Molecular Plant Physiology Research Group, Department of Experimental Botany, University of Nijmegen, Toernooiveld, 6525 ED Nijmegen, The Netherlands.
Plant Physiol. 1991 Aug;96(4):1131-5. doi: 10.1104/pp.96.4.1131.
The in vitro regeneration of flower buds was studied in pedicel explants from tobacco (Nicotiana tabacum L., cv Petit Havana) transformed with Agrobacterium rhizogenes, pRi 1855 (agropine type). At a low concentration (0.1 micromolar) of 1-naphthalene-acetic acid, pedicel strips from phenotypically aberrant plants regenerated two to three times more flower buds than explants from untransformed tobacco. Intermediate bud numbers were observed in transformants with a less extreme phenotype. The results can be explained by an increased sensitivity of the transformed explants to auxin with respect to flower bud regeneration. The effect of transformation on the auxin response is fully accounted for by the absence of a negative interaction of endogenous ethylene with 1-naphthaleneacetic acid, a phenomenon normally encountered in untransformed tissues. Three observations led to this conclusion. Application of 1 micromolar AgNO(3) to untransformed explants increased the number of flower buds to the level observed in transformed tissues but had no effect on transformed pedicel strips; exposure to 10 microliters per liter ethylene strongly reduced the response to auxin at all concentrations in untransformed explants but was almost ineffective in the transformed tissues; and endogenous ethylene synthesis occurred at the same rate in both types of explants.
在根癌农杆菌转化的烟草（Nicotiana tabacum L.，cv Petit Havana）花梗外植体中研究了花芽的离体再生，pRi 1855（胭脂碱型）。在 0.1 微摩尔低浓度的 1-萘乙酸作用下，表型异常的植株花梗外植体再生的花芽数量比未转化的烟草外植体多 2 到 3 倍。表型不那么极端的转化体中观察到中间芽数。这一结果可以通过转化外植体对生长素的敏感性增加来解释，这与花器官再生有关。转化对生长素反应的影响完全由内源乙烯与 1-萘乙酸之间不存在负相互作用来解释，这种现象在未转化的组织中通常会遇到。有三个观察结果得出了这个结论。将 1 微摩尔 AgNO3 应用于未转化的外植体可将花芽数量增加到转化组织中观察到的水平，但对转化的花梗外植体没有影响；在未转化的外植体中，10 微升/升乙烯强烈降低了所有浓度下对生长素的反应，但在转化组织中几乎无效；两种类型的外植体中内源乙烯的合成速率相同。
