Gas Exchange, Root Morphology and Nutrients in Maize Plants Inoculated with Azospirillum brasilense Cultivated Under Two Water Conditions

HIGHLIGHTS Azospirillum brasilense stimulates root growth in maize under water deficit. Maize inoculated with A. brasilense shows greater photosynthesis under drought conditions. Under water deficit, maize plants inoculated with A. brasilense showed greater water use efficiency (WUE).

Abstract The objective of this study was to evaluate the gas exchange, root morphology and nutrient concentration in maize plants inoculated with A. brasilense under two water conditions. The experiments were carried out in a greenhouse, one under irrigation and the other under water deficit. The treatments consisted of four A. brasilense inoculants (control (without inoculation), Az1 (CMS 7 + 26), Az2 (CMS 11 + 26) and Az3 (CMS 26 +42). At the V6 plant stage, water stress was imposed on maize plants for 15 days. The phytotechnical characteristics, gas exchange, root morphology, root dry matter and macronutrient analysis were evaluated after 15 days of water deficit imposition. The water deficit caused a reduction in the development of maize plants. The presence of A. brasilense Az1 under the same condition yielded higher photosynthesis, carboxylation efficiency, water use efficiency, and greater soil exploration with increased length, surface area and root volume of plants. Inoculation by A. brasilense increased root system volume by an average of 40 and 47% under irrigation and water deficit, respectively, when compared to non-inoculated plants. The inoculant Az1 attenuated the deleterious effects caused by drought and yielded the best growth of the root system, resulting in the tolerance of maize plants to water deficit.

Valores de trihalometanos en agua de consumo de la provincia de Granada, España / Trihalomethane levels in drinking water in the province of Granada [Spain]

Objetivos: La cloración del agua da lugar a la formación desubproductos potencialmente dañinos para la salud, entre elloslos trihalometanos, que se han hallado elevados en algunaszonas de España. En este estudio se investigan los valoresde trihalometanos en el agua de consumo suministrada porvarios sistemas de abastecimiento de la provincia de Granada,en el área de actuación de la cohorte madres-hijos de laRed INMA (Infancia y Medio Ambiente).Métodos: Se analizaron 82 muestras de agua de consumoen dos campañas de muestreo en invierno y verano de 2006.Se determinó la concentración de cloroformo, bromodiclorometano,dibromoclorometano y bromoformo, siguiendo un procedimientooptimizado basado en cromatografía de gases yespectrometría de masas.Resultados: El rango de concentración de trihalometanos totalesse situó entre 0,14 y 18,75 g/l en la campaña de inviernoy entre 0,01 y 31,87 g/l en la de verano. El compuestomayoritario fue cloroformo. La concentración media de trihalometanosen agua de origen superficial y subterráneo fue de10,13 y 1,41 g/l, respectivamente.Conclusiones: Los valores de trihalometanos encontradosson muy inferiores a la concentración máxima admisible (100g/l) establecida por la Unión Europea para estos compuestos.Estos valores varían significativamente según el origendel agua, con mayores concentraciones en áreas urbana ysemiurbana, donde el agua es mayoritariamente de origen superficial.La presencia de trihalometanos en la zona es menora la descrita en otras regiones españolas(AU)

Objectives: Drinking water chlorination generates potentiallyharmful by-products, such as trihalomethanes. Trihalomethanelevels are high in some parts of Spain. The aim of the presentstudy was to investigate trihalomethane concentrationsin drinking water from distinct water supplies in the provinceof Granada, within the framework of the Childhood and Environment(INMA) study.Methods: Eighty-two tap water samples were collected in twocampaigns during the winter and summer of 2006. An optimizedprocedure based on gas chromatography and massspectrometry was used to determine concentrations of chloroform,bromodichloromethane, dibromochloromethane, andbromoform in the samples.Results: Total trihalomethane concentrations ranged from 0.14to 18.75 g/l in winter samples and from 0.01 to 31.87 g/lin summer samples. The most abundant compound waschloroform. Mean trihalomethane concentrations were 10.13in surface waters and 1.41 g/l in ground waters.Conclusions: The trihalomethane levels found were considerablybelow the maximum permitted level of 100 g/l in the European Union. The values obtained varied widely accordingto the type of water source: the highest concentrations werefound in urban and sub-urban areas, where the water is largelyof surface origin. The presence of trihalomethanes waslower than that reported in other Spanish regions(AU)