Date of Award:

5-2013

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Committee Chair(s)

Paul G. Johnson

Committee

Paul G. Johnson

Committee

Shaun Bushman

Committee

Joseph Robins

Abstract

Salinity is a significant stress for plants world-wide. In agriculture, salts reduce germination, overall growth, yield, and sometimes death in crop plants. Salinity similarly affects turfgrass in our urban landscapes. Kentucky bluegrass (Poa pratensis L.) is the most widely used cool-season grass in the northern part of the United States, including the cool-arid West, but generally is a salt sensitive species. The overall objectives of this study were to study the physiological responses of Kentucky bluegrass to salt stress and to evaluate the genetic similarity among the cultivars used in the research.

Four Kentucky bluegrass entries, two salt-tolerant and two salt-sensitive, were used in this research were exposed to four levels of salinity stress. Soil moisture sensors were used to measure soil salinity levels. Several measurements of plant health were used to evaluate stress responses including turf quality, stomatal conductance, water potential, and electrolyte leakage. Molecular methods were used to evaluate genetic diversity of the same Kentucky bluegrass accessions.

In general, turf quality, stomatal conductance, and water potential decreased while electrolyte leakage increased with the increase of salt concentration. Susceptible varieties Midnight and Baron showed greater changes in these measurements, indicating more sensitivity to salts than 768 and 603. The 6 dS m-1treatment had little effect on the salt-tolerant entries and had effect on the salt-susceptible accessions. Among the measurements used, turfgrass quality, water potential, and electrolyte leakage were the most accurate. In future studies to screen salt tolerant plants, electrolyte leakage and turf quality are recommended methods.

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