Phytohormone profile in Lactuca sativa and Brassica oleracea plants grown under Zn deficiency

Abstract

Phytohormones are structurally diverse compounds involved in multiple processes within plants, in addition to controlling plant growth they are necessary in stress response. Zn is an essential micronutrient for plant and its deficiency produces large economic losses in crops. Therefore, the purpose of this study was to analyze the role of phytohormones in Zn deficiency response of two species of great agronomic interest like Lactuca sativa and Brassica oleracea. For this, plants of these species were grown in hydroponics with different Zn doses: 10 µM Zn as control and 0.1 µM Zn as deficiency treatment and phytohormone concentration was determined by U-HPLC-MS. Zn deficiency produced a substantial loss of biomass in L. sativa plants that was correlated with a decline in growth promoting hormones like indole-3-acetic acid (IAA), cytokinins (CKs) and gibberellins (GAs), however these hormones increased or maintained their concentrations in B. oleracea and could help to maintain the biomass in this species. A decrease in concentration of stress signaling hormones like ethylene precursor aminocyclopropane-1-carboxylic acid (ACC), abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) and also CKs might be involved in Zn absorption in L. sativa while an increase in GA4, isopentenyl adenine (iP) and ACC and a decrease in JA and SA might contribute to the better Zn utilization efficiency (ZnUtE) observed in B. oleracea plants.