Studies on translocation of plant hormones in vascular tissue.

建立灵敏、可靠的高等植物维管组织中植物激素的分析方法具有重要意义。为此，通过化学或部分生物转化制备了几种氘标记的赤霉素，作为GC/SIM分析的内标。建立了将氚引入赤霉素的简便方法。利用激光昆虫法获得的水稻韧皮部液和褐飞虱分泌的蜜露，研究了植物激素在维管组织中的转运。用GC/SIM法在蜜露中鉴定出赤霉素A_1（GA_1）、GA_4、GA_<19>、GA_<20>和GA_<29>，并观察了它们在水稻不同生育期蜜露中的含量变化。GA_<19>是主要的赤霉素，其含量在最大分蘖期增加，在穗萌发-抽穗期下降。其他赤霉素水平较低，无显著变化。采用电子俘获检测器气液色谱法测定了蜜露中的ABA。ABA含量从第3叶开始逐渐增加，在最大分蘖期达到最大值，在穗萌发期下降。采用气液色谱法对激光昆虫法获得的韧皮部液中ABA进行了鉴定。然而，由于韧皮部汁液中赤霉素的含量很低，因此无法在韧皮部汁液中检测到赤霉素。为明确韧皮部汁液中植物激素与蜜露激素的关系，将蔗糖和赤霉素或ABA分别饲喂褐飞虱，并对其分泌的蜜露进行了分析。虽然样品溶液中的赤霉素与蜜露中的赤霉素没有太大的差异，但是关于这个问题还没有得到明确的结论。

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.