冬小麦分蘖衰亡过程中内源激素作用的研究

1990～1992年在大田条件下研究了分蘖衰亡过程中,主茎及各蘖位分蘖内源吲哚乙酸(IAA)、细胞分裂素类物质——玉米素核苷(ZR)和玉米素(Z)及脱落酸(ABA)的变化动态。结果表明,分蘖衰亡过程与内源激素变化有密切关系。不同蘖位分蘖虽然开始衰亡的时间不同,但开始形态衰亡之前都表现出共同规律,即各蘖位分蘖ZR Z的含量和ABA含量与主茎相应激素的差异显著加大,成为该蘖衰亡的先兆。在分蘖衰亡过程中,这种差异继续加大,直至该蘖枯亡。IAA的变化较晚发生,几乎与分蘖的形态衰亡同步进行。凡没有发生衰亡的分蘖,其内源激素含量与主茎的差异始终保持相对稳定,成为分蘖成穗的重要基础。研究初步认为,分蘖衰亡前ZR Z和ABA的这种变化是导致分蘖衰亡的主要原因,而IAA的变化则是伴随原因。因此,缩小主蘖间ZR Z和ABA含量上的差距是争取分蘖成穗的重要途径。

Studies on the Effects of Endogeneous Hormones in Winter Wheat Tillers during the Course of Senescence

The dynamics of endogeneous IAA, ZR Z, and ABA in the main stems and tillers at different position during the course of senescence were studied under field conditions from 1990 through 1992. The results are as follows: There is a close relationship between the endogeneous hormones and the senescence of the tillers. Although the starting time of senescence of tillers is different at different tiller positions, there appears the same behavior that seems to be the omen of senescence, i. e. a marked and ever-increasing tendency of differences between the ZR Z and ABA contents of the main stem and those of tillers, until the final dealth of the tiller. The change of the IAA content occurs later, almost Simultaneously with the course of senescence. Differences of endogeneous homone contents between healthy (not senescent)tillers and the main stem remain relatively stable, indicating that these hormones are important basis for the formation of spike from the tillers. It was concluded that the changes of the ZR Z and ABA contents of the tillers before senescence is the primary cause of the senescence of them, whereas the change of the IAA content is only a secondary cause. It is suggested, therefore, that reducing the differences between the ZR Z and ABA contents of the tillers and those of the main stem might be an important approach for better spike formation.