Defense enzyme activities and biochemical variations of Pelargonium zonale in response to nanosilver application and dark storage

Pelargonium petal abscission and ethylene-induced leaf senescence are major problems that reduce the longevity of plants. This study was carried out to determine the poststorage influence of nanosilver (NS) particle (0, 20, 40, 60, and 80 mg L-1) application during dark storage period on chlorophyll and carotenoid pigments, malondialdehyde (MDA) content, leaf protein and ethylene concentration, petal abscission, membrane stability index (MSI), and enzyme activity including ascorbate peroxidase (APX), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and beta-glucosidase (beta-GLU) in two Pelargonium pot plants of the cultivars Flowerfairy and Foxi. Enhanced photosynthetic pigment contents were recorded in leaves of both NS-treated cultivars when compared to the control. In both cultivars, MDA content decreased significantly with the increase of NS concentration up to 60 mg L-1, and then a rapid increase followed at 80 mg L-1. NS treatments markedly decreased petal abscission compared to the control. Enzymes activities were affected differently by various NS concentrations. The highest APX activity was observed at 40 mg L-1 NS concentration, but specific activities of SOD and POD increased to a maximum level at 60 mg L-1 in both cultivars. CAT activity was pronounced at 20 mg L-1 and 40 mg L-1 NS treatments in Flowerfairy and Foxi, respectively. Both under control conditions and at the highest NS concentration, beta-GLU showed lower activity than other NS levels. It was suggested for the first time that NS extended petal longevity and improved defense enzyme activities of Pelargonium pot plants under dark storage conditions.