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Turgor Potential and Osmotic Constituents of Kentucky Bluegrass Leaves Supplied with Four Levels of Potassium
Author(s) -
Carroll Mark J.,
Slaughter Leon H.,
Krouse John M.
Publication year - 1994
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1994.00021962008600060028x
Subject(s) - turgor pressure , potassium , osmolyte , poa pratensis , chemistry , sucrose , osmotic pressure , phosphorus , osmoregulation , nutrient , agronomy , horticulture , botany , zoology , poaceae , biology , salinity , food science , biochemistry , ecology , organic chemistry
Solute accumulation is one mechanism by which plants are able to sustain positive leaf turgor potentials (ψ t ). Potassium, the cation most often found in greatest concentration in Kentucky bluegrass ( Poa pratensis L.), can influence accumulation of solutes. A 2‐yr glasshouse study was conducted to determine the effect of K availability on accumulation of six osmotically active solutes and ψ 1 within leaves of Kentucky bluegrass. Four nutrient solutions containing 0, 10, 100, or 124 mg K L −1 were applied three times weekly to plants grown in silica sand. Small increases in K (0 to 10, or 100 to 124 mg L −1 ) had no effect on ψ t but increasing K from 0 or 10, to 100 or 124 mg L −1 increased leaf ψ t 0.19 to 0.35 MPa. Increasing K from 10 to 100 mg L −1 caused leaf osmotic potential (ψ Л ) to decline by 0.17 to 0.23 MPa. Potassium was the only measured osmotically active solute that could account for most of the decline in ψ Л . When the supply of K was increased from 10 to 100 mg L −1 , the resulting increase in leaf K concentration caused the calculated contribution of K alone to depress leaf ψ Л by 0.29 to 0.31 MPa. Conversely, the combined calculated osmotic contribution of Ca, Mg, glucose, fructose, and sucrose increased leaf ψ Л by 0.12 to 0.13 MPa when K was increased from 10 to 100 mg L −1 . The calculated osmotic contribution of all six osmolytes accounted for 46 to 60% of the measured ψ Л . Increasing Kentucky bluegrass K tissue concentration appears to have a small but positive influence in increasing leaf turgor.