Companion plants affect colonization of Myrica cerifera by vesicular–arbuscular mycorrhizal fungi

Abstract

The vesicular–arbuscular mycorrhizal (VAM) status of Myrica cerifera L. (wax myrtle) was investigated under greenhouse and field conditions. Myrica cerifera and Paspalum notatum Flügge (bahiagrass) were grown in inter- and intra-specific plant combinations with and without VAM fungi. Roots of field-collected M. cerifera were also examined for colonization by VAM fungi. Myrica cerifera became colonized by VAM fungi only in the presence of a VAM colonized grass plant; however, arbuscules were consistently lacking. VAM fungi had no effect on root or shoot growth of M. cerifera. When grown in the presence of P. notatum, shoot growth of M. cerifera was reduced, regardless of inoculation treatment. Colonization of field-collected M. cerifera roots ranged from 0 to 75%; however, nearly all samples lacked arbuscules. Unexpectedly, samples from wet sites had the highest colonization levels. Failure of M. cerifera to become colonized when grown without a VAM companion plant and the absence of arbuscules when M. cerifera became colonized in the presence of a VAM companion plant suggest that the VAM association of M. cerifera is nonfunctional. Key words: arbuscule, Glomus, interspecific, intraspecific, nonhost.