Mycorrhizal fungi inoculation and phosphorus fertilizer on growth, essential oil production and nutrient uptake in peppermint (Mentha piperita L.)

Abstract

This study evaluated the effects of inoculation with the arbuscular mycorrhizal fungi <i>Glomus mosseae</i>, <i>Glomus intraradices</i> A<SUB>4</SUB> and <i>Glomus intraradices</i> B<SUB>1</SUB> and two phosphorus levels (10 and 40 mg kg<SUP>-1</SUP>) on root colonization, plant growth, nutrient uptake and essential oil content in <i>Mentha piperita</i> L. The experiment was carried out in a greenhouse, in 4x2 factorial arrangement, in completely randomized design. At sixty days after transplanting, the mycorrhizal plants had significantly higher fresh matter, dry matter and leaf area compared to non-mycorrhizal plants. The inoculation increased P, K and Ca levels in the shoot which were higher under 40 mg P kg<SUP>-1</SUP> of soil. Plants grown with 40 mg P kg<SUP>-1</SUP> soil increased the essential oil yield per plant by about 40- 50% compared to those cultivated with 10 mg P kg<SUP>-1</SUP>, regardless of the mycorrhizal treatment. Among the studied fungal species, inoculation with <i>G. intraradices</i> A<SUB>4</SUB> and a high level of P significantly increased plant growth and essential oil yield, compared to the other studied mycorrhizal fungal species. In conclusion, inoculation of arbuscular mycorrhizal fungi into peppermint plants is a feasible alternative to increase the essential oil production and reduce the use of fertilizers required to obtain economic production of peppermint under phosphorus-deficient soil condition.

Este estudo avaliou os efeitos da inoculagáo de fungos micorrízicos arbusculares i>Glomus mosseae</i>, <i>Glomus intraradices</i> A<SUB>4</SUB> e <i>Glomus intraradices</i> B<SUB>1</SUB> e duas doses de fósforo (10 e 40 mg kg<SUP>-1</SUP>) sobre a colonizagáo radicular, crescimento, absorgáo de nutrientes e óleos essenciais em <i>Mentha piperita</i> L. O estudo foi conduzido em casa de vegetagáo no delineamento inteiramente casualizado em esquema fatorial 4x2. Sessenta dias após o transplants, as plantas micorrizadas apresentaram massa fresca, massa seca, e área foliar significativamente maiorem comparagao as nao-micorrizadas. A inoculagáo aumentou oteorde P, Ke Ca na parte aérea sendo superiores em 40 mg P kg<SUP>-1</SUP> de solo. As plantas cultivadas com 40 mg P kg<SUP>-1</SUP> de solo aumentaram a produgáo de óleo essencial por planta cerca de 40-50% em relagáo ás cultivadas com 10 mg de P kg<SUP>-1</SUP>, independentemente da micorrizagáo. Dentre as espécies fúngicas estudadas, a inoculagáo com <i>G. intraradices</i> A<SUB>4</SUB>, e com um elevado nivel de P, aumentou significativamente o crescimento e rendimiento de óleos essenciais em comparagáo com outras espécies de fungos micorrízicos estudados. Em conclusáo, a inoculagáo dos fungos micorrízicos arbusculares em plantas de hortelá é urna alternativa viável para aumentar a produgáo de óleos essenciais e reduzir o uso de fertilizantes necessários para a produgáo económica de hortelá-pimenta com deficiencia de fósforo no solo.