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Article|11 Sep 2019|OPEN
ABA-mediated regulation of leaf and root hydraulic conductance in tomato grown at elevated CO2 is associated with altered gene expression of aquaporins
Liang Fang1,2 , Lamis Osama Anwar Abdelhakim1 , Josefine Nymark Hegelund1 , Shenglan Li1 , Jie Liu1,3 , Xiaoying Peng1,4 , Xiangnan Li5 , Zhenhua Wei1,3 , Fulai Liu,1,3 ,
1Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Alle 13, 2630 Taastrup, Denmark
2Present address: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University & Research, PO Box 430, 6700 AK Wageningen, The Netherlands
3Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, 712100 Yangling, Shaanxi, China
4College of Bioscience and Biotechnology, Hunan Agricultural University, 410128 Changsha, Hunan, China
5Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 130102 Changchun, China
*Corresponding author. E-mail: fl@plen.ku.dk

Horticulture Research 6,
Article number: 104 (2019)
doi: https://doi.org/10.1038/s41438-019-0187-6
Views: 971

Received: 12 Apr 2019
Revised: 16 Jul 2019
Accepted: 03 Aug 2019
Published online: 11 Sep 2019

Abstract

Elevated CO2 concentration in the air (e[CO2]) decreases stomatal density (SD) and stomatal conductance (gs) where abscisic acid (ABA) may play a role, yet the underlying mechanism remains largely elusive. We investigated the effects of e[CO2] (800 ppm) on leaf gas exchange and water relations of two tomato (Solanum lycopersicum) genotypes, Ailsa Craig (WT) and its ABA-deficient mutant (flacca). Compared to plants grown at ambient CO2 (400 ppm), e[CO2] stimulated photosynthetic rate in both genotypes, while depressed the gs only in WT. SD showed a similar response to e[CO2] as gs, although the change was not significant. e[CO2] increased leaf and xylem ABA concentrations and xylem sap pH, where the increases were larger in WT than in flacca. Although leaf water potential was unaffected by CO2 growth environment, e[CO2] lowered osmotic potential, hence tended to increase turgor pressure particularly for WT. e[CO2] reduced hydraulic conductance of leaf and root in WT but not in flacca, which was associated with downregulation of gene expression of aquaporins. It is concluded that ABA-mediated regulation of gs, SD, and gene expression of aquaporins coordinates the whole-plant hydraulics of tomato grown at different CO2 environments.