[Physiological responses of Hordeum vulgare L. cv. Keys to sodium chloride in relation with ionic excess]
1992
Chorfi, A.
Soil salinity is a major obstacle to plant growth in arid and semi-arid regions. The effects of salinity are considered under three main headings: osmotic effects, effects on plant nutrition and ionic excess. This latter aspect forms the main focus of the dissertation. The dissertation comprises 5 main parts: A study of the effects of NaCl on the growth of Barley (Hordeum vulgare L. cv. Keys) with a view to determining the degree of tolerance or sensitivity of this cultivar. The study of the uptake and accumulation of Na+ and Cl- ions. This required the use of the radioisotopes 22Na and 36Cl to detect loci of concentration of these ions in the whole plant. The mechanism of Na+ and Cl- efflux in roots. Long distance transport and re-distribution of 22Na and 36Cl following foliar application. Evidence for foliar exudation corresponding to loss of Na+ and Cl- from above plant parts. It is concluded that Hordeum vulgare L. cv. Keys is salt tolerant. This is achieved by the operation of several different types of physiological process: selectivity between K+/Na+ in leaf blades, preferential accumulation of Na+ and Cl- in stems and leaf sheaths, efflux of Na+ from roots, long distance transport of absorbed ions and foliar exudation of ions.
显示更多 [+] 显示较少 [-]