VESICULAR-ARBUSCULAR MYCORRHIZAL PEAT-BASED SUBSTRATES ENHANCE SYMBIOSIS ESTABLISHMENT AND GROWTH OF 3 MICROPROPAGATED SPECIES

Micropropagated plantlets of Gerbera jamesonii H. Bolus ex Hook. F. 'Terra Mix', Nephrolepis exaltata (L.) Schott 'Florida Ruffles', and Syngonium podophyllum Schott 'White Butterfly' were inoculated with two vesicular-arbuscular mycorrhizal (VAM) fungi, Glomus intraradices Schenck and Smith and G. vesiculiferum Gerderman and Trappe. They were potted in three peat-based media to determine the effects of mycorrhizal peat substrate on acclimatization and subsequent growth of micropropagated plantlets under greenhouse conditions. Symbiosis was established between the three ornamental species and VAM fungi within 4 to 8 weeks of culture in the greenhouse, but not during acclimatization. Mortality of Gerbera and Nephrolepis mycorrhizal plantlets was reduced at week 8 compared to the noninoculated control. A peat-based substrate low in P and with good aeration improved VAM fungi spread and efficiency. Mycorrhizal substrates had a longterm benefit of increasing leaf and root dry weight of Gerbera and Nephrolepis. Mycorrhizal Gerbera plants flowered significantly faster than non-mycorrhizal plants.