ARS | Publication request: FUNGAL ROOT ENDOPHYTES OF NATIVE GRASSES AND SHRUBS ON ARID RANGELANDS OF SOUTHWESTERN USA

Submitted to: Arid Soil Research And Rehabilitation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 23, 1996
Publication Date: N/A

Interpretive Summary: Symbiotic mycorrhizal fungi are known to assist most of the world's crop and native plants in taking up nutrients and water and are important for efficiency and plant survival. We have identified non-typical mycorrhizal- fungi in dominant shrubs and grasses in desert rangelands, where severe deterioration has occurred in the last 120 years. These symbiotic associations appear to have a major role in providing nutrients and water from scant and unpredictable supplies common to desert conditions. The maintainence of these beneficial fungal assocications are essential for rangeland managment and improvement for sustained stability and production.

Technical Abstract: This research was conducted to determine the nature and incidence of fungal root endophytes on fourwing saltbush, Atriplex canescens (Pursh) Nutt. Root cortex cells of fourwing saltbush in arid rangelands of the southwestern USA were analyzed and found to be regularly colonized with three types of endophytic fungi: septate, vesicular-arbuscular mycorrhizae e(VAM), and Chytridiomycetes. Septate fungi were 2.7 times more prevalent than VAM and formed intimate non-pathogenic associations characterized by inter- and intracellular hyphae, coils, microsclerotia, occasional labyrinthine or Hartig net' structures similar to those affiliated with ectendomycorrhizae. External hyphae formed intimate associations with soil and sand particles. Typically VAM were characterized by hyphae, vesicles and at times, coils. VAM were 2.2 times more prevalent than chytrids. Chytrids were rather common and expressed as resting and active sporangia found within root cortex cells. The widespread occurrence of these non- destructive fungal associations with plants implies they have an important role in plant survival in arid environments.