Eduardo Haverroth obtained his PhD in Plant physiology at Universidade Federal de Vicosa. Currently, Haverroth is a postdoctoral researcher at North Carolina University. His research focuses on studying plant physiological and anatomical traits related to abiotic stresses, such as waterlogging, drought, and high temperature. The findings of his research can be useful in addressing the challenge of food production in a scenario of climate change. He is the Project Manager of AI2EAR, an NSF AccelNet Network of Networks that aims to integrate Engineering, Plant Sciences, and Agriculture using Artificial Intelligence.
Abscisic acid acts essentially on stomata, not on xylem, to improve drought tolerance
E. J. HAVERROTH, L. A. OLIVEIRA, M. T. ANDRADE, M. TAGGART, S. A. M. MCADAM, A. ZSÖGÖN, A. J. THOMPSON, S. C.V. MARTINS, A. A. CARDOSO
Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, 27695, USA
Drought resistance is essential for plant production under water-limiting environments. Abscisic acid (ABA) plays a critical role in stomatal function during drought but its impact on hydraulic function beyond the stomata is less studied. We selected four tomato genotypes differing in their ability to accumulate ABA to investigate its role in drought-induced dysfunction. All genotypes displayed similar leaf and stem embolism resistance, along with comparable leaf hydraulic resistance. The only difference was observed between the two extreme genotypes: sitiens (sit; a strongly ABA-deficient mutant) and sp12 (a transgenic line that constitutively over-accumulates ABA). 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 biosynthesis (WT and sp12). Variations in gas exchange were associated with both ABA levels and differences in stomatal density and size. Plants with higher ABA biosynthesis exhibited lower water loss, delaying lethal water potentials associated with embolism during drought. In conclusion, ABA does not impact xylem embolism resistance; instead, its primary mechanism for enhancing drought tolerance involves reducing water loss, thus delaying dehydration and hydraulic dysfunction.