Abscisic acid (ABA) is found in a wide diversity of organisms, yet we know most about the hormonal action of this compound in the ecologically dominant and economically important angiosperms. In angiosperms, ABA regulates a suite of critical responses from desiccation tolerance through to seed dormancy and stomatal closure. Work exploring the function of key genes in the ABA signalling pathway of angiosperms has revealed that this signal transduction pathway is ancient, yet considerable change in the physiological roles of this hormone have occurred over geological time. With recent advances in our capacity to characterise gene function in non-angiosperms we are on the cusp of revealing the origins of this critical hormonal signalling pathway in plants, and understanding how a simple hormone may have shaped land plant diversity, ecology and adaptation over the past 500 million years.

脱落酸 (ABA) 存在于多种生物体中，但我们最了解这种化合物在生态优势和经济上重要的被子植物中的激素作用。在被子植物中，ABA 调节从干燥耐受性到种子休眠和气孔关闭的一系列关键反应。探索被子植物 ABA 信号通路中关键基因的功能的工作表明，这种信号转导通路很古老，但随着地质时间的推移，这种激素的生理作用发生了相当大的变化。随着我们表征非被子植物基因功能的能力的最新进展，我们正处于揭示植物中这一关键激素信号传导途径的起源的风口浪尖，并了解一种简单的激素如何影响陆地植物多样性，