Date of Award

1997

Degree Type

Thesis

Degree Name

Bachelor of Science Honours

Faculty

Faculty of Science, Technology and Engineering

First Advisor

Dr Ian Bennett

Abstract

Increasing land degradation is recognised as an immediate worldwide threat. Human induced soil salinity is probably the major cause of land abandonment, through its adverse effects on plant growth. Salinity is a major focus of environmental researchers because it is recognised that counter-strategies can potentially reclaim both artificially degraded lands and intrinsically saline areas. Currently, strategies to combat salinity require that land use is changed, since restoration to a past use is usually economically impractical or impossible. Biological strategies show most promise. Revegetation of degraded soils with hardy plant species has met with considerable success, and shows promise for the future, given the vast, and as yet largely unknown, resources in plant genetic diversity. This diversity also gives rise to the need for testing of specific tolerances to soil salinity and associated soil conditions, such as waterlogging, to expedite revegetation programs. Growth of the introduced grass Agropyron elongatum, known for its tolerance to stress, was examined in a glasshouse at a range of salinities, in waterlogged conditions and in high soil pH, conditions often found on some minesites in the southwest of Australia. An indigenous grass Danthonia caespitosa and an indigenous daisy Podolepis gracilis were similarly examined. These trials were undertaken in order to determine any potential usefulness in minesite revegetation, and to compare a known halophyte with the tolerances of previously untested Australian species. A. elongatum was found to decrease in growth, but tolerate salt concentrations to 400mM, and to be unaffected by waterlogging. Both Australian species were found to be at least as tolerant of salt as A. elongatum, but to be sensitive to hypoxia caused through waterlogging. Both grasses showed apparent growth stimulation at low salt concentrations, though this is not in accordance with past studies on monocotyledonous plants.

Included in

Plant Biology Commons

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