Leaf Water Potential and Relative Water Content Variation in Creeping Bentgrass Clones

Abstract

Creeping bentgrass (Agrostis palustris Huds.) often requires daily irrigation and syringing to persist in turf areas in warmer environments with high evapotranspiration rates. Turfgrass performance could be enhanced if turgor maintenance under decreasing soil moisture levels could be incorporated into new bentgrass cultivars. The objectives of this study were to determine: (i) if genetic variation in leaf water potential (LWP) existed among creeping bentgrass clones under declining soil moisture, (ii) if LWP was associated with maintenance of growth under declining soil moisture levels, and (iii) if genotypic variation existed in water‐relation characteristics, including components of LWP, as determined by a hydraulic press. The LWP was measured on four field‐grown creeping bentgrass clones twice per day with a hydraulic press. Leaf water potential and soil moisture levels were determined in a growth room study on five creeping bentgrass clones grown in pots, 17 by 13 cm, during a 17‐d period. Waterrelation characteristics were determined on five creeping bentgrass clones grown in a greenhouse using a hydraulic press. Genetic variation existed among clones in LWP in both field and growth room studies. The most negative LWP was not associated with the greatest leaf firing or decrease in leaf extension. The relative water content at zero turgor represented a substantial difference in the degree of hydration at zero turgor. This study illustrated that genetic variation exists for LWP and relative water content in creeping bentgrass.