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Two North American tall perennials, Sida hermaphrodita L. Rusby and Silphium perfoliatum L. have been recognized in Europe as high-yielding novel bioenergy species. While the latter is recommended for biogas production in Germany, the ligno-cellulosic stems of S. hermaphrodita are widely used as a solid fuel in Poland. Since information on the adaptation of the species to drought and heat and interactions with the CO 2 fertilization effect were lacking, growth chamber experiments were performed with seed-grown and established plants. A full factorial combination of two temperatures, two water levels and two CO 2 levels was applied using the long-term seasonal climate of southwestern Germany as a reference. Non-destructive parameters (length, phenology and senescence) and five harvests served to identify treatment effects on growth and allocation patterns. Shoot material was subjected to chemical and bioenergetic analyses (methane production and energy contents) and NIR-spectroscopy. While seedlings showed stronger growth responses to the treatments than established plants, interspecific differences of the responses were mostly related to allocation patterns and senescence. S. perfoliatum , which has a greater proportion of leaf mass was able to profit from CO 2 fertilization even under dry conditions, while in S. hermaphrodita such effects were absent. Chemical quality (crude protein, ash, fat and fibre) was mainly affected by the reduced water supply and energetic values in S. hermaphrodita and specific methane yields of S. perfoliatum tended to be lower. NIR spectra showed a good representation of percentage leaf mass, which in both species determines the quality of the shoot. [ABSTRACT FROM AUTHOR]

• Cadmium soil pollution and crop accumulation are detectable on national level in China. • Mining activities and sewage irrigation dominate to Cd pollution in China. • Cd pollution in Southwest of China, Middle Yellow River region and North China plain should be taken more seriously. • Cd enrichment models differ with investigated sites and are influenced by pollution sources. Cadmium (Cd) pollution of agricultural soil is of public concern due to its high potential toxicity and mobility. This study aimed to reveal the risk of Cd accumulation in soil and wheat/maize systems, with a specific focus on the source-specific ecological risk, human health risk and Cd enrichment model. For this we investigated more than 6100 paired soil and grain samples with 216 datasets including soil Cd contents, soil pH and grain Cd contents of 85 sites from China. The results showed that mining activities, sewage irrigation, industrial activities and agricultural practices were the critical factors causing Cd accumulation in wheat and maize cultivated sites. Thereinto, mining activities contributed to a higher Cd accumulation risk in the southwest China and Middle Yellow River regions; sewage irrigation influenced the Cd accumulation in the North China Plain. In addition, the investigated sites were classified into different categories by comparing their soil and grain Cd contents with the Chinese soil screening values and food safety values, respectively. Cd enrichment models were developed to predict the Cd levels in wheat and maize grains. The results showed that the models exhibited a good performance for predicting the grain Cd contents among safe and warning sites of wheat (R2 = 0.61 and 0.72, respectively); while the well-fitted model for maize was prone to the overestimated sites (R2 = 0.77). This study will provide national viewpoints for the risk assessments and prediction of Cd accumulation in soil and wheat/maize systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Current atmospheric CO 2 levels are unprecedented for the last 800,000 years and require assessments of their potential effects. Free Air Carbon dioxide Enrichment (FACE) is regarded as the most appropriate exposure system for experimental field investigations. While the early FACE technology involved fans for pre-dilution of CO 2 , now systems both with fans and without fans operating with pure CO 2 are employed. The most often used construction in FACE technology involves peripheral injection from a circular or octagonal plenum with CO 2 release pipes and jet holes surrounding the experimental plot which can create [CO 2 ] gradients across the plot. Here, we present a new FACE design for short vegetation (crops and grassland) that does not involve peripheral injection but distributes CO 2 directly within the plot canopy. The system involves numerous CO 2 release holes in porous tubes that hang down from the upper canopy surface and stretch into the canopy. They can be adjusted in height according to crop growth. Plot size was 2 m × 2 m which allows for a high number of replicates at low CO 2 consumption costs (6.5 tons CO 2 in one season at five replicate plots = 3.5 kg CO 2 per m 2 usable plot area and day during 24hr operation). System performance in terms of CO 2 control was very good both in time and space, with 93% of all instantaneous readings during daylight hours matching ±20% deviation from the set point, and low variation of [CO 2 ] at a given moment within the exposed canopy. Some shading (c. 4% at full canopy development) resulted from the FACE structure at the plots but hardly any other microclimatic artifacts were observed. The FACE system is of modular construction and highly flexible and adaptable to various types of short vegetation. [ABSTRACT FROM AUTHOR]

Leaf nutrient composition and stoichiometry reflect complex interactions of the plant with its environment and are useful traits to explore ecological processes and relationships. In the present study, the foliar elemental compositions of two common Mediterranean woody species, the evergreen broad-leaved Quercus ilex and the coniferous Pinus pinaster growing in an area of Central Italy known for geochemical and geothermal anomalies, were investigated. To assess the site-specific and age-dependent pattern of foliar composition and stoichiometry, macronutrients (C, N, P, K, Mg, S) and trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Sb, V, Zn) were determined in leaves and needles of three different ages (6-, 12- and 24-month-old) collected from metalliferous (geothermal, mining) and rural areas. Leaves of Q. ilex showed comparatively high concentrations of micronutrients (i.e., Cu, Fe and Zn), while needles of P. pinaster accumulated significantly high concentrations of potentially toxic elements (i.e., As, Pb and S). No significant trend was found in elemental concentrations in relation to the age of leaves and needles. Multi-element stoichiometry of P. pinaster was driven by the geochemical heterogeneity of the sites, suggesting plastic adaptation at the sites with the most selective edaphoclimatic conditions (i.e., patches with nutrient poor and metalliferous soils). On the other hand, the content of both nutrients and potentially toxic elements in Q. ilex leaves varied little across the study area, reflecting stoichiometric stability; this is consistent with the ecophysiological features of Q. ilex as a late-successional species with a dominant role in the ecosystems of the Mediterranean area. Our findings demonstrate the value of foliar stoichiometric traits for understanding plant adaptation in a heterogeneous environment and also the consequences of biotic interactions during succession. [Display omitted] • Needles of P. pinaster accumulate potentially toxic elements, such as As, Pb and S. • Nutritional plasticity distinguishes P. pinaster colonizing mining and geothermal sites. • Invariant nutritional status (homeostasis) characterizes the late-successional Q. ilex. • Multi-elemental foliar composition reveals pine-ecosystem interactions. [ABSTRACT FROM AUTHOR]

A field study was carried out in the vicinity of a former battery recycling plant, with heavy metal content (Pb and Zn), the toxicological risk of seed consumption of soybean crops [Glycine Max (L.) Merr.] grown on these soils and their relation with seed quality being evaluated. The concentrations of Pb and Zn in soybeans (roots, stems, pods and seeds) and in top soils were investigated and their potential risk to the health of consumers was estimated. Furthermore, quality-related seed parameters (standard germination test, tetrazolium test, biomass and weight of 1000 seeds) were obtained. The results show that the concentrations of Pb in soybeans at all sites (controls and close to the smelter) were above the maximum permitted levels. Seed quality decreased as the lead concentration increased in seeds from sites near to the former battery recycling plant. Moreover, the greatest accumulation of Zn in seeds was found at sites with high concentrations of Pb in soils. Taking into account these findings, future studies need to be performed in order to evaluate the parameters influencing the mobility and bioavailability of toxic metals in agricultural soils, with the purpose of not only assessing the current state of crops in terms of food security but also evaluating possible soil remediation techniques. [ABSTRACT FROM AUTHOR]