【作者】 叶梅荣；

【导师】 夏凯；

【作者基本信息】 南京农业大学 ， 植物学， 2006， 硕士

【摘要】 本文以水仙（Narcissus tazetta var．Chinensis）花茎和大蒜（Allium sativumL．）蒜薹为材料，通过外源生长素吲哚乙酸吲哚-3-乙酸（Indole-3-aceticacid，IAA）和赤霉素（gibberellin A₃，GA₃）处理，结合内源激素分析，研究了这两种激素对水仙花茎和大蒜蒜薹伸长生长的效应，以及它们之间的相互作用。结果表明来源于水仙花苞和大蒜花苞的生长素为控制花茎和蒜薹伸长的主控因子。切去水仙和大蒜花苞（去顶）后明显抑制花茎和蒜薹的伸长生长，去顶后48h，其伸长率分别仅为留顶的34.32％和50.06％，说明花茎和蒜薹的伸长受其上部的花苞控制。在去顶花茎和蒜薹的切口位置分别施用50μmol·L^-1和250μmol·L^-1IAA均能提高去顶花茎和蒜薹的伸长率，处理后48h，伸长率分别为15.82％和56.40％；并且在去顶花茎和蒜薹的切口位置分别施用150μmol·L^-1 GA₃均能提高去顶花茎和蒜薹的伸长率，处理后48h，伸长率分别为10.11％和31.12％，而去顶对照花茎和蒜薹的伸长率分别仅为6.615％和21.30％。其中IAA的促进作用高于GA₃，但IAA处理去顶花茎明显小于未处理的留顶花茎的伸长率（22.6％），而IAA处理去顶蒜薹持平或略超过未处理的留顶蒜薹的伸长率（54.33％）；GA₃处理的去顶花茎和蒜薹的伸长率分别明显小于未处理留顶花茎和蒜薹的伸长率。在去顶花茎和蒜薹的切口位置分别施用130μmol·L^-1赤霉素合成扣制剂烯效唑（uniconazole，S-3307）均能抑制去顶花茎和蒜薹的伸长，暗示内源活性GA对花茎和蒜薹伸长起作用。在不去顶的花苞基部施用300μmol·L^-1生长素极性运输抑制剂2，3，5-三碘苯甲酸（2，3，5-tri iodobenzoic acid，TIBA），降低了其下部花茎和蒜薹的伸长率，其伸长率分别仅为未处理花茎和蒜薹的62.61％和71.35％。说明TIBA抑制生长素的极性运输，分别抑制花茎和蒜薹的伸长，暗示来源于花苞的生长素对花茎和蒜薹的伸长起重要作用。内源激素分析表明，去顶后花茎和蒜薹中IAA和GA₁₊₃含量急剧下降，I从含量分别比留顶正常花茎和蒜薹的下降6.68倍和7.15倍，GA₁₊₃含量下降了7.28倍和7.27倍，表明花苞为维持花茎和蒜薹中高水平的IAA和活性GA所必需。在花苞基部施用TIBA，不仅显著降低花茎和蒜薹中IAA的水平，分别为留顶正常花茎和蒜薹的51.4％和57.88％；而且也降低花茎中GA₁₊₃的水平，分别为留顶正常花茎和蒜薹的72.2％和80.27％，说明花苞中的IAA通过极性运输提供给花茎和蒜薹，且花苞中的IAA对维持活性GA水平起重要作用。外源IAA处理不仅增加去项花茎和蒜薹内源IAA本身的含量，分别为去顶对照花茎和蒜薹的6.45倍和19.87倍；而且也显著增加去顶花茎和蒜薹内源的GA₁₊₃的含量，分别为去顶对照花茎和蒜薹的4.32倍和3.86倍。外源GA₃处理对去顶花茎和蒜薹的内源IAA水平没有影响，但使去顶花茎和蒜薹的内源GA₁₊₃含量分别增加到去顶对照的5.52倍和4.01倍。离体花茎和蒜薹切段实验得到相似的结果。综上述结果表明来自花苞的IAA能维持花茎和蒜薹中活性GA的水平，由此共同发挥出调控花茎和蒜薹伸长的作用。更多还原

【Abstract】 By the supply of exogenous indole-3-acetic acid （IAA） and gibberellin A₃ （GA₃）, and the quantification of endogenous hormones, the effects of IAA and GA3, as well as the relationships between two hormones were examined in Narcissus tazetta var. and Allium sativum L. on the control of the elongation of the pedicel and garlic bolt. The results showed that auxin derived from their inflorescence respectively dominated the pedicel and garlic bolt elongation.The elongation of both pedicels and garlic bolts were inhibited by the decapitation （removing inflorescence）. After 48 h decapitation, the elongation rates of pedicels and garlic bolts decreased to 34.32% and 50.06% of the un-decapitated control respectively, these indicated that the elongation of pedicels and garlic bolts were controlled by their infloresence. After decapitation, the elongation rates of pedicels and garlic bolts were 15.82% and 56.4% respectively by apart performing exogenous 50μmol·L^-1 and 250μmol·L^-1 IAA at the excised for 48 h; The elongation rates of both pedicels and garlic bolts were 10.11% and 31.12% after treatment of 150μmol·L^-1 exogenous GA₃ for 48 h at the excised site; While the elongation rates of the decapitated control were 6.66% and 21.30% respectively for 48 h. IAA showed a stronger promotion effect than GA₃ in these processes. The elongation rates of decapitated pedicels treated with IAA was lower than the un-decapitated’s, while the elongation rates of decapitated garlic bolts treated with IAA was equal to or higher than the un-decapitated’s. The elongation rates of decapitated pedicel and garlic bolts treated with GA₃ were lower than the un-decapitated’s respectively. Application of 130μmol·L^-1 uniconazole （S-3307）, a gibberellin biosynthesis inhibitor, at the excised site, decreased the pedicel and garlic bolt elongation, indicating that endogenous active GA promoted the elongation of pedicels and garlic bolts. Application of 2,3,5-triiodobenzoic acid （TIBA）, a polar auxin transport inhibitor, at the base of inflorescence, respectively, decreased the elongation rates of pedicel and garlic bolt to a level of 62.61% and 71.35% of the un-decapitated control, indicating that IAA derived from inflorescence controlled the pedicel and garlic bolt elongation.The results of plant hormones analysis revealed that decapitation reduced both endogenous IAA and GA₁₊₃ content in the pedicel and garlic bolt, and IAA decreased by 6.68, 7.15 -fold of the un-decapitated control, respectively; while GA₁₊₃ decreased to a level of 7.15, 7.27-fold of the un-decapitated control, respectively. These indicated that the inflorescence should be important to maintain high level of IAA and active GA in the pedicel and garlic bolt. Application of TIBA, at the base of inflorescence not only decreased IAA content but also reduced GA₁₊₃ content in pedicel and garlic bolt, IAA decreased to a level of 51.4%, 57.88% of the un-decapitated control respectively, while GA₁₊₃ decreased to a level of 72.2%, 80.27% of the un-decapitated control, respectively. These indicated that IAA derived from inflorescence to the pedicel and garlic bolt by a porlar auxin transport. And IAA was important to maintain content of active GA in the pedicel and garlic bolt respectively. Application of IAA increased both IAA and GA₁₊₃ content in the pedicel and garlic bolt, IAA content increased to a level of 6.45, 19.87-fold of the decapitated control respectively, while GA₁₊₃ content increased to a level of 4.32, 3.86-fold of the decapitated control respectively. Endogenous IAA content was not affected by applying GA₃, But GA₁₊₃ content increased in the pedicel and garlic bolt, to a level of 5.52, 4.01-fold of the decapitated control. The results of excised pedicel and garlic bolt segments resembled to the above. All together, these data suggest that IAA derived from inflorescence dominate pedicel and garlic bolt elongation by maintaining content active GA in the pedicel and garlic bolt.更多还原