Abscisic acid acts essentially on stomata, not on the xylem, to improve drought resistance in tomato
Abscisic acid acts essentially on stomata, not on the xylem, to improve drought resistance in tomato
复制标题
DOI：
10.1111/pce.14676
复制
发表时间：
2023-08-01
影响因子：
7.3
通讯作者：
Cardoso, Amanda A.
中科院分区：
文献类型：
--
作者：
Haverroth, Eduardo J.;Oliveira, Leonardo A.;Cardoso, Amanda A.
抗旱性是植物在水分限制环境下生产所必需的。脱落酸（阿坝）在气孔中起着重要的作用，但其对气孔以外的水力功能的影响却研究得很少。我们选择了不同的基因型，他们的能力积累脱落阿坝，以调查其在干旱引起的功能障碍的作用。所有基因型表现出相似的叶和茎栓塞的阻力，无论阿坝水平的差异。叶片水力阻力也相似。差异只观察到两个极端的基因型：sitiens（坐，一个强大的ABA缺陷型突变体）和SP12（一个转基因株系，组成性overaccumulated阿坝），其中的水势诱导50%栓塞是0.25 MPa低于SP12比在坐。最大气孔和最小叶片电导率显着低于植物阿坝（野生型[WT]和SP12）比ABA缺乏突变体。不同基因型间气体交换的变化与阿坝水平和气孔密度和大小的差异有关。阿坝较高的植物水分损失较低，这意味着栓塞相关的致死水势发生在SP12植物干旱期间较晚，其次是WT，然后是ABA缺陷型突变体。因此，阿坝增强抗旱性的主要途径是通过降低失水，从而延缓脱水和水力功能障碍。
Drought resistance is essential for plant production under water-limiting environments. Abscisic acid (ABA) plays a critical role in stomata but its impact on hydraulic function beyond the stomata is far less studied. We selected genotypes differing in their ability to accumulate ABA to investigate its role in drought-induced dysfunction. All genotypes exhibited similar leaf and stem embolism resistance regardless of differences in ABA levels. Their leaf hydraulic resistance was also similar. Differences were only observed between the two extreme genotypes: sitiens (sit; a strong ABA-deficient mutant) and sp12 (a transgenic line that constitutively overaccumulates ABA), where the water potential inducing 50% embolism was 0.25 MPa lower in sp12 than in sit. Maximum stomatal and minimum leaf conductances were considerably lower in plants with higher ABA (wild type [WT] and sp12) than in ABA-deficient mutants. Variations in gas exchange across genotypes were associated with ABA levels and differences in stomatal density and size. The lower water loss in plants with higher ABA meant that lethal water potentials associated with embolism occurred later during drought in sp12 plants, followed by WT, and then by the ABA-deficient mutants. Therefore, the primary pathway by which ABA enhances drought resistance is via declines in water loss, which delays dehydration and hydraulic dysfunction.