Date of Award:

5-2012

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Plants, Soils, and Climate

Committee Chair(s)

Roger Kjelgren (Committee Co-Chair), Paul G. Johnson (Committee Co-Chair)

Committee

Roger Kjelgren

Committee

Paul G. Johnson

Committee

Richard C. Beeson Jr.

Committee

Grant E. Cardon

Committee

Thomas A. Monaco

Abstract

Both salt and water deficit make it difficult for plants to uptake water from soil. Thus, plants under those conditions may respond and deal with them similarly. The overall objectives of this study were to 1) determine visual appearance and physiological responses, and mechanisms to deal with salt and water deficit of turfgrasses and woody species, and 2) determine the relationship between salt and water deficit tolerance ability in those species.

Five turfgrass entries, ‘Gazelle’ and ‘Matador’ tall fescue (TF), ‘Midnight’ Kentucky bluegrass (KBG), PI368233 (Tolerant KBG), and PI372742 (Susceptible KBG), and three woody species, bigtooth maple (xeric-non saline), bigleaf maple (mesic-non saline) and Eucalyptus (mesic-saline) were compared.

For the water deficit study, there was no irrigation in Chapter 2 while dry down treatment was based on daily water loss in Chapters 5 and 6. For the salinity study, NaCl and CaCl2 were used in turfgrasses at salt levels of 1, 6, 12, 18, and 30 dS m-1 (Chapter 3) and woody species at 1, 3, 6, 9, and 12 dS m-1 (Chapter 4).

Susceptible KBG was sensitive to salts but equally tolerant under water deficit as other turfgrasses. Salt tolerant turfgrasses could extract more water from soil and did not absorb salts into their tissues, while Susceptible KBG absorbed salt ions and transported to shoots, causing dead leaves. Under water deficit, leaves of all entries were dead at the same level of soil water content when there was no water for the plant to extract.

In woody species, Eucalyptus maintained acceptable visual appearance under salt stress while bigtooth maple showed this under water deficit. Bigleaf maple was sensitive to both drought and salinity.Eucalyptus had an ability to exclude salts at the roots which made it more tolerant to salt than bigtooth and bigleaf maple. Under water deficit, Eucalyptus and bigleaf maple maintained water uptake and grew normally until there was no water available to be extracted and they died. In contrast, bigtooth maple conserved water in tissues to maintain acceptable visual appearance but not growing over a drought period.

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This work made publicly available electronically on May 9, 2012.

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