The effect of mycorrhizal fungi on the vegetative growth and sexual reproductive potential of purple loosestrife
Purple loosestrife is a perennial with proficient vegetative growth and sexual reproduction and is referred to as invasive. One factor shown to increase plant growth and reproduction is an association with arbuscular mycorrhizal fungi (AMF). Purple loosestrife forms such a symbiotic association, but there is no evidence that this plant is dependent on AMF. Vegetative growth and sexual reproductive potential of purple loosestrife was investigated using the AMF, 'Glomus aggregatum'. Four hypotheses were tested: AMF colonizes each floral morph, AMF increases vegetative growth, AMF increases sexual reproductive potential and no morph-specific differences exist. Two treatments (non-mycorrhizal and mycorrhizal) and three floral morphs (Long, Mid, Short) were randomized and analyzed using Factorial Analyses of Variance. Our results indicated AMF colonized all floral morphs, decreased biomass, did not influence flower production, and increased pollen production. Mycorrhizal colonization also influenced morphology by changing the distribution of lateral inflorescence buds, flower distribution within an inflorescence and shoot biomass allocation. This study suggests vegetative growth and sexual reproductive characters in purple loosestrife were influenced by the presence of mycorrhizal fungi. Further study is required to determine the implications of these morphological changes on purple loosestrife performance.