2，4-D Treatment Could Maintain the Development of Siliques from Emasculated Flowers of an Auxin-resistant Mutant axr1-12

Abstract: An auxin-resistant mutant axr1-12 was discovered twenty years ago， the mechanism of its abnormal silique development related to auxin signaling is still unclear. The effects of auxin (2，4-D)， gibberellin (GA₃) and cytokinin (BAP) on emasculated flowers of axr1-12 and its wild type plant Columbia were comparatively studied. Silique development from emasculated flower of axr1-12 could be significantly stimulated with 1 μl of 2，4-D (0.1 nmol/pistil) while that of Columbia was severely inhibited. Additionally and interestingly， 2，4-D could also promote axr1-12 ovule developing into pseudo-seed. The silique elongation of emasculated flower in both axr1-12 and Columbia could be greatly stimulated with 1 μl of GA₃ (0.1-10.0 nmol/pistil). BAP only presented a very weak stimulation on Columbia' silique development. The application of 2，4-D (0.1 nmol/pistil) along with GA₃ (1.0 nmol/pistil) demonstrated an additive effect on the elongation of emasculated pistil in axr1-12. Taken together， our results suggest that 2，4-D obviously stimulated silique elongation through parthenogenesis in the mutant axr1-12 and GA₃ was also important in this process

CSTR: 32200.14.cjcb.2008.06.0025