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Abstract:
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The present study aimed to examine the effects of root colonization in tomato, Solanum lycopersicum L. cv. Moneymaker, by the arbuscular mycorrhizal (AM) fungus, Glomus intraradices Shenck and Smith, on alleviating salt stress. I postulated that AM symbiosis increases tomato plant performance to salt stress. Two greenhouse experiments were done according to a randomized factorial experimental design. The results showed a significantly higher level of AM root colonization that also occurred earlier in salt than non-salt treated plants. There were also positive interactions between root colonization levels and the alleviation of salt stress; these contributions resulted initially on higher root fresh mass (FM), later on shoot FM, and DM, and higher phosphorus and unchanged potassium concentrations in roots. The effects observed in salt-treated plants were significant when root colonization levels were significantly different than those observed in non-salt treated plants. This suggests a relationship between the level of root colonization and the alleviation of salt stress in plants. The attempt to use molecular techniques to detect early root colonization was quite successful in detecting the presence of G. intraradices in AM plants. However, it was not possible to detect the presence of the AM fungus as early as by classical root staining. This was observed presumably because sampling methods were different. In general, the results support the hypothesis that AM root colonization contributes to some extent to salt resistance of tomato plants. |
