地黄栽培种与野生种内源激素含量的差异

块根的发育和形成与植物内源激素密切相关。本研究测定地黄2个栽培种和2个野生种在生长发育过程中内源激素含量表明，地黄叶片中IAA、ZR和ABA含量变化均呈单峰曲线，即在拉线期及快速增长期逐渐升高，之后逐渐降低，但各生育期栽培种叶片中IAA、ZR和ABA含量均高于野生种；栽培种与野生种块根中IAA和ZR含量变化规律明显不同，在拉线期与快速增长期，栽培种迅速上升，而后逐渐降低，而在整个生长期野生种变化不明显；整个生育期参试品种叶片中GA含量变化不大，栽培种在快速增长期根中GA、ABA的含量迅速上升，而野生种变化不明显。从上述变化规律来看，地黄块根的形成与发育是多种内源激素协同作用的结果。IAA和ZR是块根起始分化关键激素，决定了块根的形成，GA、ABA在地黄块根的发育与膨大中起了更重要的作用。

Changes of Hormones in Cultivars and Wild-Type Varieties of Rehmannia glutinosa Libosch

The formation and development of tuberous roots is related to plant endogenous hormones. We determined the contents of IAA, ZR, GA and ABA in leaves and roots of two cultivars and two wild-type varieties of Rehmannia glutinosa during the growth periods and compared their developmental changing trends between cultivars and wild-type varieties of Rehmannia glutinosa. The results showed that the contents of IAA, ZR, and ABA in leaves of cultivated Rehmannia glutinosa were higher than those of wild-type varieties and their changes in both cultivated and wild type of R. glutinosa displayed the same single-peak curves during the growth periods, they were all increased gradually at the elongation and rapid enlargement stages of roots and then decreased gradually. There was no significant developmental change in GA content in the leaves of both cultivated and wild-type varieties. Hormone contents in roots of cultivars had quite different developmental changes from those of wild-type varieties: The contents of IAA, ZR, and ABA in the cultivars presented the changing trend of single-peak curves during root growth periods while GA content increased rapidly in root enlargement stage. There was no much developmental change in IAA and GA contents in roots of wild-type varieties. ZR content decreased gradually with the root development in wild-type varieties. ABA content changed in roots of wild-type varieties displayed a single-peak curve which was much lower than that of the cultivars. This different developmental changes of hormone contents in rehmannia roots between cultivars and wild-type varieties indicated that the development of the rehmannia tuberous roots is affected by synergitic effects of several hormones and that IAA and ZR act on the initiation of tuberous roots, whereas GA and ABA play a more important role in root enlargement and thickening.