Plant growth, phosphorus nutrition, and root morphological responses to arbuscular mycorrhizas, phosphorus fertilization, and intraspecific density

M. S. Schroeder, D. P. Janos

Research output: Contribution to journalArticle

62 Scopus citations

Abstract

We examined the effects of arbuscular mycorrhizas (AM), phosphorus fertilization, intraspecific density, and their interaction, on the growth, phosphorus uptake, and root morphology of three facultative mycotrophic crops (Capsicum annuum, Zea mays, and Cucurbita pepo). Plants were grown in pots with or without AM at three densities and four phosphorus availabilities for 10 weeks. AM colonization, plant weight, and shoot phosphorus concentration were measured at harvest. Root morphology was assessed for C. annuum and Z. mays. Phosphorus fertilization reduced but did not eliminate AM colonization of all species. AM, phosphorus, and density interacted significantly to modify growth of C. annuum and C. pepo such that increased density and phosphorus diminished beneficial effects of AM. Increased density reduced positive effects of AM on C. annuum and C. pepo shoot phosphorus concentrations. AM altered both Z. mays and C. annuum root morphology in ways that complemented potential phosphorus uptake by mycorrhizas, but increased density and phosphorus diminished these effects. We infer that increased density predominantly influenced plant responses by affecting whether or not carbon (photosynthate) or phosphorus limited plant growth. By exacerbating carbon limitation, high density reduced the benefit/cost ratio of mycorrhizas and minimized their effects.

Original languageEnglish (US)
Pages (from-to)203-216
Number of pages14
JournalMycorrhiza
Volume15
Issue number3
DOIs
StatePublished - May 1 2005

Keywords

  • Facultative mycotrophs
  • Intraspecific competition
  • Phosphorus-immobilizing soil
  • Row crops
  • Specific root length

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Plant Science

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