Silicon mitigates nutritional stress in quinoa (Chenopodium quinoa Willd.).

Nutritional deficiency is common in several regions of quinoa cultivation. Silicon (Si) can attenuate the stress caused by nutritional deficiency, but studies on the effects of Si supply on quinoa plants are still scarce. Given this scenario, our objective was to evaluate the symptoms in terms of tissue, physiological and nutritional effects of quinoa plants submitted to nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) deficiencies under Si presence. The experiment consisted of a factorial scheme 6 × 2, using a complete solution (CS), -N, -P, -K, -Ca, -Mg combined with absence and presence of Si (1.5 mmol L-1). Symptomatic, physiological, nutritional and evaluation vegetative were performed in quinoa crop. The deficiencies of N, P, K, Ca and Mg in quinoa cultivation caused visual symptoms characteristic of the deficiency caused by respective nutrients, hence decreasing the plant dry mass. However, Si supply attenuated the deficiency effects by preserving the photosynthetic apparatus, increasing the chlorophyll production, increasing the membrane integrity, and decreasing the electrolyte leakage. Thus, the Si supply attenuated the visual effects provided by deficiency of all nutrients, but stood out for N and Ca, because it reflected in a higher dry mass production. This occurred because, the Si promoted higher synthesis and protection of chlorophylls, and lower electrolyte leakage under Ca restriction, as well as decreased electrolyte leakage under N restriction.

Efecto del consumo del extracto de quinua en anemia ferropénica inducida en ratones / Effect of quinoa extract consumption on iron deficiency-induced anemia in mice

RESUMEN Objetivos Determinar efecto del consumo del extracto de quinua en anemia ferropénica inducida, en ratones. Material y Métodos Se utilizaron treinta ratones albinos M. musculus de la cepa Bal-b/c, machos de peso promedio 24±32,7 g. Se formó tres grupos de diez ratones cada uno: a) grupo control negativo hierro suficiente(HS),recibió 40g/d de alimento balanceado durante siete semanas; b)grupo control positivo hierro deficiente (HD), recibió 40g/d de dieta ferropénica durante siete semanas; y, c) grupo experimental hierro defi-ciente(HD), recibió 40g/d de dieta ferropénica durante siete semanas y a partir de la semana cinco se agregó 20g/d de extracto de quinua(EQ). Se midió el nivel de hemoglobina. Resultados Al finalizar el tratamiento, se observó diferencia significativa en los niveles de hemoglobina entre los grupos control positivo (8,9±1,1g/dL) HD y experimental (11,4±0,5 g/dL.) HD+EQ (t student, p<0,05). No se encontró diferencia significativa en los niveles de hemoglobina, al término del periodo de inducción entre los grupos control positivo (9,1±1,1) HD y experimental (9,3±0,7) HD (t student, p>0,05). Conclusiones En condiciones experimentales, la quinua presenta efecto antianémico, sustentado en los resultados de los niveles de hemoglobina.(AU)

ABSTRACT Objectives To determine the effect of quinoa extract consumption on iron deficiency-induced anemia in mice. Materials and Methods Thirty male M. musculus albino mice of the Balb/c strain, with an average weight of 24±32.7 g, were used. Three groups of ten mice each were formed: 1) a negative control group of iron-sufficient (IS) mice that received 40g/d of balanced feed for 7 weeks; 2) a positive control group of iron-deficient (ID) mice that received 40g/d of feed rich in iron for 7 weeks; and 3) an experimental group of ID mice that received 40 g/d of feed rich in iron for 7 weeks and 20 g/d of quinoa extract (QE) from week 5. Hemoglobin levels were measured. Results At the end of the treatment, a significant difference was found in hemoglobin levels between the positive (ID mice: 8.9±1.1 g/dL) and experimental (ID+QU mice: 11.4±0.5 g/dL) groups (student's t, p<0.05). No significant difference was found in hemoglobin levels at the end of the induction period between the positive (IS mice: 9.1±1.1) and experimental (ID mice: 9.3±0.7) groups (student's t, p>0.05). Conclusions Under experimental conditions, quinoa has an antianemic effect based on the results of hemoglobin levels.(AU)

Low-temperature effect on enzyme activities involved in sucrose-starch partitioning in salt-stressed and salt-acclimated cotyledons of quinoa (Chenopodium quinoa Willd.) seedlings.

The effect of low temperature on growth, sucrose-starch partitioning and related enzymes in salt-stressed and salt-acclimated cotyledons of quinoa (Chenopodium quinoa Willd.) was studied. The growth of cotyledons and growing axes in seedlings grown at 25/20 degrees C (light/dark) and shifted to 5/5 degrees C was lower than in those only growing at 25/20 degrees C (unstressed). However, there were no significant differences between low-temperature control and salt-treated seedlings. The higher activities of sucrose phosphate synthase (SPS, EC 2.4.1.14) and soluble acid invertase (acid INV, EC 3.2.1.25) were observed in salt-stressed cotyledons; however, the highest acid INV activity was observed in unstressed cotyledons. ADP-glucose pyrophosphorylase (ADP-GPPase, EC 2.7.7.27) was higher in unstressed cotyledons than in stressed ones. However, between 0 and 4days the highest value was observed in salt-stressed cotyledons. The lowest value of ADP-GPPase was observed in salt-acclimated cotyledons. Low temperature also affected sucrose synthase (SuSy, EC 2.4.1.13) activity in salt-treated cotyledons. Sucrose and glucose were higher in salt-stressed cotyledons, but fructose was essentially higher in low-temperature control. Starch was higher in low-temperature control; however, the highest content was observed at 0day in salt-acclimated cotyledons. Results demonstrated that low temperature induces different responses on sucrose-starch partitioning in salt-stressed and salt-acclimated cotyledons. Data also suggest that in salt-treated cotyledons source-sink relations (SSR) are changed in order to supply soluble sugars and proline for the osmotic adjustment. Relationships between starch formation and SuSy activity are also discussed.