Contrasting physiological responses to high salinity between two varieties of corn 'Lluteño' (salt tolerant) and 'Jubilee' (salt sensitive)

Libertad Carrasco-Rios1*, Carla Rojas1, and Manuel Pinto2
‘Lluteño’ is the only one corn capable to prosper in the Valley of Lluta under saline conditions (EC = 9.1 dS m-1). This cultivar has been little studied and there is no current information about its growth and about the possible mechanisms involved in its tolerance to salts. The aim of this research was to compare the growth of young plants of corn (Zea mays L.) ‘Lluteño’ to that of the bred ‘Jubilee’, both grown under different salt concentrations, to characterize the absorption and distribution of Na+ and other nutrients in the plant and to evaluate the effect of the saline conditions in the osmotic adjustment in both cultivars. The plants of 21 d old were subjected for 15 d to two saline treatments: 50 and 100 mM NaCl. The accumulation of DM was reduced from 5.12 to 1.80 g plant-1 in ‘Jubilee’ and 5.53 to 4.12 g plant-1 in ‘Lluteño’ (P ≤ 0.05). ‘Lluteño’ showed to be more tolerant to salt stress that ‘Jubilee’ by greatest accumulation of biomass under saline conditions, it was associated with a lower accumulation of Na+, steadiness of K+ and Ca2+ content and accumulation of osmolytes in leaves. The latter affecting positively the maintenance of relative water content and the osmotic adjustment of this cultivar in the leaves.
Keywords: Ion content, osmotic adjustment, salt stress, Zea mays.
1Universidad de Tarapacá, Facultad de Ciencias, Velásquez 1775, Arica, Chile. *Corresponding author (lcarrasc@uta.cl).2Instituto de Investigaciones Agropecuarias INIA, Santa Rosa 11610, La Pintana, Santiago, Chile