ARS | Publication request: STIMULATION OF SPEARMINT (MENTHA SPICATA L.) GROWTH AND MORPHOGENESIS BY AUTOCLAVED FUNGAL BIOMASS

Submitted to: Great Lakes Regional American Chemical Society Symposium
Publication Type: Abstract
Publication Acceptance Date: October 20, 2004
Publication Date: October 20, 2004
Citation: Khan, N.I., Tisserat, B., Berhow, M.A., Vaughn, S.F. 2004. Stimulation of spearmint (mentha spicata l.) growth and morphogenesis by autoclaved fungal biomass [abstract]. Great Lakes Regional American Chemical Society Symposium. p. 97.

Technical Abstract: Spearmint (Mentha spicata L.) oil contains carvone as a major component and is used primarily as a flavoring agent, carminative, antiseptic, and local anesthetic in cold and cough preparations. Fungal additives had been reported to enhance secondary metabolism in a variety of plant cells in suspension cultures. We studied the influence of autoclaved fungal biomass such as culture filtrate (CF), freeze dried mycelium (FDM), frozen mycelium (FM), and spore suspension (SS) on the growth, morphogenesis, and carvone production in spearmint plants. Fungal materials were either applied as a drench or spray on the plants. Spearmint plants (cv. 294099), drenched with spore suspensions (1 x 10**8/ml) of Aspergillus niger or Trichoderma reesei, showed no significant differences for fresh weights, shoot numbers, and leaf numbers compared to non-treated control. However, significantly higher carvone contents were observed in plants drenched with T. reesei SS compared to the other treatments (P=0.05). In general, regardless of spearmint cultivar (cvs. 294099 or 557807), plants sprayed with T. reesei or A. niger FDM, FM, CF, or SS exhibited higher fresh weights (121%), shoot numbers (131%), leaf numbers (128%), and root numbers (147%) compared to controls (P=0.05). This effect was generally not dose dependent, although we have not determined the minimum dose to initiate response yet. Carvone levels in fungal treated plants were comparable to non-treated controls. However, carvone level per plant was higher in treated plants due to their increased fresh weight. Dead fungal biomass improves growth, morphogenesis, and total secondary metabolite levels in spearmint.