The need for salinity-tolerant turfgrasses is increasing because of increased use of effluent water for turfgrass irrigation. Greenhouse studies were conducted to determine the relative salt tolerance and salt tolerance mechanisms of `Challenger' Kentucky bluegrass (Poa pratensis), `Arid' tall fescue (Festuca arundinacea), `Fults' alkaligrass (Puccinellia distans.), and a saltgrass (Distichlis spicata) collection. Kentucky bluegrass and tall fescue were irrigated with saline solutions at 0.2,1.7, 4.8, or 9.9 dS/m, whereas alkaligrass and saltgrass were irrigated with saline solutions at 0.2, 28.1, 32.8, or 37.5 dS/m prepared using a mixture of NaCl and CaCl2. The salinity levels that caused 50% shoot growth reduction were 9.0, 10.4, 20.0, and 28.5 dS/m for Kentucky bluegrass, tall fescue, saltgrass, and alkaligrass, respectively. Concentrations of proline, a proposed cytoplasmic compatible solute, were 25.8, 30.4, 68.1, and 17.7 μmol/g shoot fw in Kentucky bluegrass, tall Fescue, alkaligrass, and saltgrass, respectively, at the highest salinity level imposed. Bicellular, salt-secreting glands were only observed by scanning electron microscopy on leaves of saltgrass, indicating salt secretion is one of the important salt tolerance mechanisms adopted by saltgrass. Ion contents (Na, Cl, and Ca) in both shoots and roots of all grasses increased with increasing salinity levels. However, alkaligrass maintained a much lower Na, Ca, and Cl contents in roots and shoots than other grasses, suggesting that ion exclusion is one of the major salt tolerance mechanisms in alkaligrass. Tall fescue did not appear to restrict the uptake and translocation of salt in shoot tissues, but maintained a higher K/Na ratio than all other grasses under saline conditions.
(140) Salt Tolerance Assessment of Kentucky Bluegrass Cultivars Selected for Drought Tolerance
