• Energy Research
• 0303 health sciences close
• 6. Clean water close
• 5529875fee5e1f070225a154ae69437b close

The effects of exogenous trehalose (Tre) on salt tolerance of pharmaceutical plant Catharanthus roseus and the physiological mechanisms were both investigated in this study. The results showed that the supplement of Tre in saline condition (250 mM NaCl) largely alleviated the inhibitory effects of salinity on plant growth, namely biomass accumulation and total leaf area per plant. In this saline condition, the decreased level of relative water content (RWC) and photosynthetic rate were also greatly rescued by exogenous Tre. This improved performance of plants under high salinity induced by Tre could be partly ascribed to its ability to decrease accumulation of sodium, and increase potassium in leaves. The exogenous Tre led to high levels of fructose, glucose, sucrose and Tre inside the salt-stressed plants during whole the three-week treatment. The major free amino acids such as proline, arginine, threonine and glutamate were also largely elevated in the first two-week course of treatment with Tre in saline solution. It was proposed here that Tre might act as signal to make the salt-stressed plants actively increase internal compatible solutes, including soluble sugars and free amino acids, to control water loss, leaf gas exchange and ionic flow at the onset of salt stress. The application of Tre in saline condition also promoted the accumulation of alkaloids. The regulatory role of Tre in improving salt tolerance was optimal with an exogenous concentration of 10 mM Tre. Larger concentrations of Tre were supra-optimum and adversely affected plant growth.

AbstractThe increase of extreme drought and precipitation events due to climate change will alter microbial processes. Perturbation experiments demonstrated that microbes are sensitive to environmental alterations. However, only little is known on the legacy effects in microbial systems. Here, we designed a laboratory microcosm experiment using aerobic methane-consuming communities as a model system to test basic principles of microbial resilience and the role of changes in biomass and the presence of non-methanotrophic microbes in this process. We focused on enrichments from soil, sediment, and water reflecting communities with different legacy with respect to exposure to drought. Recovery rates, a recently proposed early warning indicator of a critical transition, were utilized as a measure to detect resilience loss of methane consumption during a series of dry/wet cycle perturbations. We observed a slowed recovery of enrichments originating from water samples, which suggests that the community’s legacy with a perturbation is a contributing factor for the resilience of microbial functioning.

Previous studies of the dynamics of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) have focused on deep stratified lakes. The objective of this study is to present an in-depth investigation of the structure and dynamics of sulfur bacteria (including SRB and SOB) in the water column of shallow freshwater lakes. A cyanobacterial bloom biomass (CBB)-amended mesocosm experiment was conducted in this study, in which water was taken from a shallow eutrophic lake with sulfate levels near 40 mg L-1. Illumina sequencing was used to investigate SRB and SOB species involved in CBB decomposition and the effects of the increases in sulfate input on the water column microbial community structure. The accumulation of dissolved sulfide (∑H2S) produced by SRB during CBB decomposition stimulated the growth of SOB, and ∑H2S was then oxidized back to sulfate by SOB in the water column. Chlorobaculum sequences (the main SOB species in the study) were significantly influenced by increases in sulfate input, with relative abundance increasing approximately four-fold in treatments amended with 40 mg L-1 sulfate (referred to as 40S) when compared to the treatment without additional sulfate addition (referred to as CU). Additionally, an increase in SOB number was observed from day 26-37, concurrent with the decrease in SRB number, indicating the succession of sulfur bacteria. These findings suggest that biological sulfur oxidation and succession of sulfur bacteria occur in the water column during CBB decomposition in shallow freshwater ecosystems, and the increases in sulfate input stimulate microbial sulfur oxidation.

In Asia and Africa the poor tend to live in marginal environments where droughts and floods are frequent. Global warming is expected to increase the frequency of these weather-induced perturbations of crop production. Drought tolerance (DT) has been one of the most difficult traits to improve in genetic crop improvement programs worldwide. Biotechnology provides breeders with a number of new tools that may help to develop more drought tolerant varieties such as marker assisted selection (MAS), molecular breeding (MB), and transgenic plants. This paper assesses some preliminary evidence on the potential impact of biotechnology using data from surveys of the initial DT cultivars developed through one of the main programs in Asia that has been funding DT rice breeding since 1998—The Rockefeller Foundation’s Resilient Crops for Water-Limited Environments program in China, India, and Thailand. Yield increases of DT rice varieties are 5 to 10 percent better than conventional varieties or currently grown commercial varieties than it has been in years. So far we only have experiment station evidence that DT varieties yielded better than conventional or improved varieties during moderate drought years (the one drought year during our study period in South India gave inconclusive results) and in severe drought both the DT and the conventional varieties were either not planted or, if planted, did not yield. We find that the governments could help overcome some of the constraints to the spread of DT cultivars by increasing government funding of DT research programs that take advantage of new biotech techniques and new knowledge from genomics. Secondly, public scientists can make breeding lines with DT traits and molecular markers more easily available to the private seed firms so that they can incorporate DT traits into their commercial hybrids particularly for poor areas. Third, governments can subsidize private sector production of DT seed or provide more government money for state extension services to produce DT varieties.

The arsenic-rich biomass of Pteris vittata is a heavy burden to phytoremediation, but the compositions of extracts recycled from arsenic-rich biomass, such as rutin, may promote broiler growth. As such, this extract can be used to reduce the usage of antibiotics in the broiler industry and the cost of phytoremediation at the same time. Therefore, the critical issues for using extract from arsenic-rich biomass as a growth promoter have been studied, including its effective composition, health and environmental risks, and potential benefits and feasibility. Forty-five compounds were identified in the extract, and they were mainly flavonoids, chlorogenic acids, and proanthocyanidins, which can directly or indirectly influence the growth of broiler. The lifetime carcinogenic risks of broiler edible parts may be maximally increased by 4.75 × 10-9 due to feeding the extract. The arsenic concentration of the farmland fertilized with the excrement from the broiler fed with the extract may increase by 0.00003-0.01857 mg/kg per year. Results revealed a feasible scenario that the sustainability of phytoremediation and broiler industry could be benefited through wastes from each other.

AbstractThe effect of decomposition of Microcystis blooms on the sediment bacterial communities was investigated in a 14‐day mesocosm experiments under dark and anoxic condition with three differing levels of Microcystis spp. biomass (from 20 to 2000 µg L−1) as measured by chlorophyll‐a (Chl‐a) concentration in the water column. Sediment samples were collected on days 0 and 14 for bacterial community composition (BCC) analysis, based on rapid decreases in the Chl‐a concentration of water column. The BCC was determined by denaturing gradient gel electrophoresis and sequencing of predominant bands. The results showed that after Microcystis decomposition (day 14), the bacterial phylotype diversity in the sediment increased in enclosures with added Microcystis, and the relative abundance of bacteria affiliated with Bacteroidetes and Verrucomicrobia strongly increased. Canonical correspondence analysis showed that organic matter and Chl‐a contributed significantly to the changes in sediment bacterial communities during Microcystis decomposition. The present results demonstrate Microcystis decomposition may directly and indirectly influence the BCC of the sediment.

SummaryAnaerobic ammonium oxidation with an anode as the electron acceptor was realized in a dual‐chamber microbial electrolysis cell (MEC). Nitrate was the main product that accounted for approximately 95% of ammonium consumed, but nitrite was also detectable. Using 16S ribosomal RNA analysis, we found that the microbial community attached to the electrode was dominated by Nitrosomonas europaea (40.3%) and the genus Empedobacter (34.7%), but no anammox bacteria were detected. Nitrosomonas europaea was shown to be necessary with an inhibition assay using allylthiourea. Certain soluble metabolites were found to have an important effect on the current production. These results show that there are many ways to oxidize ammonium biologically.

Pit mud is a typical artificial ecosystem for Chinese liquor production. Clostridium inhabiting pit mud plays essential roles in the flavor formation of strong-flavor baijiu. The relative abundance of Clostridium increased with pit mud quality, further influencing the quality of baijiu.