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Photosynthetic pigment composition has been a major study target in plant ecophysiology during the last three decades. Although more than 2000 papers have been published, a comprehensive evaluation of the responses of photosynthetic pigment composition to environmental conditions is not yet available. After an extensive survey, we compiled data from 525 papers including 809 species (subkingdom Viridiplantae) in which pigment composition was described. A meta-analysis was then conducted to assess the ranges of photosynthetic pigment content. Calculated frequency distributions of pigments were compared with those expected from the theoretical pigment composition. Responses to environmental factors were also analysed. The results revealed that lutein and xanthophyll cycle pigments (VAZ) were highly responsive to the environment, emphasizing the high phenotypic plasticity of VAZ, whereas neoxanthin was very stable. The present meta-analysis supports the existence of relatively narrow limits for pigment ratios and also supports the presence of a pool of free 'unbound' VAZ. Results from this study provide highly reliable ranges of photosynthetic pigment contents as a framework for future research on plant pigments., (© 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.)

Current methods for the study of pigments involve freezing in liquid nitrogen and storage at -80 degrees C or lyophilization until HPLC analysis. These requirements greatly restrict ecophysiological research in remote areas where such resources are hardly available. We aimed to overcome such limitations by developing several techniques not requiring freezing or lyophilization. Two species with contrasting foliar characteristics (Olea europaea and Taraxacum officinale) were chosen. Seven preservation methods were designed, optimized and tested in a field trial. These protocols were compared with a control immediately frozen after collection. Pigments and tocopherols were analysed by HPLC. Main artefacts were chlorophyll epimerization or phaeophytinization, carotenoid isomerization, altered de-epoxidation index and tocopherol degradation. Among all methods, sample desiccation in silica gel provides robust samples (pigment composition was unaffected by storage time or temperature) and almost unaltered pigment profiles, except for a shift in epoxidation state. Although liquid nitrogen freezing and subsequent lyophilization or freezer storage were preferred, when these facilities are either not available or not suitable for long-distance transport, desiccation with silica gel, passive extraction in acetone and/or storage of fresh samples in water vapour saturated atmospheres enable a complete pigment characterization. Silica gel is advisable for long-term sample conservation.

The authors address the causes and impact of errors in publising plant science studies. Topics discussed include the results of an analysis of survey data from 525 papers from 1991-2011, the definitions of the each type of errors in publishing, and several potential sources of errors that may occur at any stage of the research process.

Duckweed (Lemna minor L.) plants acclimated to three light regimes: 50 low light (LL), 300 medium light (ML) and 500 high light (HL) μmol m–2 s–1 photosynthetic photon flux density (PPFD) increased photoprotective potential according to irradiance status as shown by the two- to fourfold higher contents of xanthophyll cycle pigments (VAZ), total glutathione (GLU) and α-tocopherol. LL, ML and HL plants were then exposed to Cd or Zn for 9 d and illuminated at 300 μmol m–2 s–1. Both metals inhibited plant growth and caused the accumulation of phytochelatins, but phytochelatin synthesis did not result in glutathione depletion in the Zn treatments. An antioxidative response was observed with a large increase in total ascorbate (ASC), tocopherol and VAZ pigments. These mechanisms seemed to be able to partly alleviate the adverse effects of Zn but not of Cd. The damage caused by Cd led to the complete bleaching of chlorophylls (Chl) at the end of the experiment in HL and ML plants. The pattern of antioxidative response was different when comparing Cd and Zn treatments, with a much larger accumulation of ASC in Cd-treated plants, and GLU on Zn-treated plants. Paradoxically, LL plants that initially had a lower level of photoprotection, were much less affected by Cd or Zn. Thus, these plants showed very small or no reductions in photochemical efficiency, chlorophyll content and a lower ASC accumulation. Although we could not explain this paradoxical effect, we can conclude that other reasons related to the previously light grown conditions could be more determinant to explain heavy metal induced damage than the basal level of antioxidant content in Lemna plants. [Copyright &y& Elsevier]

Increasing soil loss and the scarcity of useful land requires new reusing strategies. Thus, recovery of polluted soils recovery offers a chance for economic and social regeneration. With this objective, different soil cleaning technologies have been developed during the last few decades. On one hand, classical physical and/or chemical technologies can be found which are efficient, but have high costs and impacts upon ecosystems. On the other hand, biological methods (such as phytoremediation, bioremediation and vermiremediation) are relatively cost effective and eco-friendly, but also more time-consuming. These biological methods and their yields have been widely studied but little is known about the interaction between different soil cleaning methods. The combination of different biological strategies could lead to an improvement in remediation performance. Hence, in the present work, different micro-, vermi- and phyto-remediation combinations are applied in a sewage sludge polluted landfill in Gernika-Lumo (Basque Country) which was used as a disposal point for decades, in search of the treatment (single) or combination (dual or triple) of treatments with best remediation yields. Eight experimental groups were applied (n=3) placing earthworms (E), bacteria (B), plants (P), bacteria+earthworms (B+E), bacteria+plants (B+P), plants+earthworms (P+E) plants+bacteria+earthworms (P+B+E) and a non-treated (N.T.) group in the experimental plot (Landfill 17), for 12 months. In order to assess the efficiency of each treatment, a complete characterization (chemical and ecotoxicological) was carried out before and after remediation. Results showed high removal rates for dieldrin (between 50% and 78%) in all the experimental groups. In contrast, removal rates around 20–25% were achieved for heavy metals (Cd 15%–35%; Ni 24%–37%; Pb 15%–33%; Cr 7%–39%) and benzo(a)pyrene (19.5%–28%). The highest reductions were observed in dual (P+E, B+E) and triple (P+B+E) treatments. The best elimination yields were obtained after P+B+E treatment, as highlighted by the battery of ecotoxicological tests and bioassays performed with earthworms, plants and bacteria. Unlabelled Image • Combining bioremediation strategies offers better returns than individual techniques alone. • A dual: chemical and ecotoxicological approach is needed to understand and evaluate remediation processes. • Triple treatment combining plants, bacteria and earthworms showed best chemical yields and soil health improvements. [ABSTRACT FROM AUTHOR]