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Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/1/2006 Publication Date: 6/1/2006 Citation: Scagel, C.F., Schreiner, R.P. 2006. Phosphorus supply alters tuber composition, flower production, and mycorrhizal responsiveness of container-grown hybrid zantedeschia. Plant and Soil Journal. 283: 329-342. Interpretive Summary: Root colonization by arbuscular mycorrhizal fungi (AMF) can influence plant development and growth via changes in mineral uptake and resource partitioning; however, the effects of AMF on product quality of floral geophytes are unknown. Tubers of two hybrid calla lily (calla) cultivars (Zantedeschia ‘Pot of Gold’ [PG], ‘Majestic Red’ [MR]) were inoculated with AMF and grown at three different rates of phosphorus (P) supply to assess how inoculation alters aspects important to successful commercial production of this geophyte including, plant development, vegetative reproduction, flower production, and tuber quality. Tubers and flowers of calla responded differently to AMF inoculation. Differences in mycorrhizal responsiveness between cultivars were related to differences in P requirements for flower and tuber production and the influence of P supply on resource allocation to different reproductive strategies. For MR, benefits from AMF were primarily in terms of tuber yield and composition, and AMF effects on marketable flower production could potentially have negative impact on production strategies for growers. Inoculation of PG primarily influenced flower production and aspects of tuber quality that caused detectable enhancement of tuber yield and flowering in the second growing cycle following inoculation. Understanding how geophyte responsiveness to AMF is linked to patterns of resource allocation will aid in developing crop-specific inoculation strategies that are targeted towards enhancing productivity and quality of different end-products (e.g. bulbs, cut flowers, potted flowers). Technical Abstract: wo hybrid calla lily (calla) cultivars (Zantedeschia ‘Pot of Gold’ [PG], ‘Majestic Red’ [MR]) were inoculated with the arbuscular mycorrhizal fungus (AMF), Glomus intraradices, or not, and grown at three different rates of phosphorus (P) supply to assess the effects of AMF on plant development, flowering, and tuber biomass and composition over two growing cycles (2002, 2003). Tubers and flowers of calla responded differently to AMF inoculation. Differences in mycorrhizal responsiveness between cultivars were related to differences in P requirements for flower and tuber production and the influence of P supply on resource allocation to different reproductive strategies. Inoculation increased shoot and tuber production and promoted early flowering, but only increased the number of flowers per plant in 2003. High P supply also increased tuber biomass, but decreased the number of flowers per plant in 2002. Plants grown at a moderate P-rate, produced the most flowers in 2003. For MR, benefits from AMF were primarily in terms of tuber yield and composition, and AMF effects on marketable flower production could potentially have negative impact on production strategies for growers. Inoculation of PG primarily influenced flower production and aspects of tuber quality that caused detectable enhancement of tuber yield and flowering in the second growing cycle following inoculation (2003). The results of this study show that the responses of calla to AMF are partially a function of how nutrient supply alters resource allocation to sexual and vegetative reproduction. Whether AMF-induced changes in resource allocation to flowering and tubers significantly alters commercial productivity and quality of calla depends on the crop production goals (e.g. tubers, cut flowers, or potted plants). |
