Morpho-physiological mechanisms of two different quinoa ecotypes to resist salt stress.

BACKGROUND: Quinoa (Chenopodium quinoa Willd.) is a facultative halophyte showing various mechanisms of salt resistance among different ecotype cultivars. This study aimed to determine salt resistance limits for a Peruvian sea level ecotype "Hualhuas" and a Bolivian salar ecotype "Real" and elucidate individual mechanisms conferring differences in salt resistance between these cultivars. The plants were grown in sandy soil and irrigated with various saline solutions concentrations (0, 100, 200, 300, 400, and 500 mM NaCl) under controlled conditions. RESULTS: High salinity treatment (500 mM NaCl) reduced the plant growth by 80% and 87% in Hualhuas and Real cultivars, respectively. EC50 (water salinity which reduces the maximum yield by 50%) was at a salinity of 300 mM NaCl for Hualhuas and between 100 and 200 mM NaCl for Real plants. Both cultivars were able to lower the osmotic potential of all organs due to substantial Na+ accumulation. However, Hualhuas plants exhibited distinctly lower Na+ contents and consequently a higher K+/Na+ ratio compared to Real plants, suggesting a more efficient control mechanism for Na+ loading and better K+ retention in Hualhuas plants. Net CO2 assimilation rates (Anet) were reduced, being only 22.4% and 36.2% of the control values in Hualhuas and Real, respectively, at the highest salt concentration. At this salinity level, Hualhuas plants showed lower stomatal conductance (gs) and transpiration rates (E), but higher photosynthetic water use efficiency (PWUE), indicative of an efficient control mechanism over the whole gas-exchange machinery. CONCLUSION: These results reveal that Hualhuas is a promising candidate in terms of salt resistance and biomass production compared to Real.

A Long Journey of CICA-17 Quinoa Variety to Salinity Conditions in Egypt: Mineral Concentration in the Seeds.

Quinoa may be a promising alternative solution for arid regions, and it is necessary to test yield and mineral accumulation in grains under different soil types. Field experiments with Chenopodium quinoa (cv. CICA-17) were performed in Egypt in non-saline (electrical conductivity, 1.9 dS m-1) and saline (20 dS m-1) soils. Thirty-four chemical elements were studied in these crops. Results show different yields and mineral accumulations in the grains. Potassium (K), P, Mg, Ca, Na, Mn, and Fe are the main elements occurring in the quinoa grains, but their concentrations change between both soil types. Besides, soil salinity induced changes in the mineral pattern distribution among the different grain organs. Sodium was detected in the pericarp but not in other tissues. Pericarp structure may be a shield to prevent sodium entry to the underlying tissues but not for chloride, increasing its content in saline conditions. Under saline conditions, yield decreased to near 47%, and grain sizes greater than 1.68 mm were unfavored. Quinoa may serve as a complementary crop in the marginal lands of Egypt. It has an excellent nutrition perspective due to its mineral content and has a high potential to adapt to semi-arid and arid environments.