Botany · Ch 9 — Plant Breeding
Arbuscular Mycorrhizae
Arbuscular Mycorrhizae
Arbuscular mycorrhizae (AM) form through a symbiotic association between certain phycomycetous (zygomycete-type) fungi and the roots of flowering plants. The fungal hyphae extend well beyond the root's own phosphate-depletion zone, giving the plant access to phosphate and other nutrients such as zinc and ammonium that would otherwise be out of reach (Figure 9.6). Beyond nutrient uptake, AM colonisation strengthens the plant's resistance to disease-causing organisms, unfavourable weather and drought and salt stress, and it helps ensure a more reliable water suppl …
What this figure shows. A comparative diagram with two root panels: the left panel shows a root with no AM colonization, where nutrient transfer happens only via root hairs and a phosphate-depletion zone (labelled with PO4 3- and NH4+ ions) forms close around the root, limiting uptake; the right panel shows an AM-colonised root, where a network of fungal hyphae (AMF) extends nutrient transfer for phosphate, zinc, ammonium and water well beyond the depletion zone. Surrounding labels list the benefits of colonisation: increased drought and salt tolerance, increased resistance to foliar pathogens, local resist …