Silver nanoparticles enhanced shoot regeneration efficiency and limited some abnormal phenomena of African violet (Saintpaulia ionantha Wendl.) cultured in vitro

Abstract

This article investigated the effects of silver nanoparticles (AgNPs) on shoot regeneration, abnormal growth, ethylene (ET) gas fluctuations, and antioxidant enzyme activity during the shoot regeneration of African violet. The results showed that using the main leaf vein explant significantly improved shoot regeneration efficiency compared to the whole leaf explant, with a shoot regeneration rate of 66.00%, an average of 5.33 shoots per explant, and shoot height reaching 0.73 cm after eight weeks of cultivation. At shoot regeneration time, both the main leaf vein and whole leaf explants exhibited vitrification (20.00 and 19.67%, respectively), callus formation at the leaf edges (21.67 and 22.33%, respectively), necrosis (14.67 and 12.33%, respectively), and browning of explants and the culture medium (20.33 and 15.67%, respectively). Furthermore, adding 2 mg/l AgNPs into the regeneration environment enhanced shoot regeneration efficiency and growth, mitigated vitrification, callus formation, necrosis, browning of explants and the culture medium, reduced ethylene gas accumulation and increased the activities of ascorbate peroxidase (APX), catalase (CAT) during African violet shoot regeneration.