The Effect of VA Mycorrhizal Infection and Phosphorus Status on Sunflower Hydraulic and Stomatal Properties

摘要: ABSTRACTKoide, R. 1985. The effect of VA mycorrhizal infection and phosphorus status on sunflower hydraulicand stomatal properties.—J. exp. Bot. 36: 1087-1098.Mycorrhizal (M) non-mycorrhizal (NM) plants were grown in a soil low phosphorusavailability (with without amendment) moderate (without amendment). Using the Ohm's law analogy measured leaf waterpotentials, stem water potentials, transpiration rates, hydraulic resistances calculated for thewhole plant, leaf, below components. Mycorrhizal (as high as 89%) was shown tohave no intrinsic properties soil/plant system over wide range oftranspiration rates either when M NM equivalent root length compared.When availability, undergiven environmental conditions same plants, andtranspiration rates. When values ofhydraulic resistance lower than under given sets environmentalconditions. These differences not due to difference theintrinsic plants. evident because stomatalresistances higher resistancevaried inversely with rate. significantly greater werecompared lesser length, givenenvironmental much length. This waslargely between large small notbecause elevated exhibited by plantswere attributed an enhanced status. Short term amendments made tophosphorus-deficient improved transpiration; similar andNM before became phosphorus-deficient, phosphorus-amended NMplants had data are discussed relation other reports ofmycorrhizal influence resistances. Possible mechanisms ofinfection also briefly discussed.Key words—Hydraulic resistance, mycorrhizas.Correspondence to: Department Biological Sciences, Stanford University, Stanford, CA 94305, U.S.A.