[Study of tomato root system responses to NaCl [Lycopersicon spp.]] | Etude du systeme racinaire en presence de NaCl chez la tomate (Lycopersicon spp.)
2001
Kouki, K.
The cultivation of tomatoes (Lycopersicon esculentum Mill.) can be limited by salinity in arid and semi-arid regions. The aim of this research was to investigate the morphological and physiological responses of different Lycopersicon species to NaCl, with a view to understanding their roles in determining the salt tolerance of whole plants. Isolated roots, cultivated in vitro, and whole plants, cultivated in hydroponics, were used as experimental systems. Relative growth rate (RGR) of isolated roots was significantly reduced in Lycopersicon chilense (drought resistant) and Lycopersicon cheesmanii (salinity - resistant), moderately reduced in Lycopersicon esculentum (cultivated species) and showed little reduction in the L. esculentum mutant flacca (sensitive to osmotic stress). Two main mechanisms of osmo-regulation have been demonstrated in roots: an increase in the concentrations of selected sugars (fructose, glucose, sucrose) in L. chilense and L. esculentum and increases in cation (Na+, K+ concentrations in Lycopersicon pennellii. Results from both isolated roots and whole plants demonstrate that the tolerance of tomato plants to salinity is based upon both the degree of inherent root tolerance to NaCl and the rate at which the root system develops. Root culture could be used as rapid, efficacious test for evaluating these two features in breeding programmes for salt tolerance.
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