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

Submitted to: Phytochemical Society of North America Proceedings
Publication Type: Abstract
Publication Acceptance Date: August 13, 2003
Publication Date: August 13, 2003
Citation: Khan, N.I., Tisserat, B., Berhow, M.A., Vaughn, S.F. 2003. Stimulation of spearmint (Mentha spicata l.) growth and morphogenesis by autoclaved fungal fractions [abstract]. Phytochemical Society of North America. p. 31.

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 have been reported to enhance secondary metabolism in a variety of plant cells in suspension cultures. We studied the influence of autoclaved fractions of fungal cultures including culture filtrates (CF), freeze dried mycelia (FDM), frozen mycelia (FM), and spore suspensions (SS) on the growth, morphogenesis, and carvone production in spearmint plants. Fungal fractions were applied either as a drench or a spray on plants. Spearmint plants (cv. 294099), drenched with spore suspensions (1X108/ml) of Aspergillus niger or Trichoderma reesei, showed no significant differences for fresh weights, shoot numbers, and leaf numbers compared to non-treated control plants. 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 probably not dose dependent, although the minimum dose to initiate response has not yet been determined. Carvone levels in fungal treated plants were comparable to non-treated controls. However, total carvone levels per plant were higher in treated plants due to their increased fresh weights. Fungal culture fractions appear to offer promise in improving growth, morphogenesis, and total secondary metabolite production in treated plants.