Climate change threatens food security, and plant science researchers have investigated methods of sustaining crop yield under drought. One approach has been to overproduce abscisic acid (ABA) to enhance water use efficiency. However, the concomitant effects of ABA overproduction on plant vascular system functioning are critical as it influences vulnerability to xylem hydraulic failure. We investigated these effects by comparing physiological and hydraulic responses to water deficit between a tomato (Solanum lycopersicum) wild type control (WT) and a transgenic line overproducing ABA (sp12). Under well-watered conditions, the sp12 line displayed similar growth rate and greater water use efficiency by operating at lower maximum stomatal conductance. X-ray microtomography revealed that sp12 was significantly more vulnerable to xylem embolism, resulting in a reduced hydraulic safety margin. We also observed a significant ontogenic effect on vulnerability to xylem embolism for both WT and sp12. This study demonstrates that the greater water use efficiency in the tomato ABA overproducing line is associated with higher vulnerability of the vascular system to embolism and a higher risk of hydraulic failure. Integrating hydraulic traits into breeding programmes represents a critical step for effectively managing a crop's ability to maintain hydraulic conductivity and productivity under water deficit.

中文翻译：

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转基因番茄植株中脱落酸的过度积累增加了水力衰竭的风险。

气候变化威胁着粮食安全，植物科学研究者已经研究了干旱条件下维持作物单产的方法。一种方法是过量生产脱落酸（ABA）以提高用水效率。但是，ABA过量生产对植物维管系统功能的伴随影响至关重要，因为它影响木质部水力衰竭的脆弱性。我们通过比较番茄（Solanum lycopersicum）野生型对照（WT）和过量生产ABA（sp12）的转基因品系之间对水分缺乏的生理和水力响应，研究了这些影响。在灌溉条件良好的条件下，sp12品系通过在较低的最大气孔导度下运行，表现出相似的增长率和更高的用水效率。X射线显微照片显示，sp12明显更容易受到木质部栓塞的影响，导致液压安全裕度降低。我们还观察到WT和sp12对木质部栓塞的脆弱性具有显着的本体作用。这项研究表明，番茄ABA超产系中较高的水分利用效率与血管系统对栓塞的更高脆弱性和更高的水力衰竭风险相关。将水力性状纳入育种程序是有效管理作物在缺水条件下保持水力传导性和生产力的关键步骤。这项研究表明，番茄ABA超产系中较高的水分利用效率与血管系统对栓塞的更高脆弱性和更高的水力衰竭风险相关。将水力性状纳入育种程序是有效管理作物在缺水条件下保持水力传导性和生产力的关键步骤。这项研究表明，番茄ABA超产系中较高的水分利用效率与血管系统对栓塞的更高脆弱性和更高的水力衰竭风险相关。将水力性状纳入育种程序是有效管理作物在缺水条件下保持水力传导性和生产力的关键步骤。