Drought is one of the major abiotic stresses affecting the productivity of Brassica crops. To understand the role of phytohormones in drought tolerance, we subjected Chinese cabbage (B. rapa ssp. pekinensis), white cabbage (B. oleracea var. capitata), and kale (B. oleracea var. acephala) to drought and examined the stress response on the physiological, biochemical and hormonal levels. The phytohormones abscisic acid (ABA), auxin indole-3-acetic acid (IAA), brassinosteroids (BRs), cytokinins (CKs), jasmonates (JAs), and salicylic acid (SA) were analyzed by ultra-high-performance liquid chromatography⁻tandem mass spectrometry (UHPLC-MS/MS). Based on the physiological and biochemical markers the Chinese cabbage exhibited the lowest tolerance, followed by the white cabbage, while the kale appeared to be the most tolerant to drought. The drought tolerance of the kale correlated with increased levels of SA, ABA, IAA, CKs iP(R) and cZ(R), and typhasterol (TY), a precursor of active BRs. In contrast, the drought sensitivity of the Chinese cabbage correlated with a significant increase in ABA, JAs and the active BRs castasterol (CS) and brassinolide (BL). The moderately tolerant white cabbage, positioned between the kale and Chinese cabbage, showed more similarity in terms of the phytohormone patterns with the kale. We concluded that the drought tolerance in Brassicaceae is mostly determined by the increased endogenous levels of IAA, CKs, ABA and SA and the decreased levels of active BRs.

Department of Biology Faculty of Science University of Zagreb Rooseveltov trg 6 Zagreb 10000 Croatia

Faculty of Humanities and Social Sciences and Faculty of Dental Medicine and Health Josip Juraj Strossmayer University of Osijek Lorenza Jägera 9 Osijek 31000 Croatia

Laboratory for Chemical Biology Department of Molecular Biology Ruđer Bošković Institute Bijenička cesta 54 Zagreb 10000 Croatia

Laboratory of Growth Regulators Centre of the Region Haná for Biotechnological and Agricultural Research Faculty of Science of Palacký University and Institute of Experimental Botany of the Czech Academy of Sciences Šlechtitelů 27 Olomouc 78371 Czech Republic

Citace poskytuje Crossref.org