花叶千年木单个生殖器官和营养器官的体外直接再生的控制——单个器官直接再生的规律性

花叶千年木(Dracaena fragrans cv.massangeana Hort．)的各种单个器官(花被片、花芽、花序分枝、花序、成年态营养芽和幼态营养芽)在离体培养中被愈伤组织直接再生了。在这些单个器官的再生期间，一些规律性现象被观察到了。首先，单个再生器官种类的范围与分离外植体的器官在植物个体发育中被分化的时期有密切关系。从植株个体发育某个时期(时期A)分化的地上部分器官上分离的外植体能够分别再生下面这些地上部分器官：稍晚于时期A分化的器官，与时期A同期分化的器官和早于时期A分化的所有器官。其次，在这个范围内，究竟再生哪一种器官被再生取决于培养基中外源生长素的浓度。随着2，4-D浓度从0．005mg／L逐渐升高到0．5mg／L，单个再生器官的种类将按如下的次序变化：营养芽，花序，花序分枝，花芽，花被片。这些规律性现象将被用于诱导一个给定的被子植物地上部分器官的直接再生。

Control of In Vitro Regeneration of Individual Reproductive and Vegetative Organs in Dracaena fragrans cv. massangeana Hort. Regularities of the Direct Regenerationof Individual Organs In Vitro

Various individual organs (tepal, flower bud, inflorescence branch, inflorescence, adultvegetative bud and juvenile vegetative bud) were directly regenerated respectively by callus in Dracaenafragrans cv. massangeana Hort. During the regeneration of these individual organs some regularityphenomena were observed. Firstly, the kind range of the individual organs, which are directly regeneratedin vitro, is in close relationship to the differentiated stages of the organs used for explant excision duringplant ontogeny. The explants excised from the epigeous organ that is differentiated at some stage (stageA) during plant ontogeny must be able to separately regenerate all of those individual epigeous organs:ones differentiated slightly later than the stage A, ones differentiated at the stage A and all onesdifferentiated earlier than the stage A. Secondly, within this range which kind of organ is regenerateddepends on the exogenous auxin concentrations in medium. With the gradual increase of 2,4-Dconcentration from 0.005 mg/L to 0.5 mg/L, the kinds of regenerated organs will change by the order asfollows: vegetative bud, inflorescence, inflorescence branch, flower bud, tepal. These regularities will beable to be used for inducing the direct regeneration of a given epigeous organ in angiosperms.