Physiological causes for decreased productivity under high salinity in Boma, a tetraploid Chloris gayana cultivar

摘要: Rhodes grass (Chloris gayana Kunth) is widely cultivated in the semi-arid tropics and favoured for salt tolerance; nevertheless, productivity decreases significantly under saline conditions, especially tetraploid cultivars. The purpose of this work was to explore, cultivar Boma, physiological causes such decrease. Experiments were carried out vegetative plants greenhouse. At high salinity (200 mM NaCl), an early reduction leaf area expansion observed, and, later, decreased dry matter accumulation, suggesting that central effect a limitation growth. This evaluated 2 closely related Boma clones, exhibiting different degrees tolerance. Growth, ion accumulation excretion, sugars, proline concentrations measured range (0–200 NaCl). Differences between clones expressed only at salinity, but not associated with differences water potential or hydraulic conductance expanding region. all levels, proportion leaves higher clone which also had lower gland density Na excretion rates. Less efficient extrusion, oxidative stress, may be main cause senescence these clones.