Author(s): Carvalho, Dália R.A. ; Vasconcelos, Marta W. ; Lee, Sangseok ; Koning-Boucoiran, Carole F.S. ; Vreugdenhil, Dick ; Krens, Frans A. ; Heuvelink, Ep ; Carvalho, Susana M. P.
Date: 2016
Persistent ID: http://hdl.handle.net/10400.14/23122
Origin: Veritati - Repositório Institucional da Universidade Católica Portuguesa
Subject(s): Abscisic acid; Stomatal anatomy; Tetraploid roses; Vapor pressure deficit; Water loss
tHigh relative air humidity (RH ≥ 85%) during growth disturbs stomatal functioning, resulting in excessivewater loss in conditions of high evaporative demand. We investigated the expression of nine abscisic acid(ABA)-related genes (involved in ABA biosynthesis, oxidation and conjugation) and two non-ABA relatedgenes (involved in the water stress response) aiming to better understand the mechanisms underlyingcontrasting stomatal functioning in plants grown at high RH. Four rose genotypes with contrasting sen-sitivity to high RH (one sensitive, one tolerant and two intermediate) were grown at moderate (62 ± 3%)or high (89 ± 4%) RH. The sensitive genotype grown at high RH showed a significantly higher stomatalconductance (gs) and water loss in response to closing stimuli as compared to the other genotypes. More-over, high RH reduced the leaf ABA concentration and its metabolites to a greater extent in the sensitivegenotype as compared to the tolerant one. The large majority of the studied genes had a relevant role onstomatal functioning (NCED1, UGT75B2, BG2, OST1, ABF3 and Rh-APX) while two others showed a minorcontribution (CYP707A3 and BG1) and AAO3, CYP707A1 and DREB1B did not contribute to the tolerancetrait. These results show that multiple genes form a highly complex regulatory network acting togethertowards the genotypic tolerance to high RH.
