Compartive responses to salinity in wheat genotypes differing in salt tolerance 1-seeding growth and mineral relations

Caryopses of 2 Triticum estivum genotypes, differing in salt tolerance were grown hydroponically under natural environmental conditions [in the laboratory] with and without different concentrations of NaCl added to the growth medium. The effect of increasing NaCl levels on vegetative growth and mineral composition of shoot and root of the 2 cultivars has been studied. In general, 50 mM NaCl had no effect on the growth of shoot and root of both cultivars. NaCl at 100 mM significantly reduced fresh mass, dry mass and relative growth rate of shoot and root of Sakha 8 but only affected those of Giza 162 shoot, reduction was greater in Sakha 8. Salt treatment increased root/shoot, ratio in Giza 162 whereas it had no significant effect in Sakha 8. Shoot fresh mass/dry mass ratio was only decreased by high salt level in both cultivars. Increased salinity in the root medium significantly increased Na and Cl and decreased K levels in both shoot and root of Sakha 8 and Giza 162. At 100 mM NaCl, Sakha 8 shoot had greater Na concentration than that of Giza 162

Comparative responses to salinity in wheat genotypes differing in salt tolerance 2-cell permeability, osmotic potential and cytoplasmic viscosity

Caryopses of two Triticum estivum genotypes, differing in salt tolerance [Sakha 8, tolerant, Giza 162, sensitive], were hydroponically grown under natural environmental conditions [in the laboratory] in presence and absence of different concentrations of NaCl added to the growth medium. NaCl stress increased nonelectrolyte permeability of leaf sheath subepidermal cells in Giza 162 [sensitive], whereas no such effect of salt was found in Sakha 8 [tolerant]. Psi s of leaf sheath subepidermal cells of both cultivars was decreased with rising NaCl concentration in the external solution. At 100 mM NaCl, the decrease in psi s in Giza 162 was greater than that found in Sakha 8. Cytoplasmic viscosity of Giza 162 was decreased by NaCl addition to the growth solution, although viscosity was higher in Giza 162 than in Sakha 8 under control condition [O mM NaCl]. Cytoplasmic viscosity in Sakha 8, however, did not change by salt stress. The results confirmed and extended earlier data that cytoplasmic characteristics are different in wheat salt sensitive and tolerant genotypes, they may correlate with salt tolerance

Amelioration of salinity effect in salt sensitive wheat by choline chloride presoaking of caryopses

Caryopses of salt sensitive wheat cultivar were presoaked in 5 mM choline chloride and then subjected for 100 mM NaCl added to the 1/4-strength Hoagland solution for 21 days. The effect of salt stress in the presence and absence of choline was studied on the vegetative growth, mineral contents of shoot and root and cell permeability of leaf sheath subepidermal cells and root cortex cells. Choline presoaking of wheat caryopses alleviated the NaCl-induced growth reduction of shoot and root comparing with those received only salt treatment. Also, choline decreased cell permeability of shoot and root cells. NaCl stress increased root and shoot Na and Cl, and decreased K and Ca levels, whereas choline treatment decreased Na and Cl and increased K levels in relation to those that did not receive choline treatment. The results were discussed in terms of how choline induced salt tolerance in sensitive wheat cultivar under salt stress