Articles
IN VITRO METHODOLOGY FOR INCREASING SALT TOLERANCE IN CROP PLANTS
Article number
336_8
Pages
69 – 78
Language
Abstract
Cell and tissue culture techniques, together with conventional breeding and genetic engineering, have been considered as the three main potential genetic approaches for the development of plants with increased tolerance to environmental stresses in general and for salt stress in particular.
The successful selection of mutant cell lines from cultured cells and the regeneration of whole plants from such cells have stimulated many attempts, most of them during the 1980’s, to apply the in vitro techniques for the development of salt-tolerant plants.
The cell culture approach has been proved effective in obtaining salt-tolerant cell lines in many plant species.
In almost all of the experiments the salt tolerance of the cells was found to be stable during mitotic divisions in salt-free media.
Unfortunately, although salt-tolerant lines are easily selected for, and whole plants were regenerated in about half of the experiments, there have been only a few cases where salt tolerance of the regenerants was determined or its sexual inheritance was verified.
A significant proportion of the regenerants have been defective in their development and/or fertility, and from those that were determined, some were found to be salt sensitive.
The main causes mentioned in the literature as being responsible for the limited success of the in vitro approach include: a) lack of correlation between the mechanisms of tolerance operating in cultured cells and those of the whole plant; b) lack of distinction between adapted cells and true mutants; c) multigenicity of salt tolerance; and d) lack, or loss during selection, of regeneration capacity.
The need for a better understanding of the physiological and genetic mechanisms of salt tolerance in cultured cells and their relationship to salt tolerance of the whole plants, as well as reasons for a renewed optimism in the in vitro approach are discussed.
The successful selection of mutant cell lines from cultured cells and the regeneration of whole plants from such cells have stimulated many attempts, most of them during the 1980’s, to apply the in vitro techniques for the development of salt-tolerant plants.
The cell culture approach has been proved effective in obtaining salt-tolerant cell lines in many plant species.
In almost all of the experiments the salt tolerance of the cells was found to be stable during mitotic divisions in salt-free media.
Unfortunately, although salt-tolerant lines are easily selected for, and whole plants were regenerated in about half of the experiments, there have been only a few cases where salt tolerance of the regenerants was determined or its sexual inheritance was verified.
A significant proportion of the regenerants have been defective in their development and/or fertility, and from those that were determined, some were found to be salt sensitive.
The main causes mentioned in the literature as being responsible for the limited success of the in vitro approach include: a) lack of correlation between the mechanisms of tolerance operating in cultured cells and those of the whole plant; b) lack of distinction between adapted cells and true mutants; c) multigenicity of salt tolerance; and d) lack, or loss during selection, of regeneration capacity.
The need for a better understanding of the physiological and genetic mechanisms of salt tolerance in cultured cells and their relationship to salt tolerance of the whole plants, as well as reasons for a renewed optimism in the in vitro approach are discussed.
Authors
M. Tal
Keywords
Cell culture, callus, selection, regeneration, cross resistance
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