Cytokinin production by two ectomycorrhizal fungi in liquid culture

Fine roots and ectomycorrhizas as indicators of environmental change

“…Carbon source -sink relationships or functional balance of roots and shoots were reported as primary factors in continuous adjustments between root and shoot growth (Tingey et al, 1976), possibly acting through root to shoot signaling, including hormonal regulation of root proliferation. In this context, the effects of ozone-fumigation on the cytokinins (CK) of beech trees (Winwood et al, 2007) can be related to mycorrhiza-associated changes in cytokinin concentrations in the host plants (Kraigher et al, 1991(Kraigher et al, , 1993 and ozone-induced changes in fine root growth and ECM community structure (Grebenc & Kraigher, 2007a).The sensitivity to ozone has been reported to differ between species (for review see Bortier et al, 1999Bortier et al, , 2000aAndersen 2003), between different clones and populations (Ballach et al, 1992;Ottossen et al, 2003;Vanhatalo et al, 2003), experimental growth conditions, such as duration of the fumigation, light regime, irrigation, mineral nutrition and combination of different stress factors (McLaughlin & Downing, 1995;Roth & Fahey, 1998;Lö w et al, 2006; and between the age-related physiological differences within the same species (Matyssek et al, 2007). Ozone induced root growth reductions were found to alter the functioning of the rhizosphere organisms and to make them more susceptible to drought or nutrient deficiency (Woodbury et al, 1994).…”

Role of Cytokinins in Plant Growth Promotion by Rhizosphere Bacteria

“…A standard curve based upon the addition of specific quantities of cytokinins to the assay is used to quantify cytokinins present in samples. Since the first report of an anti-cytokinin antibody by Hacker et al (1970), antisera and monoclonal antibodies have been used to isolate and quantify endogenous cytokinins from a wide variety of plant tissues (Weiler, 1984;Hansen et al, 1988;Saavedra-Soto et al, 1988;Doumas et al, 1989) and microbial sources (Muller et al, 1988;Taller and Wong, 1989;Kraigher et al, 1991;Morris et al, 1991;Upadhyaya et al, 1991). As immunoassays have both high specificity and sensitivity with detection limits at the femtomole level, plant crude extracts can be used (Weiler and Ziegler, 1981;Weiler, 1984;Belding and Young, 1989;Young, 1989).…”

Ozone Stress and Ectomycorrhizal Root–Shoot Signaling

“…Carbon sourcesink relationships or functional balance of roots and shoots were reported as primary factors in continuous adjustments between root and shoot growth (Tingey et al 1996), possibly acting through root to shoot signaling, including hormonal regulation of root proliferation. In this context, the effects of ozone-fumigation on the cytokinins (CK) of beech trees (Winwood et al 2007) can be related to mycorrhizaassociated changes in cytokinin concentrations in the host plants (Kraigher et al 1991(Kraigher et al , 1993 and ozone-induced changes in fine root growth and ectomycorrhizal community structure . The role of cytokinins in stressrelated mycorrhiza-root-shoot signaling in ozone-fumigated beech trees and impacts of ozone fumigation on ectomycorrhizal root growth and community structure will be discussed.…”

“…Twelve different ectomycorrhizal fungal species were tested for cytokinin production in liquid culture (Kraigher et al 1991). All (Amanita muscaria, Laccaria bicolour, L. laccata, L. proxima, Lactarius rufus, Hebeloma crustulliniforme, H. subsaponaceum, Paxillus involutus, Pisolithus tinctorius, Rhizopogon vinicolor, Suillus luteus, Thelephora terrestris) secreted cytokinin into the medium (measured by RIA).…”