Date of Award

2000

Document Type

Thesis

Publisher

Edith Cowan University

Degree Name

Bachelor of Science Honours

Faculty

Faculty of Communications, Health and Science

First Supervisor

Dr Ian Bennett

Abstract

Increasing soil salinity has become a major problem worldwide. It has led to a reduction in the amount of arable land, has put at risk the supply of freshwater and threatens the existence of many natural habitats. The major increase in salinity has been attributed to human activities such as clearing of natural vegetation and large-scale irrigation programmes. The alleviation of this problem has focussed on changed management strategies. the most significant of which is the re-establishment of deep rooted plants in sail affected areas. This, however, is difficult because of the variation in salt tolerance of such plants and the problems created through nutrient deficiencies characteristic of such sites. This study investigated the role of ectomycorrhizal (ECM) associations in assisting eucalypts tolerate soil salt. The response of specific isolates of P. tinctorius Pers. To salinity in vitro was used to determine which may be the most effective when transferrred to saline soils. All isolates tested appeared to be at least tolerant or semi-tolerant to 150 mM NaCI. However, the different isolates produced different patterns of colony growth, making assessment of growth rates, and therefore salt tolerance, difficult. Inoculation of E. camaldulensis Dehnh. and E. diversicolor F. Muell. with spores of field collected Scleroderma species and Pisolithus tinctorius improved salt tolerance of E. camaldulensis but not E. diversicolor. Inoculation of E. diversicolor and E. camaldulensis seedlings and clones with P. tinctorius isolates used in in vitro studies, showed no significant growth response to salinity. This may be attributed to poor development of ECM structures within the root zone of these plants. Root and shoot proline content showed significant responses to both inoculation with ECM Fungi and salt treatment. These results did vary between experiments. Further research into the use of ECM to alleviate the problem of soil salinity is justified by this study. The development of new, and improvement of current techniques is discussed in light of these findings.

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