Effect of exogenous putrescine on flower growth, post-harvest quality and root mycorrhizal development of gerbera (Gerbera jamesonii cv. Dune) cut flowers.

• Putrescine increases the rate of mycorrhiza colonization in the root. • Putrescine and mycorrhiza improved the quality of gerbera cut flowers. • Putrescine and mycorrhizal inoculation maintained the quality of gerbera cut flowers during vase life period. Effect of putrescine on the rate of mycorrhiza colonization in root and their effect on the growth and flowering process of gerbera 'Dune' was investigated in the form of factorial trial in a completely randomized design with three replications in a greenhouse. The factors were four concentrations of putrescine (0, 1, 2, and 4 mM) as foliar application and mycorrhizal fungus (without and with inoculation). The Mycorrhizal fungus was inoculated when plantlets transfer to pots, and two weeks after establishment; putrescine foliar application was performed every 15 days-interval for three months. Morphological and physiological characteristics measured in this research were included the number of flowers per plant, the time of bud formation until flowering, flower diameter, fresh and dry weight of flowers, flower longevity, total phenol, and leaf anthocyanin, as well as symbiosis percentages. The results showed that foliar application of putrescine increased mycorrhiza colonization in roots, and the highest colonization was obtained at the concentration of 2 mM putrescine application. Also, their interaction had a positive effect on other measured traits compared to the control. Putrescine and mycorrhiza increased the quality of gerbera cut flowers and reduced ions leakage, hydrogen peroxide, malondialdehyde, and lipoxygenase activity, and increased ascorbate peroxidase activity. [ABSTRACT FROM AUTHOR]