Efficacy of MYKE® on in vitro growth of American elm (Ulmus americana)

Abstract

This thesis is an examination of the commercial product MYKE which is a perlite-peat mixture containing 7 spores/g of Glomus intraradices N.C Schenk & G.S. Sm., a vesicular-arbuscular mycorrhiza-forming fungus. Seeds of American elm (Ulmus americana L.) were aseptically geminated and forty seedlings planted in Erlenmeyer flasks containing a vermiculite-peat mixture (10:1) and supplemented with different amounts of MYKE. Ten flasks received no MYKE, ten flasks received 1 gram, ten flasks received 5 grams, and ten flasks received 25 grams. All flasks were incubated under fluorescent white lights for 3 months at 25°C. When seedlings were harvested, they were grouped according to treatment and photographed, then bagged, dried and weighed. A representative seedling from each group was stained with Trypan Blue. Results revealed that no spores had germinated as there was a lack of mycelium in the flasks and no colonization of the roots had occurred. It was found that increasing the amount of MYKE per flask caused a reduction in seedling growth. It was hypothesized that several factors may have resulted in lack of spore germination such as low light intensity affecting seedling growth and subsequently affecting quantity and quality of root exudates that would normally stimulate spores to germinate. The results of this experiment do not negate the potential benefits of vesicular-arbuscular mycorrhiza-forming fungi, especially in the urban landscape.