Postharvest Assessment of Lignifying Enzymes Activity, Flower Stem Lignification and Bending Disorder of Gerbera Cut Flower

Scape bending disorder is the most important factors affecting the postharvest loss of gerbera cut flowers. One of the ultimate reasons for gerbera stem bending is deformation of lignin, with structural functions and defensive mechanisms. This postharvest experiment was conducted to evaluate the role of phenylalanine ammonia lyase (PAL) and peroxidise (POD) enzymes activity in stem bending of two sensitive (‘Beaudine’) and resistant cultivars (‘Aqua’). This experiment was based on a completely randomized design with three replications over eight days. Results showed the significant effects of cultivar on stem bending percentage, total phenol content, PAL and POD enzymes activity and lignin content (P < 0.05). The ‘Aqua’ had the highest phenol and lignin content and the lowest percentage of stem bending as a result; the maximum and the minimum PAL and POD enzymes activity was observed in resistant and sensitive cultivars, respectively. Based on the results, induction of PAL and POD enzymes activity, and consequently lignin formation, could have direct effects on stem strength and as a result reduce gerbera stem bending disorder.