激勃素於果樹開花誘導中扮演之角色

The Role of Gibberellins in Flower Induction of Fruit Trees

激勃素（Gibberellins, GAs）是模式植物阿拉伯芥的促進開花物質，在許多多年生的裸子植物也是如此。但在多年生的果樹中，有些研究指出GAs是開花的抑制物質，但也有其他試驗觀察到GAs會促進開花。造成這樣差異，可能是因多年生果樹開花過程，是由一連串且長時間的變化來完成，而在這樣的長時間中，包含了數個不同的階段，在不同的階段中，GAs的效用或許不同，但在研究過程中，不論是以外施GAs物質、分析內生GAs含量、轉入GAs合成相關的基因等方式來研究，由於研究人員只能在特定的時間點做處理或觀察，無法完全掌控到每個時間點，所以得到不同的結論。但大體而言，GAs對果樹開花誘導的影響，是因GAs會促進芽體萌動或進行營養生長，進而影響到花芽的誘導及發育，或是促使芽體發育成一個較偏向營養生長的無限花序或帶葉花序，而非直接對花芽誘導進行抑制。 Gibberellins (GAs) can promote flowering in the model plant Arabidopsis and in Gymnosperm plants. However, GAs have multi-functions in perennial fruit trees. Reports on the effects of GAs on flowering in fruit trees are often conflicting in that some showed promoting while others showed inhibiting flowering. The inconsistencies in these previous studied can be explained by inadequate analysis, particularly failure to determine that the effects of GAs were on 'vegetative' or 'flowering' phases. Researches including GAs application, analyses of the endogenous GAs content, and transferring related genes of GAs synthesis all worked on a specific phase stage, and thus led to different results. In generally, the effects of GAs on flower induction result from the promotion of bud breaking or vegetative growth and consequently affect the floral induction and development. GAs may induce the development of the infinite vegetative or leafy inflorescence, rather than directly suppress the flower bud formation.