Physiological Responses to Salt Stress at the Seedling Stage in Wild ( Griff.) and Cultivated ( L.) Rice.

Domesticated rice L. is a major staple food worldwide, and the cereal most sensitive to salinity. It originated from the wild ancestor Griff., which was reported to possess superior salinity tolerance. Here, we examined the morpho-physiological responses to salinity stress (80 mM NaCl for 7 days) in seedlings of an accession and two Italian genotypes, Baldo (mildly tolerant) and Vialone Nano (sensitive). Under salt treatment, showed the highest percentage of plants with no to moderate stress symptoms, displaying an unchanged shoot/root biomass ratio, the highest Na accumulation in roots, the lowest root and leaf Na/K ratio, and highest leaf relative water content, leading to a better preservation of the plant architecture, ion homeostasis, and water status. Moreover, preserved the overall leaf carbon to nitrogen balance and photosynthetic apparatus integrity. Conversely, Vialone Nano showed the lowest percentage of plants surviving after treatment, and displayed a higher reduction in the growth of shoots rather than roots, with leaves compromised in water and ionic balance, negatively affecting the photosynthetic performance (lowest performance index by JIP-test) and apparatus integrity. Baldo showed intermediate salt tolerance. Being interfertile with , it resulted a good candidate for pre-breeding towards salt-tolerant lines.