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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]

Studies of soil Cd and Zn are often performed on sites that are contaminated or have deficient Zn conditions. Soil characteristics and crop management could impact the soil mobility and uptake of Cd and Zn, even when considering unpolluted Cd soils and adequate soil Zn levels. The concentrations of these two metals were assessed in soil and silage maize under five P fertilization treatments at two growth stages under low Cd and sufficient Zn conditions. Pearson correlation coefficients and stepwise linear regressions were calculated to investigate the soil characteristics influencing the bioavailable metal fraction in soil and the metal concentration in silage maize. P treatments did not impact Cd accumulation in maize; however, the Zn uptake was affected by P placement at the leaf development stage. From early development to maturity, the Cd level in maize decreased to 10% of the initial uptake, while the Zn level decreased to 50% of the initial uptake. This reduction in both metals may be attributed to a dilution effect derived from high biomass production. Silage maize could alleviate the initial Cd uptake while diminishing the depressant effect of P fertilizer on Zn concentration. Further research is required to understand the effect of P fertilizer on Cd uptake and its relation to Zn under field conditions at early and mature stages. [ABSTRACT FROM AUTHOR]

The analysis of physiological parameters is important to understand the link between plant phenotypes and their genetic bases, and therefore is needed as an important element in the analysis of model and crop plants. The activities of enzymes involved in primary carbohydrate metabolism have been shown to be strongly associated with growth performance, crop yield, and quality, as well as stress responses. A simple, fast, and cost-effective method to determine activities for 13 key enzymes involved in carbohydrate metabolism has been established, mainly based on coupled spectrophotometric kinetic assays. The comparison of extraction buffers and requirement for dialysis of crude protein extracts resulted in a universal protein extraction protocol, suitable for the preparation of protein extracts from different organs of various species. Individual published kinetic activity assays were optimized and adapted for a semi-high-throughput 96-well assay format. These assays proved to be robust and are thus suitable for physiological phenotyping, enabling the characterization and diagnosis of the physiological state. The potential of the determination of distinct enzyme activity signatures as part of a physiological fingerprint was shown for various organs and tissues from three monocot and five dicot model and crop species, including two case studies with external stimuli. Differential and specific enzyme activity signatures are apparent during inflorescence development and upon in vitro cold treatment of young inflorescences in the monocot ryegrass, related to conditions for doubled haploid formation. Likewise, treatment of dicot spring oilseed rape with elevated CO2 concentration resulted in distinct patterns of enzyme activity responses in leaves. [ABSTRACT FROM AUTHOR]

In general, yield and fruit quality strongly rely on efficient nutrient remobilization during plant development and senescence. Transcriptome changes associated with senescence in spring oilseed rape grown under optimal nitrogen supply or mild nitrogen deficiency revealed differences in senescence and nutrient mobilization in old lower canopy leaves and younger higher canopy leaves. Having a closer look at this transcriptome analyses, we identified the major classes of seed storage proteins (SSP) to be expressed in vegetative tissue, namely leaf and stem tissue. Expression of SSPs was not only dependent on the nitrogen supply but transcripts appeared to correlate with intracellular H2O2 contents, which functions as well-known signaling molecule in developmental senescence. The abundance of SSPs in leaf material transiently progressed from the oldest leaves to the youngest. Moreover, stems also exhibited short-term production of SSPs, which hints at an interim storage function. In order to decipher whether hydrogen peroxide also functions as a signaling molecule in nitrogen deficiency-induced senescence, we analyzed hydrogen peroxide contents after complete nitrogen depletion in oilseed rape and Arabidopsis plants. In both cases, hydrogen peroxide contents were lower in nitrogen deficient plants, indicating that at least parts of the developmental senescence program appear to be suppressed under nitrogen deficiency. [ABSTRACT FROM AUTHOR]