The mycorrhizal status, root anatomy, and phenology of plants in a sugar maple forest

Abstract

The phenology, root anatomy, and mycorrhizal colonization of vascular plant species occurring in a hardwood forest site were studied. Sugar maple (Acer saccharum), the dominant tree, ash (Fraxinus americana), another important tree, and the most abundant herbaceous plants were examined periodically. Most of the herbaceous species present were highly colonized by vesicular–arbuscular mycorrhizae (VAM), but some consistently had low levels of VAM, or were nonmycorrhizal, and several had orchid mycorrhizae. Most trees were associated with VAM, although several ectomycorrhizal species occurred in low numbers. Herbaceous plants could be divided into four phenological categories of shoot activity, spring, spring–summer, summer, and fall, but many species had periods of root growth that did not parallel their aboveground activity. Almost all species that produced new roots in summer were well colonized by VAM, while those active mainly in late fall or early spring tended to be nonmycorrhizal. Roots of the woodland plants typically had a well-developed exodermis and also tended to be long-lived and coarse. Possible relationships among these root system characteristics, phenological categories, and levels of mycorrhizal colonization of woodland plants are discussed.

Some Mediterranean plant species (Lavandula spp. and Thymus satureioides) act as potential ‘plant nurses’ for the early growth of Cupressus atlantica

“…From the present work, it appears that the soil borne spores were not involved in this MSI enhancement. This result agrees with previous studies in which it has been attested that the AM mycelia network is the main source of inoculum in semiarid and arid ecosystems (Brundrett and Kendrick 1991;Bashan et al 2000). Table 6.…”

A test of mycorrhizal benefit in an early successional plant community

“…At present we do not know at what time infection becomes established in the plants studied here. Moreover, we were only able to take one mycorrhizal sample at the end of the season and a number of authors have demonstrated seasonal changes (Gay et al, 1982;Brundrett & Kendrick, 1988). The timing of infection and its relevance to soil P could be important and we are currently examining mycorrhizal infection and soil phosphorus levels in a ruderal community at regular intervals, in order to answer these questions.…”

Diversity and classification of mycorrhizal associations

“…Old dead roots are an important source of inoculum for glomeromycete fungi which can survive as endophytes in living roots for up to 10 years after arbuscules have collapsed, presumably functioning as inoculum reservoirs for subsequent generations of roots (Brundrett & Kendrick, 1988). These fungi also have a necrotrophic phase when host roots die, providing the fungus with first access to nutrients that can be transferred to hyphae in other plants (Eason, Newman & Chuba, 1991).…”