Abstract Watsonia fourcadei is one of the widespread geophyte species of the fire-prone fynbos vegetation of South Africa that flowers profusely in the first year after a fire. Although much has been researched on fire-stimulated seed germination, the effect of wildfire on flower elicitation in fynbos geophytes is less well researched. Hence, a study was undertaken to investigate the role of gibberellic acid in stimulating flowering of W. fourcadei. The hypothesis tested was that the plant hormone gibberellic acid (GA3) stimulates W. fourcadei plants to flower in situ. Unburned plants were injected with 2 ml of a solution of 50 µg GA3/ml distilled water in early spring and their flowering percentage was three times higher than those of control plants that were injected with 2 ml of water, and the untreated plants. The flowering percentage of plants treated with GA3 was equal to those of the plants found in the adjacent burned area. The endogenous biosynthesis of gibberellic acid in the post-fire environment seems to play an important role in stimulating W. fourcadei to flower and the ecological significance of this conclusion is briefly discussed.

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关于 Watsoniafourcadei JW Mathews & L. Bolus 开花刺激的注意事项

摘要 Watsonia Fourcadei 是南非易发生火灾的 fynbos 植被中广泛分布的地生植物之一，在火灾后的第一年就会大量开花。尽管已经对火刺激种子萌发进行了很多研究，但对野火对 fynbos geophytes 开花的影响的研究较少。因此，进行了一项研究以调查赤霉酸在刺激 W.fourcadei 开花中的作用。测试的假设是植物激素赤霉酸 (GA3) 刺激 W.fourcadei 植物原位开花。未燃烧的植物在早春注射2 ml 50 µg GA3/ml 蒸馏水的溶液，其开花百分比是注射2 ml 水的对照植物和未处理植物的三倍。用 GA3 处理的植物的开花百分比等于在邻近燃烧区域发现的植物的开花百分比。火灾后环境中赤霉酸的内源生物合成似乎在刺激 W.fourcadei 开花方面发挥了重要作用，并简要讨论了这一结论的生态意义。