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Submitted to: Journal of Environmental Horticulture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/25/2003 Publication Date: 12/1/2003 Citation: SCAGEL, C.F. INOCULATION WITH ARBUSCULAR MYCORRHIZAL FUNGI ALTERS NUTRIENT ALLOCATION AND FLOWERING OF FREESIA X HYBRIDA. JOURNAL OF ENVIRONMENTAL HORTICULTURE. 2003. 21(4): 196-205. Interpretive Summary: A balance between resources allocated to flowering and corm production is necessary for maximum productivity and quality of geophytes, such as Freesia, used for both flower and corm production. The symbiotic relationship between arbuscular mycorrhizal fungi (AMF) and their plant symbiont alters several aspects of plant development and growth via changes in mineral uptake and biomass partitioning that can differentially influence productivity and quality of corm crops. Addition of AMF to the growing medium of different Freesia x hybrida varieties alters aspects of flower production, corm production, and corm composition during two growth cycles after inoculation. There may also be other organisms associated with AMF inoculum that have beneficial effects on the growth and productivity of Freesia. While inoculation can promote shoot and flower emergence and increase the weight of daughter corms produced at the end of the growing cycle, other responses to AMF vary with Freesia variety and whether or not the growth medium is pasteurized. Technical Abstract: We assessed whether inoculation with arbuscular mycorrhizal fungi (AMF) of corms from three different Freesia x hybrida varieties grown in pasteurized or non-pasteurized soil alters aspects of flower and corm production during two growth cycles after inoculation. Shoots on AMF-inoculated plants emerged approximately 2 to 3 days earlier than shoots on non-inoculated plants. AMF had no influence on flower opening in the first growth cycle, but inoculated plants produced flowers approximately 20 days earlier than non-inoculated plants in the second growth cycle. When grown in non-pasteurized soil, inoculated plants produced more leaves, flowers, inflorescences, and flowers per inflorescence than non-inoculated plants. AMF-inoculated plants produced heavier daughter corms than non-inoculated plants. Inoculation increased the number of cormlets produced by two of the three varieties, however only one variety produced larger cormlets when inoculated. AMF-inoculated plants produced corms with protein, amino acid, and sugar concentrations and contents equal to or higher than corms from non-inoculated plants. Inoculation altered aspects of plant morphology and biomass partitioning important to flower and corm production of Freesia . Other soil organisms associated with non-pasteurized soil, and washings from AMF inoculum also play a role in the response of Freesia to AMF inoculation. |
