. Although there was not so large difference between gibberellins in sample solution and honeydew, clear conclusion on this problem has not been obtained.