Date of Award

1995

Degree Type

Thesis

Degree Name

Bachelor of Science Honours

Faculty

Faculty of Science, Technology and Engineering

First Advisor

Dr Ian Bennett

Abstract

Each year approximately 20 million hectares of land become affected by increasing salinity. Salt tolerant plants are being used to rehabilitate salt affected areas. Plants use a variety of mechanisms to adapt to salt in their environments. Glycophytes tolerate low to moderate levels of salt while halophytes can tolerate very high salt levels. Many basic physiological attributes have been suggested as important components of a salt tolerant phenotype. These include, influx and/or efflux of ions across plasma membrane and the tonoplast, modification of membrane composition and synthesis of compatible solutes such as soluble carbohydrates, glycine betaines and proline. The project aimed to determine if proline could be used as an indicator for salt tolerance. To do this, experiments were set up in the glasshouse and in tissue culture to investigate the response to salt of whole plant, plant tissues and cells. The accumulation of proline, fresh weight, dry weight and water content were determined for A. nummularia, A. slipitata and F. irregularis. Shoot cultures of two clones of A. nummularia (ANU 001 and 101), A. stipilata (AST 001 and 002) and F. irregularis (FAN 001 and 102) and three clones of A. nummularia (ANU 001, 301 and 302) callus were grown on media containing different levels of salt in vitro. Three clones of A. nummularia (ANU 001, 301 and 302) and F. irregularis (FRAN 001, 102 and 203) were grown various levels of salt in a glasshouse. The proline concentration and productivity was different for all species' shoot cultures and there were differences between clones of A. nummularia and F. irregularis. The proline concentration of callus cultures increased with increasing salt, while the fresh weight decreased but there was no difference between clones. In the glasshouse, the clones of A. nummularia were not significantly different in proline concentration but accumulated high proline at control and high levels of salt. F. irregularis clones responded in a similar way. Further investigation is required to determine how this may reflect variation in salt tolerance.

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