Inoculation with Vesicular-Arbuscular Mycorrhizal Fungi and Rhizobacteria Alters Nutrient Allocation and Flowering of Harlequin Flower

Abstract

We assessed whether addition of arbuscular mycorrhizal fungus (AMF) inoculum or rhizosphere organisms from AMF inoculum alters aspects of flowering, corm production, or corm quality of harlequin flower (Sparaxis tricolor) for two growth cycles after inoculation. Using pasteurized and nonpasteurized growth medium, plants were inoculated with either inoculum of the AMF, Glomus intraradices, or washings of the inoculum containing rhizobacteria. Shoots of plants inoculated with AMF emerged 2 days earlier than shoots on noninoculated plants or plants inoculated with inoculum washings. Flowers on AMF-inoculated plants opened 7-8 days earlier and plants produced more flowers per plant and per inflorescence than noninoculated plants. AMF-inoculated plants partitioned a higher proportion of biomass to cormel production than to daughter corms and had higher concentration and contents of zinc, sulfur, nitrogen, amino acids, and carbohydrates than corms from noninoculated plants. The rhizosphere organisms associated with the AMF inoculum influenced several measures of plant development, growth, and corm production suggesting that there are organisms associated with our AMF inoculum that have beneficial effects on the growth and productivity of harlequin flower. While inoculation with AMF can promote shoot emergence, leaf production, and flower production of harlequin flower, inoculation also alters aspects of biomass partitioning and corm composition that play an important role in the production of this crop for corms and cormels.