Anatomical and Physiological Responses of Four Quinoa Cultivars to Salinity at Seedling Stage

Abstract

Objectives: Salinity is one of the most important environmental stress factors that limits both seed germination and seedling develop. Seedling stage is the most susceptible stage of plants to salt stress. The aim of this work is to study the effect of salt stress on anatomical and physiological features of cotyledons and roots of the seedlings of four quinoa cultivars (Witulla, Wariponcho, Pasankalla and CICA). Methods/ Statistical Analysis: Seed germination and seedling growth was carried out under 0 and 200 mM NaCl during 10 days. Root length and diameter, and root proton extrusion were measured. Soluble sugars and proline concentrations were determined in both cotyledons and roots. Anatomical attributes of cotyledons (adaxial and abaxial stomatal area and density, palisade and spongy cell layers, palisade cell density) and roots (stele diameter and surface, metaxylem vessel diameter) were also analyzed. Findings: Salt stress caused physiological and anatomical changes in cotyledons and roots. Sucrose, glucose and fructose concentrations were more affected in cotyledons than in roots of salt-treated seedlings. Proline accumulation was more affected in roots. Saline stress affected differentially the anatomical attributes of quinoa cultivars. Application/Improvements: Quinoa seedlings when subjected to salt stress are able to develop a set of anatomical, physiological and biochemical adaptive mechanisms which seem to occur at different combinations among quinoa cultivars, but giving similar abilities to cope with the excess of salt and survive under extreme conditions.