Record ID No. |
1782 |
Author(s) |
Warren, J.M., Brooks, J.R., Meinzer, F.C., Eberhart, J.L , 2008 |
Affiliation |
US Forest Serv, Pacific NW Res Stn, Corvallis,OR 97331 USA |
Title |
Hydraulic redistribution of water from Pinus ponderosa trees to seedlings: evidence for an ectomycorrhizal pathway |
Source. Vol.(no):Page |
New Phytologist.178(2):382-394p |
Categories |
Ectomycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Organism |
n.a. |
Country |
United States |
Abstracts |
While there is strong evidence for hydraulic redistribution (HR) of soil water by
trees, it is not known if common mycorrhizal networks (CMN) can facilitate HR from mature trees
to seedlings under field conditions. Ponderosa pine (Pinus ponderosa) seedlings were planted into
root-excluding 61-mu m mesh barrier chambers buried in an old-growth pine forest. After 2 yr,
several mature trees were cut and water enriched in D2O and acid fuchsin dye was applied to the
stumps. Fine roots and mycorrhizal root tips of source trees became heavily dyed, indicating
reverse sap flow in root xylem transported water from stems throughout root systems to the root
hyphal mantle that interfaces with CMN. Within 3 d, D2O was found in mesh-chamber seedling
foliage > 1 m from source trees; after 3 wk, eight of 10 mesh-chamber seedling stem samples were
significantly enriched above background levels. Average mesh-chamber enrichment was 1.8x greater
than that for two seedlings for which the connections to CMN were broken by trenching before D2O
application. Even small amounts of water provided to mycorrhizas by HR may maintain hyphal
viability and facilitate nutrient uptake under drying conditions, which may provide an advantage
to seedlings hydraulically linked by CMN to large trees. |