Skip to Main Content
Root hydraulic conductivity and xylem sap levels of zeatin riboside and abscisic acid in ectomycorrhizal Douglas fir seedlingsAuthor(s): Mark D. Coleman; Caroline S. Bledsoe; Barbara A. Smit
Source: New Phytol. (1990). 115, 275-284
Publication Series: Miscellaneous Publication
PDF: View PDF (624 KB)
DescriptionMechanistic hypotheses to explain mycorrhizal enhancement of root hydraulic conductivity (Lp) suggest that phosphorus (P) nutrition, plant growth substances and/or altered morphology may be responsible. Such ideas are based on work with VA (vesicular-arbuscular) mycorrhizas. Since VA mycorrhizas and ectomycorrhizas differ in many respects, they may alter host plant water uptake via different mechanisms. This paper examines Lp in various ectomycorrhizal associations while considering factors which are important to the VA mycorrhizal effect on Lp. Douglas fir Pseudotsuga menziesii (Mirb.) France] seedlings inoculated with the ectomycorrhizal fungi Laccaria bicolor (Maire) Orton and Hebeloma crustuliniforme (Bull. ex St. Amans) Quel. and non-inoculated seedlings infected naturally with Thelephora were grown under three low levels of P fertilization (1, 10 and 1OO µM P). Seedling morphology, tissue P levels, Lp and plant growth substance levels in xylem sap were measured after nine months growth. Increased tissue P and decreased root/shoot ratio correlated with increased Lp in each of the mycorrhizal treatments. When adjusted for the effect of these two factors, Lp of Laccaria and Hebeloma seedlings was still lower than the Thelephora seedlings. In a subsequent experiment, the Lp of seedlings with Hebeloma and Rhizopogon vinicolor Smith mycorrhizas was compared to the Lp of non-mycorrhizal seedlings,(grown at 100 µM P)and no differences were found among treatments. The lack of an ectomycorrhizal effect on Lp is quite different from the enhancement of host Lp by VA mycorrhizas. Zeatin riboside concentrations of Thelephora- and Hebeloma-infected seedlings were similar, yet higher than with Laccaria. There was no relationship between plant growth substances and Lp in ectomycorrhizal Douglas fir, despite lower zeatin riboside concentrations for Laccaria-inoculated plants.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationColeman, Mark D.; Bledsoe, Caroline S.; Smit, Barbara A. 1990. Root hydraulic conductivity and xylem sap levels of zeatin riboside and abscisic acid in ectomycorrhizal Douglas fir seedlings. New Phytol. (1990). 115, 275-284
KeywordsAbscisic acid, zeatin riboside, diurnal root conductance, ectomycorrhizas, phosphorus, root hydraulic conductivity
- Mycorrhizas on nursery and field seedlings of Quercus garryana
- Ectomycorrhizal inoculation of containerized Western conifer seedlings.
- Native mycorrhizal fungi replace introduced fungal species on Virginia pine and American chestnut planted on reclaimed mine sites of Ohio
XML: View XML