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We investigated the ability of the aquatic fern Azolla to take up ciprofloxacin (Cipro), as well as the effects of that antibiotic on the N-fixing process in plants grown in medium deprived (-N) or provided (+N) with nitrogen (N). Azolla was seen to accumulate Cipro at concentrations greater than 160 μg g −1 dry weight when cultivated in 3.05 mg Cipro l −1 , indicating it as a candidate for Cipro recovery from water. Although Cipro was not seen to interfere with the heterocyst/vegetative cell ratios, the antibiotic promoted changes with carbon and nitrogen metabolism in plants. Decreased photosynthesis and nitrogenase activity, and altered plant's amino acid profile, with decreases in cell N concentrations, were observed. The removal of N from the growth medium accentuated the deleterious effects of Cipro, resulting in lower photosynthesis, N-fixation, and assimilation rates, and increased hydrogen peroxide accumulation. Our results shown that Cipro may constrain the use of Azolla as a biofertilizer species due to its interference with nitrogen fixation processes. [ABSTRACT FROM AUTHOR]

Non-structural carbohydrates ( NSC) play a crucial role in tree resistance and resilience to drought. Stem sapwood parenchyma is among the largest storage tissue for NSC in mature trees. However, there is a limited mechanistic understanding of how NSC reserves, stem parenchyma abundance and growth rates are interrelated, and how they respond to changing water availability., We quantified NSC, ray parenchyma abundance and ring width along four successive 5-year radial sapwood segments of the stem of 40 mature Pinus sylvestris trees from a 10-year irrigation experiment conducted at a xeric site in Switzerland., Percentage of ray volume ( PERPAR) varied from 3·75 to 8·94% among trees, but showed low intra-individual variability. PERPAR responded positively to irrigation with a lag of several years, but was unrelated to % NSC. % NSC was lower in wider rings. However, wider rings still contained a larger NSC pool that was positively related to next year's ring growth., Our results suggest that stem ray parenchyma does not limit NSC storage capacity, but responds to long-term environmental drivers with years of delay. The observed carbon allocation patterns indicate a prioritization of storage over growth independent of growth conditions, likely as a mechanism to ensure long-term survival. Furthermore, NSC pool size proved to be a determinant for the inter-annual autocorrelation in tree-ring growth. Our study highlights the importance of long-term multi-parameter studies to better understand tree responses to environmental variability at different time-scales., A is available for this article. [ABSTRACT FROM AUTHOR]

Globally, it is estimated that 20 million hectares of arable land are irrigated with water that contains residual contributions from domestic liquids. This potentially poses risks to public health and ecosystems, especially due to heavy metals, which are considered dangerous because of their potential toxicity and persistence in the environment. The Villavicencio region (Colombia) is an equatorial area where rainfall (near 3000 mm/year) and temperature (average 25.6 ◦C) are high. Soil processes in tropical conditions are fast and react quickly to changing conditions. Soil properties from agricultural fields irrigated with river water polluted by a variety of sources were analysed and compared to non-irrigated control soils. In this study, no physico-chemical alterations were found that gave evidence of a change due to the constant use of river water that contained wastes. This fact may be associated with the climatic factors (temperature and precipitation), which contribute to fast degradation of organic matter and nutrient and contaminants (such as heavy metals) leaching, or to dilution of wastes by the river. [ABSTRACT FROM AUTHOR]

In a climate change scenario, successful modeling of the relationships between plant-soil-meteorology is crucial for a sustainable agricultural production, especially for perennial crops. Grapevines (Vitis vinifera L. cv Chardonnay) located in eight experimental plots (Burgundy, France) along a hillslope were monitored weekly for 3 years for leaf water potentials, both at predawn (ψpd) and at midday (ψstem). The water stress experienced by grapevine was modeled as a function of meteorological data (minimum and maximum temperature, rainfall) and soil characteristics (soil texture, gravel content, slope) by a gradient boosting machine. Model performance was assessed by comparison with carbon isotope discrimination (δ13C) of grape sugars at harvest and by the use of a test-set. The developed models reached outstanding prediction performance (RMSE < 0.08 MPa for ψstem and < 0.06 MPa for ψpd), comparable to measurement accuracy. Model predictions at a daily time step improved correlation with d13C data, respect to the observed trend at a weekly time scale. The role of each predictor in these models was described in order to understand how temperature, rainfall, soil texture, gravel content and slope affect the grapevine water status in the studied context. This work proposes a straight-forward strategy to simulate plant water stress in field condition, at a local scale; to investigate ecological relationships in the vineyard and adapt cultural practices to future conditions. [ABSTRACT FROM AUTHOR]

* Premise of the study: Temperature and water potential for germination based on the thermal and hydrotime models have been successfully applied in predicting germination requirements of physiologically dormant seeds as well as nondormant seeds. However, comparative studies of the germination requirements of physically dormant seeds from different ecosystems have not been done. * Methods: Germination of scarified seeds of four legume species collected from the Qing-Tibetan Plateau and of four collected in the Alax Desert in China was compared over a range of temperatures and water potentials based on thermal time and hydrotime models. * Key results: Seeds of species from the Qing-Tibetan Plateau had a lower base temperature (Tb) and optimal temperature (To) for germination than those from the Alax Desert. Seeds of the four species from the Qing-Tibetan Plateau germinated to high percentages at 5°C, whereas none of the four desert species did so. Seeds of species from the Alax Desert germinated to a high percentage at 35°C or 40°C, while no seeds of species from the Qing-Tibetan Plateau germinated at 35°C or 40°C. The base median water potential [Ψb(50)] differed among species but not between the two habitats. * Conclusions: The thermal time and hydrotime models accurately predicted the germination time course of scarified seeds of most of the eight species in response to temperature and water potential; thus, they can be useful tools in comparative studies on germination of seeds with physical dormancy. Habitat temperatures but not rainfall is closely related to germination requirements of these species. [ABSTRACT FROM AUTHOR]

Chlorophyll a fluorescence is established as a rapid, non-intrusive technique to monitor photosynthetic performance of plants and algae, as well as to analyze their protective responses. Apart from its utility in determining the physiological status of photosynthesizers in the natural environment, chlorophyll a fluorescence-based methods are applied in ecophysiological and toxicological studies to examine the effect of environmental changes and pollutants on plants and algae (microalgae and seaweeds). Pollutants or environmental changes cause alteration of the photosynthetic capacity which could be evaluated by fluorescence kinetics. Hence, evaluating key fluorescence parameters and assessing photosynthetic performances would provide an insight regarding the probable causes of changes in photosynthetic performances. This technique quintessentially provides non-invasive determination of changes in the photosynthetic apparatus prior to the appearance of visible damage. It is reliable, economically feasible, time-saving, highly sensitive, versatile, accurate, non-invasive and portable; thereby comprising an excellent alternative for detecting pollution. The present review demonstrates the applicability of chlorophyll a fluorescence in determining photochemical responses of algae exposed to environmental toxicants (such as toxic metals and herbicides). [Copyright &y& Elsevier]

The aim of the study was to use bioassays to evaluate the toxicity of pore water, sediments and sediments elutriates. Furthermore, a possible relationship between observed toxicity and results of chemical analysis was examined. Sediment (0–10cm) samples were collected from 21 locations in Zeslawice reservoir, Southern Poland using an Ekman sampler. Toxicity assessment of the sediment and pore water samples was performed using direct-contact tests Phytotoxkit/Phytotestkit and Microtox®. Inhibition of seed germination in the test plants was from −25 to 38 percent for sediment and from 0 to 50 percent for pore water, whereas inhibition of root growth was within a range from −42 to 37 percent for sediment and from −49 to 37 percent for pore water. Depending on the sediments, Vibrio fischeri luminescence inhibition was from −18 to 40 percent for sediments elutriates and from −12 to 28 percent for pore water. The toxicity tests showed a positive correlation between metals and the root growth inhibition in Lepidium sativum and Sinapis alba as well as the luminescence inhibition in V. fischeri. No significant correlations were found between the inhibition of luminescence and the phytotoxicity assays, so these analyses do not show a similar sensitivity to toxicants in the sediments. While estimating the sensitivity of the performed biotests, the highest number of toxic responses was recorded in the Microtox® test towards V. fischeri. Among the plant species, Sorghum saccharatum appears to be the most sensitive plant species. Most of the examined sediment samples (67 percent) were classified as class II (low-toxic samples, low acute hazard) and 33 percent of the examined samples were class I (no essential toxic effect, non-toxic sample, no acute hazard) in terms of toxicity. Most of the pore water samples (71 percent) were also classified as class II. [Copyright &y& Elsevier]

Dechloranes (Decs), including Dechlorane Plus (DP) and Dechlorane (Dec) 602, 603, 604, are used as flame retardants. Fifty four samples were collected in a river in northeastern China and analyzed for Decs by gas chromatography/mass spectrometry. The average concentrations of total DP (syn- and anti-) in water, sediment, air, reed (Phragmites australis), and fish (E. elongatus) were 0.30±0.24 (mean±SD) ngL−1, 1.3±0.69ngg−1 dry weight (dw), 0.25±0.18ngm−3, 0.63±0.18ngg−1 wet weight (ww), and 29±20ngg−1 lipid weight (lw), respectively. While Dec 602 and Dec 603 were detected in most of sediment and fish samples, no Dec 604 was found in any of the investigated environmental matrices. The mean ratio of syn-DP to total DP (f syn ) in water, sediment, reed, and fish were 0.28, 0.25, 0.27 and 0.47, suggesting depletion in abiota and enrichment in biota for syn-DP. It was found that biota-sediment accumulation factor (BSAF) was 4.7 for Dec 602, 0.88 for syn-DP, and 0.33 for anti-DP. [Copyright &y& Elsevier]

The objectives of this experimental study were to examine the interaction between metal contaminated aquatic environments and element uptake by Echinodorus amazinocus and Cryptocoryne undulata. Changes in element concentrations were investigated in three phases in aquatic environments: water, pore water and sediment. Additionally, the amounts of partial elements, relative uptakes, translocation factor and bio-concentration factor were evaluated for each plant. Growth analyses of both plants, as well as physical parameters of the water quality obtained from the reactors, were statistically evaluated by a two-sample t-test. Following the analyses, it was observed that the amount of all of the elements in each of the phases was different for each intermittent sample. Studies with C. undulata and E. amazinocus demonstrated that the concentration of all of the elements in the plants was changing relatively. It was also found that existing environmental conditions did not affect plant life negatively. [Copyright &y& Elsevier]

The objective of this research was to identify genotypes tolerant to stress caused by NaCl and the mixture of NaCl, CaCl2 and MgCl2 in irrigation water in the early stages of development. The levels of electrical conductivity of saturation extract were 0, 0.25, 5.0 and 7.5dS m-1. The tolerance of cowpea was evaluated by the relative reduction in shoot dry matter of each genotype. The genotype CE-182 had more tolerant levels of 2.5, 5.0 and 7.5dS m-1 in saline water with NaCl. In the solution mixture of salts, the genotypes and CE-9 and CE-551 were the most tolerant. According to the results obtained by clustering using the UPGMA method it can verified that the most promising combinations for crosses which obtained superior progenies in the development of cultivars tolerant to salinity were found between genotypes CE-182 and CE-250 and between CE-551 and CE-9. [ABSTRACT FROM AUTHOR]

Abstract: Egeria densa has ability to grow in heavy metal contaminated and polluted bodies of water. Shoots exposed to Cd at concentrations up to 300μM for 7 days showed a pronounced decrease in chlorophyll a and in total protein concentration. Thiol-containing compounds and low-molecular-weight polypeptides were detected in Cd-treated plant extracts by gel filtration chromatography. Two Cd-binding fractions, a thiol-enriched fraction and a non-thiol fraction with a lower molecular weight were identified in extracts by gel filtration. The main fraction of thiol-containing polypeptide, purified by gel filtration and anion-exchange chromatography had a molecular weight of ∼10kDa. This peptide was characterized by a broad absorption band specific to mercaptide bonds and Cd-sensitive fluorescence emission of aromatic amino acid residues. Our results indicate that cadmium exposure of plants resulted in both a formation of thiol-enriched cadmium complexing peptides and a synthesis of low-molecular-weight metal chelators. The putative role of these compounds in Cd detoxification is discussed. [Copyright &y& Elsevier]

The effect of light and water on aromatic rice remain largely unclear. A pot experiment was conducted to investigate the influences of light-water treatments (CK: natural light and well-watered conditions, WS: natural light and water-stressed conditions, LL: low light and well-watered conditions, LL-WS: low light and water-stressed treatment) on yield and 2-acetyl-1-pyrroline (2AP) formation in aromatic rice. Compared with CK, the light-water treatments decreased grain yield (10.32–39.19%) due to reductions in the filled grain percentage and total dry weight, in the regulation of biomass distribution, and in the attributes of gas exchange and antioxidant response parameters. The 2AP content in grains increased in the LL treatment (5.08–16.32%) but decreased in the WS treatment compared with that in CK. The changes in 2AP were associated with changes in 2AP formation-related traits and element content. Low light and water stress led to yield declines in aromatic rice, but low light alleviated the decrease in 2AP content caused by water stress. [ABSTRACT FROM AUTHOR]

Aquatic plants are vital to the life of many species that live in lakes, rivers, ponds, and streams. According to recent studies, aquatic plants such as duckweed take in many pollutants in these water sources faster than bacteria can degrade them. To determine the effect of water pollution on aquatic plants, the growth of aquatic plants in different types of water was studied. Nine groups of duckweed from Maumee Bay State Park were collected and grown in three different types of water at room temperature: Maumee River water, tap water, and chlorinated water (containing eight times the chlorine of tap water). Diameter, area, water, and air temperature were recorded on three different days. Total growth was determined by measuring the diameter of the group then calculating the area. The duckweed did not grow in chlorinated water, but grew equally well in tap water and in Maumee River water. In conclusion, this experiment was designed to discover if aquatic plants can be an indicator for water pollution. The investigation did not show a definite answer to this question. If this experiment was to be revisited, a change in the hypothesis would take place because aquatic plants can adapt to water with varying qualities. The experiment may reveal different and more definite results if it was re-done. The duration of the experiment should be extended for further research. Some pollutants could possibly extend the life of aquatic plants because they have the ability to take in water pollutants faster than bacteria can degrade them. [ABSTRACT FROM AUTHOR]