Efficiency of boron application in an Oxisol cultivated with banana in the Central Amazon

In the Amazon region, there is no information on the fertilization of banana plants with boron (B). Besides this, the extractant (hot water) currently used to test B concentrations has many limitations. The aim of this work was to study the effect of B on the fruit yield and quality of banana plants of the Cavendish (AAA) sub-group, grown in dystrophic Yellow Latosol (Oxisol or Xanthic Ferralsol), in the Amazonas State, Brazil. The experimental design was completely randomized split plot in a 4 x 2 factorial scheme, composed of four B rates (0, 4, 8 and 12 kg ha-1) and two harvest cycles (sub-treatments), with four replicates. The B availability in the soil was determined by three extractants: Mehlich 3, hot water and KCl 1.0 mol L-1. The application of B influences the fruit yield, pulp/peel ratio, pulp resistance and B content in the leaves and fruits. The KCl 1.0 mol L-1 extractant was similar to the hot water in the evaluation of available B. To obtain maximum yield, it is necessary to apply 4.1 and 6.1 kg ha-1 of B in the first and second cycles, respectively.

Na Amazônia não existem informações sobre adubação com boro (B) na bananeira, além disso, o extrator água quente, que é atualmente o mais utilizado, apresenta inúmeras limitações. O objetivo deste trabalho foi estudar o efeito do B sobre a produção e qualidade dos frutos da bananeira do subgrupo Cavendish (AAA), cultivada em Latossolo Amarelo distrófico, no Estado do Amazonas, Brasil. O delineamento experimental utilizado foi o inteiramente casualizado em parcela subdividida em esquema fatorial 4 x 2, constituído por quatro doses de B (0, 4, 8 e 12 kg ha-1) e dois ciclos de colheita - sub-parcelas (primeiro e segundo ciclo), com quatro repetições. A disponibilidade de B no solo foi determinada pelos extratores Mehlich 3, água quente e KCl 1,0 mol L-1. A aplicação de B influenciou a produção, relação polpa e casca, resistência da polpa e o teor de B nas folhas e nos frutos. O extrator KCl 1,0 mol L-1 foi semelhante ao água quente na avaliação do B disponível. Para obtenção do máximo potencial de produção é necessário aplicar 4,1 e 6,1 kg ha-1 de B no primeiro e no segundo ciclo, respectivamente.

Alteration of the reproductive patterns in drosophila melanogaster by effects of high concentrations of boron on in vitro cultured medium / Alteración de los patrones reproductivos en drosophila melanogaster por efectos de altas concentraciones de boro en un medio de cultivo in vitro

The objective of this study was to evaluate the effects of boron (B) using as a biological model Drosophila malanogaster. Analizing specifically the responses over descendency to doses of 6,0 and 12 mg/L, comparing a control group which culture medium was prepared with water with boron concentrations of 0,6 mg/L, according to World Health Organization. The results show a significative alteration in the number of descendency from F1 to F3 and then a tendency to normalization in F4 and F5. Also a significant change in proportions between the males and females, with an acute effect on F1 and then a possible chronic effect from F2 to F5, increasing the proportion of females over males. This differences between genders are significant only until F4, on F5 these proportions are not significant. In F3 in doses of 12.0 mg/L of boron, it is observed a larger range of changes, altering the phenotypic expression, where the numbers of males which increase their size are significantly higher of those females who increase their size, 10 percent and 5,2 percent respectively. There is a tendency to normality in every pattern of study from the descendants of F4 and F5, above all the percentage of survival, possibly due action of steroid hormones of resistance to stress such as "ecdysone hormone".

El objetivo de este estudio fue evaluar el efecto del boro (B), usando como modelo biológico a Drosophila melanogaster. Específicamente analizar las respuestas sobre la descendencia a dosis de 6,0 y 12 mg/L y comparar con el grupo control cuya concentración de boro en el agua del medio de cultivo no supera los 0,6 mg/L, según los estándares de la Organización Mundial de la Salud. Los resultados muestran una alteración significativa en el número de la descendencia desde F1 a F3 y luego una tendencia a la normalización a partir de la F4 y F5. También hay un cambio significativo en las proporciones entre machos y hembras, con un efecto agudo en F1 y luego un posible efecto crónico desde F2 a F5, aumentando la proporción de hembras con respecto a los machos. Sin embargo estas diferencias entre sexos ya no son significativas solamente hasta F4. En F5 estas proporciones no son significativas. En F3 en dosis de 12 mg/L de boro, se observan los mayores cambios, alterando la expresión fenotípica, donde el número de machos que incrementan su tamaño, son significativamente más altos con respecto a las hembras que aumentan de tamaño. La tendencia a la normalidad en todos los patrones de estudio a partir de la descendencia F4 a F5, sobre todo en el porcentaje de sobreviva, posiblemente se deba a la acción de hormonas esteroidales de resistencia al estrés, tal como la hormona "Ecdysona".

Amelioration of NaCl stress in Pisum sativum Linn.

Activity of endogenous auxins and growth inhibitors, gibberellins and cytokinins was observed in the extracts of seedlings of Pisum sativum under NaCl stress. After 6 days of germination, when Pisum sativum seedlings were subjected to low concentration of NaCl (50 mM) or boron (10 ppm) increased the endogenous growth regulating substances. Higher concentration of NaCl (150 mM) decreased endogenous level of growth regulators, length of the root and shoot, and fresh and dry weights of seedlings, whereas boron increased the parameters except endogenous growth regulators. Mitotic index and some abnormalities were observed in the treated plants. SDS-PAGE banding pattern of Pisum sativum seedlings extracted in tris-glycine and tris-HCl showed that lower concentration of NaCl increased the number of protein bands, while the higher concentration decreased these protein bands. Combination of boron and NaCl (150 mM) caused an increase in total number of protein bands compared with the total number of bands recorded by using NaCl (150 mM) alone.