A method to quantify active external hyphae of VAM fungi on root surfaces and in soil is described. Hyphae attached to roots or extracted from soil are incubated in a solution containing indonitrotetrazolium and NADH and counter-stained with trypan blue. The method allows for the assessment of growth VAM fungi in soil. Pot cultures of Paspalum notatum were inoculated with Clomus mosseae or G. intraradices and were grown in a glasshouse for 13 wk. Greater than 96% of the hyphae attached to roots were active from week 3 to 13. The proportion of active hyphae extracted from soil ranged from 0 to 32% during the 13 wk period, but increased dramatically between 6 and 9 wk. The production of active external hyphae lagged behind root colonization by several weeks. The importance of hyphal activity in relation to nutrient uptake and translocation by VAM fungi is discussed.
All Science Journal Classification (ASJC) codes
- Soil Science