Bottom Velocity Observations Directly under the Gulf Stream

Speeds as high as 44 centimeters per second were observed 200 meters above the ocean bottom under the Gulf Stream at 70 degrees W longitude and were associated with time-dependent motion that had a speed range of 40 centimeters per second and a time scale of about 30 days. These deep current fluctuations appear to be coupled with fluctuations in the surface position of the Stream and with surface and bottom current fluctuations 200 kilometers to the north.     

Root architectural traits and yield: exploring the relationship in barley breeding trials

Root system architecture is fundamental to resource capture and productivity of cereal crops. Understanding the genetics modulating root development will empower plant breeders to design cultivars with optimal root systems for the target environment. Here, we investigate the genetic association between seminal root traits and yield in elite barley (Hordeum vulgare L.) germplasm. A panel of 216 breeding lines from the Northern Region Barley Breeding program in Australia, genotyped with Diversity Arrays Technology markers, were characterised for seminal root angle and number. A high degree of phenotypic variation was evident in the population, ranging from 12.0° to 89.4° and 4.8 to 6.1 for root angle and number, respectively. A quantitative trait locus for root angle (qRA-5) was detected on chromosome 5H and co-located with the previously described RAQ2. The genetic relationship between seminal root traits and yield for the panel was investigated using root phenotypes and yield data from 20 field trials. Genetic correlations with yield ranged from ??0.21 to 0.36 for root angle and from ??0.20 to 0.25 for root number. The direction and magnitude of the correlations for both root traits varied across the environments, but overall root angle was deemed more strongly associated with yield. Here we provide insight into the root phenotypes of breeding lines and deliver a first look at the genetic relationship between root architectural traits and yield in barley breeding trials.     

Nutritional Status of Mediterranean Trees Growing in a Contaminated and Remediated Area

Soil contamination may contribute to forest decline, by altering nutrient cycling and acquisition by plants. This may hamper the establishment of a woody plant cover in contaminated areas, thus limiting the success of a restoration program. We studied the nutritional status of planted saplings of Holm oak (Quercus ilex subsp. ballota (Desf.) Samp.), white poplar (Populus alba L.), and wild olive tree (Olea europaea var. sylvestris Brot.) in the Guadiamar Green Corridor (SW Spain) and compared it with established adult trees. Soils in this area were affected by a mine-spill in 1998 and a subsequent restoration program. The spill resulted in soil acidification, due to pyrite oxidation, and deposited high concentrations of some trace elements. In some sites, we detected a phosphorus deficiency in the leaves of Q. ilex and O. europaea saplings, as indicated by a high N:P ratio (>16). For O. europaea, soil contamination explained 40% of the variability in leaf P and was negatively related to chlorophyll content. Soil pH was a significant factor predicting the variability of several nutrients, including Mg, P, and S. The uptake of Mg and S by P. alba was greater in acidic soils. The monitoring of soil pH is recommended since long-term effects of soil acidification may negatively affect the nutritional status of the trees.     

What do babies eat? Evaluation of a food frequency questionnaire to assess the diets of infants aged 6 months

OBJECTIVE: To evaluate the relative validity of a food frequency questionnaire (FFQ) for assessing nutrient intakes in 6-month-old infants. DESIGN AND SETTING: The FFQ was developed to assess the diets of infants born to women in the Southampton Women's Survey (SWS), a population-based survey of young women and their offspring. The energy and nutrient intakes obtained from an interviewer-administered FFQ were compared with those obtained from a 4-day weighed diary. SUBJECTS AND METHODS: A sub-sample of 50 infants aged 6 months from the SWS had their diets assessed by both methods. The FFQ recorded the frequencies and amounts of milks, baby foods, regular foods and drinks consumed by the infants over the previous seven days. The diaries recorded the weights of all foods and drinks consumed by the infants on four separate days within 15 days following FFQ completion. RESULTS: Spearman rank correlation coefficients for intakes of energy, macronutrients and 18 micronutrients, determined by the two methods, ranged from r = 0.39 to 0.86; adjustment for energy intake tended to increase the correlation coefficients, range r(a) = 0.55 to 0.89. Bland-Altman statistics showed that mean differences between methods were in the range of -12.5% to +12.5% except for vitamin B12 (-18.9%). CONCLUSION: Although there were differences in absolute energy and nutrient intakes between methods, Spearman rank correlation coefficients indicated reasonable agreement in the ranking of intakes. The interviewer-administered FFQ is a useful tool for assessing energy and nutrient intakes of healthy infants aged about 6 months.     

Analysing the preferential transport of lead in a vegetated roadside soil using lysimeter experiments and a dual-porosity model

Lead (Pb) from the traffic accumulates in roadside soils, which are usually vegetated to control erosion. Plants release soluble organic substances that bind Pb. Root macropores also create preferential pathways through which water can flow. Both these processes may enhance Pb mobility. We used large lysimeters to investigate the transport of Pb in a contaminated (445 mg Pb kg^?1) soil under vegetation (Phacelia tanacetifolia). Despite the high soil pH (7.2), Pb leached into the drainage water during the 5‐month experiment. The fast response of the system to intense rainfall events indicated the presence of preferential flow. By comparing Pb concentrations in filtered and unfiltered leachates, we found that Pb was leaching primarily on suspended material. An increase in Pb concentration in the leachate at the end of the experiment indicated the remobilization of Pb, possibly by decaying vegetation. We parameterized the dual‐porosity MACRO model using the experimental results. The simple parameterization of MACRO used to simulate the Pb concentrations in the drainage water produced an overall model efficiency of 0.81: MACRO simulated the Pb concentrations well, but it failed to predict the observed increase of Pb in the leachate at the end of the experiment. The model gave the best prediction of Pb concentrations with a small partition coefficient (k_d= 150 cm³ g^?1). Long‐term simulations of Pb mobility showed that for our specific conditions preferential flow was the main process determining the fate of Pb.     

A regional soil survey approach for upgrading from flood to sprinkler irrigation in a semi-arid environment

Increasing pressure on water resources in Spain is forcing farmers to move from flood to pressurized water application. Initial recommendations for this upgrading require soil survey information, especially in areas prone to soil salinity. In this article a 3158 ha soil survey at a scale of 1:25,000 is presented. Soil series are split in phases based on the texture of the surface layer, slope, and salinity. Available water holding capacity (AWHC), to a depth of 1.5 m or to a lithic or paralithic contact, texture and coarse components in the surface horizons, and salinity mapped as discrete soil units are combined to develop a regional soil suitability map for irrigation upgrade. To minimize soil erosion and salt mobilization in the soils, our recommendations are: (i) maintain and improve flood irrigation on 296 ha, (ii) develop standard sprinkler irrigation on 2261 ha, and (iii) move to high frequency sprinkler irrigation on 601 ha. This research demonstrates the importance of soil survey as part of the decision making process for upgrading the regional irrigation systems.     

Co-oxidation of beta-carotene catalyzed by soybean and recombinant pea lipoxygenases

A number of products including apocarotenal, epoxycarotenal, apocarotenone, and epoxycarotenone generated by lipoxygenase (LOX) catalyzed co-oxidation of beta-carotene have been tentatively identified through the use of GC/MS and HPLC combined with photodiode array detection. Because of the large number of high molecular weight products detected and their probable chemical structures, a co-oxidation mechanism is proposed that involves random attack along the alkene chain of the carotenoid by a LOX-generated linoleoylperoxyl radical. It is suggested that a direct release from the enzyme of the radical, which initiates the co-oxidation of beta-carotene, is greater for pea LOX-3 than for pea LOX-2 or soybean LOX-1. It is proposed that further products may be formed by free radical propagated reactions and that the formation of 1,10- and 1,14-dicarbonyl compounds may arise by secondary oxidation of the primary products.