Methyl jasmonate enhances vase life and alters physiological and molecular responses in tree peony 'Luoyang Hong' cut flowers

Abstract

Vase life of tree peony cut flower is very limited, the extension of cut flower opening process is an effective way to prolong vase life. The present study was carried out to observe the morphological characteristics of cut flowers during vase insertion by treating with 10 μmol L⁻¹ methyl jasmonate (MeJA), using a representative variety of tree peony cut flower ‘Luoyang Hong’ as the material. Changes in osmoregulatory substances, antioxidant enzyme activities, antioxidant and reactive oxygen species content, and endogenous hormone content were measured, and the expression patterns of genes related to ethylene, abscisic acid synthesis and signalling pathways, and the senescence marker gene SAG12 were analysed by qRT-PCR. The results showed that exogenous MeJA could delay the opening process of tree peony ‘Luoyang Hong’ cut flowers, increase the fresh weight of cut flowers and reduce the flower diameter; Increased superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activities, increased osmoregulatory substances such as soluble sugars and soluble proteins, increased glutathione (GSH), ascorbic acid (AsA), total phenolics and total flavonoids, decreased malondialdehyde (MDA), H₂O₂ and O₂^-contents, and decreased endogenous ethylene precursor ACC and abscisic acid (ABA) content; Down-regulated the expression of ethylene synthesis gene PsACS, PsACO and ethylene signalling genes PsETR1, PsEIN3 and PsERF1, as well as down-regulated the expression of ABA signalling PsPYL8, PsPYR1 and PsABF2 genes. These results indicate that 10 μmol L⁻¹ MeJA can effectively delay the senescence of ‘Luoyang Hong’ and prolong the bottle insertion time.