Author
|
Submitted to: International Conference on Mycorrhizae Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 7/8/2001 Publication Date: 7/8/2001 Citation: Page 1-23 Interpretive Summary: . Technical Abstract: The importance of arbuscular mycorrhizal (AM) symbiosis in perennial cropping systems is largely unknown. Grapevines (Vitis spp.) may be particularly dependent on mycorrhizal fungi, owing to their low root densities in soil. An examination of 70 commercial vineyards in Oregon and Washington has shown grape roots to be extensively colonized by AM fungi. Mean colonization of fine roots by AM fungi at veraison was 69% and 73% in Oregon and Washington vineyards, respectively. Arbuscular colonization was significantly greater in Oregon vineyards, averaging 48% at veraison in 1999, versus 19% in Washington vineyards at veraison in 2000. Arbuscular colonization of roots in Oregon vineyards was correlated most strongly to soil pH. The diversity of AM fungi in grape roots from 7 Oregon vineyards was assessed using amplified and cloned 18s ribosomal gene sequences. We have identified 15 potential AM-fungus species from grape roots with an average richness of 8 species per vineyard. However, 4 Glomus species dominate our root samples, representing 85% of the cloned products. Two of the four dominant species are G. intraradices and G. mosseae. A study of the spatial and temporal dynamics of mycorrhizae in a mature V. vinifera vineyard showed that arbuscular colonization of fine roots increased prior to bud break, continued to rise until veraison, dipped slightly, and increased again after harvest. Arbuscular colonization was related to known carbon allocation patterns within vines and to the timing of nutrient uptake from soil. AM fungi play a major role in real-world, grapevine production systems. |
