Combined effects of excess boron and salinity on root histology of Zea mays L. Amylacea from the Lluta valley (Arica, Chile)

Cell structure and alterations in tissue organization were analyzed for roots of Zea maysL. amylacea as a consequence of high salinity and boron (B) levels. Saline treatment concentrations were 100 mM NaCl (Low salinity, L) and 430 mM NaCl (High salinity, H). An excess of B was supplied as boric acid to obtain 20 (334 µM) and 40 (668 µM) mg B kg^–1 in the nutrient solution for 20 days. Our results complement other studies on the amylacea ecotype and confirm the high degree of tolerance to salinity and excess B shown by this variety. The application of B under no salt and low salinity conditions did not result in structure changes in root cortex cells nor the vascular cylinder. Under high salinity conditions amylacea root cells showed slight alterations, such as an increase in the number of rows of cells. These high salinity conditions did not result in thickness of the stele.