The Physiological Response of Salix matsudana for Water Pollution by 2,4-Dinitrophenol.

In this study, the effects of different concentrations of 2,4-dinitrophenol (2,4-DNP) stress on physiological parameters, as well as the uptake and removal of 2,4-DNP in Salix matsudana, were investigated using hydroponic simulation experiments to explore the potential of the use of Salix matsudana in the phytoremediation of wastewater polluted by 2,4-DNP. The results showed that PN (net photosynthetic rate), Tr (transpiration rate), Gs (stomatal conductance), Ls (stomatal limitation value), Fv/Fm (maximal quantum yield of PSII photochemistry), and qp (photochemical quenching coefficient) of Salix matsudana seedlings showed an overall decreasing trend, while Ci (intercellular CO2 concentration) showed an increasing trend with the increase in 2,4-DNP concentration. The net photosynthetic rate and intercellular carbon dioxide concentration showed an opposite trend in the leaves with the increase in 2,4-DNP stress concentration, and the inhibition of net photosynthesis by 2,4-DNP on Salix matsudana seedlings was mainly based on non-stomatal factors. In the 15 d incubation experiment, the values of SOD (superoxide dismutase), POD (peroxidase), and CAT (catalase) indexes were higher at low concentrations of 2,4-DNP stress, and all three enzymes reached their maximum values at 10 mg L-1 of 2,4-DNP and then decreased. Salix matsudana seedlings could tolerate 2,4-DNP stress well, which did not exceed 20 mg L-1. The toxicity of 2,4-DNP solution was significantly reduced after purification by Salix matsudana seedlings. The removal rate of 2,4-DNP was higher than 80% in each treatment group by Salix matsudana purified after 15 days. When the concentration of 2,4-DNP reached 20 mg L-1, the contents of MDA (malonicdialdehyde) were 55.62 mmol g-1, and the values of REC (relative conductivity) and LD (leaf damage) were 63.51% and 59.93%, respectively. The structure and function of the cell membrane in leaves were seriously damaged. With the increase in 2,4-DNP concentration, the removal of 2,4-DNP by Salix matsudana seedlings showed a decreasing trend. When the 2,4-DNP concentration was 5 mg L-1, the highest removal rate of 2,4-DNP by Salix matsudana seedlings was 95.98%, while when the 2,4-DNP concentration was 20 mg L-1, the highest removal rate was 86.76%. It is noted that the suitable, recommended concentration for the phytoremediation of 2,4-DNP contamination by Salix matsudana seedlings is between 8.81 and 13.78 mg L-1.

Enhanced phytoremediation of 2,4-DNP-contaminated wastewater by Salix matsudana Koidz with MeJA pretreatment and associated mechanism.

2,4-Dinitrophenol (2,4-DNP) is recognized as an emerging contaminant due to its high toxicity and poor biodegradability, posing a threat to animals, plants, and human health. The efficient removal of 2,4-DNP remains a challenging issue in phytoremediation research, particularly because of its toxic effects on plants. To address this, a hydroponic simulation experiment was conducted to investigate the impact of adding exogenous methyl jasmonate (MeJA) on the tolerance and purification capabilities of Salix matsudana Koidz (S. matsudana) seedlings exposed to 2,4-DNP. The results indicated that the addition of exogenous MeJA mitigated the damage caused by 2,4-DNP to S. matsudana seedlings by enhancing the activity of antioxidant enzymes, reducing excess reactive oxygen species (ROS), lowering membrane lipid peroxidation, and minimizing membrane damage. Notably, the most effective alleviation was observed with the addition of 50 mg·L-1 MeJA. Furthermore, exogenous MeJA helped maintain the biomass indices of S. matsudana seedlings under 2,4-DNP stress and increased the removal efficiency of 2,4-DNP by these seedlings. Specifically, the addition of 50 mg·L-1 MeJA resulted in a removal percentage of 79.57%, which was 11.88% higher than that achieved with 2,4-DNP treatment. In conclusion, exogenous MeJA can improve the plant resistance and enhance 2,4-DNP phytoremediation.

Using Sweet Sorghum Varieties for the Phytoremediation of Petroleum-Contaminated Salinized Soil: A Preliminary Study Based on Pot Experiments.

Using energy plants to repair salinized soils polluted by petroleum is an efficient way to solve the problem of farmland reduction and prevent pollutants from entering the food chain simultaneously. In this study, pot experiments were conducted for the purposes of preliminarily discussing the potential of using an energy plant, sweet sorghum (Sorghum bicolor (L.) Moench), to repair petroleum-polluted salinized soils and obtain associated varieties with excellent remediation performance. The emergence rate, plant height and biomass of different varieties were measured to explore the performance of plants under petroleum pollution, and the removal of petroleum hydrocarbons in soil with candidate varieties was also studied. The results showed that the emergence rate of 24 of the 28 varieties were not reduced by the addition of 1.0 × 104 mg/kg petroleum in soils with a salinity of 0.31%. After a 40-day treatment in salinized soil with petroleum additions of 1.0 × 104 mg/kg, 4 potential well-performed varieties including Zhong Ketian No. 438, Ke Tian No. 24, Ke Tian No. 21 (KT21) and Ke Tian No. 6 with a plant height of >40 cm and dry weight of >4 g were screened. Obvious removal of petroleum hydrocarbons in the salinized soils planted with the four varieties were observed. Compared with the treatment without plants, the residual petroleum hydrocarbon concentrations in soils planted with KT21 decreased by 69.3%, 46.3%, 56.5%, 50.9% and 41.4%, for the additions of 0, 0.5 × 104, 1.0 × 104, 1.5 × 104 and 2.0 × 104 mg/kg, respectively. In general, KT21 had the best performance and application potential to remediate petroleum-polluted salinized soil.

Bacillus thuringiensis A1 improve phenol tolerance and phytoextraction by Acorus calamus L.

Phenol, as a very toxic pollutant, exists widely in rivers in China. To explore the effect of bacterial augmentation on phytoremediation of phenol by Acorus calamus L., some plant growth and physiological parameters and percent removal of phenol were determined in hydroponics containing phenol with addition of Bacillus thuringiensis A1. The A. calamus L. and B. thuringiensis A1 consortium increased the growth rate of plant height, chlorophyll content, the activity of superoxide dismutase (SOD) and peroxidase (POD) in A. calamus L. 10.00-36.54%, 0.62 - 22.15%, 3.94 - 11.25% and 1.37-10.50% respectively compared with single plant treatments at same phenol concentrations. However, the addition of B. thuringiensis A1 decreased the content of malondialdehyde (MDA) and relative electrical conductivity (REC) in A. calamus L. 12.99-23.66% and 8.38-29.98% respectively compared with single plant treatments. The removal efficiency of phenol (increased from 1.56% to 13.78%) by the A. calamus L. and B. thuringiensis A1 consortium was higher than the removal efficiency of phenol of the independent A. calamus L. system. In conclusion, the addition of B. thuringiensis A1 alleviated phenol stress to A. calamus L and enhanced phenol removal due to phenol removal by bacterial augmentation.Novelty statementThe addition of B. thuringiensis A1 alleviated phenol stress to A. calamus L. and enhanced phenol removal due to phenol removal by bacterial augmentation.

The photosynthetic physiological response and purification effect of Salix babylonica to 2, 4-dinitrophenol wastewater.

Phytoremediation technology based on living green plants would clean up water pollution. Through hydroponic experiment, the effects of different concentration of 2, 4-dinitrophenol (2, 4-DNP) on the photosynthetic and chlorophyll fluorescence parameters of Salix babylonica, and the absorption and purification effect of S. babylonica on 2, 4-DNP were measured to explore the tolerance of S. babylonica to 2, 4-DNP and the feasibility to purify dinitrophenol waste water by it. The biomass, actual photochemical efficiency (PSII), net photosynthetic rate (Pn), photochemical quenching coefficient (qP), stomatal conductance (Gs), transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm) and chlorophyll content of the S. babylonica showed downward trend with the increasing exposure concentrations of 2,4-DNP, but the intercellular CO2 concentration (Ci) appeared upward trend. Non-photochemical quenching coefficient (NPQ) increased at 5 mg L-1, then declined with the increase concentrations of 2, 4-DNP. In addition, the percent removal of 2, 4-DNP in 20 mg L-1 waste water was 91.4%. In conclusion, 2, 4-DNP significantly inhibits Pn of S. babylonica and the reduction of Pn was caused by decreasing Gs, carboxylation efficiency and chlorophyll content. When the concentration of 2, 4-DNP is not more than 20 mg L-1, S. babylonica can remove 2, 4-DNP efficiently.

Phytoremediation of aniline by Salix babylonica cuttings: Removal, accumulation, and photosynthetic response.

Aniline, a synthetic compound widely used in industrial and pesticide production, is a potential environmental pollutant. The removal of aniline is extremely important to minimize threats to human health and the surrounding environment. The objectives of this study were to investigate the removal efficiency and physiological response of Salix. babylonica cuttings to aniline pollution. Photosynthesis, chlorophyll fluorescence, spectral reflectance and the concentration of aniline in leaves, stems and roots were analysed. The experiment showed that S. babylonica has a strong removal effect on aniline wastewater. Cuttings from S. babylonica stems and roots played an important role in accumulating aniline. However, this increase in aniline concentration was dose dependent and was not always linear. With increasing aniline concentration in S. babylonica was increasingly stressed, with negative impacts on photosynthesis, chlorophyll fluorescence and spectral reflectance index in S. babylonica leaves. These results indicate that non-stomatal limitations are the main reason for the reduction in Pn in S. babylonica leaves due to chlorophyll structure destruction under aniline stress. In addition, aniline concentrations result in an unbalanced distribution of excitation energy between the two light systems, thereby hindering photosynthetic electron transfer and restricting the efficient operation of photosynthesis. Salix babylonica can endure moderate concentrations of aniline and has potential for the phyto-management of aniline-polluted wastewater, although further studies are needed using polluted wastewater.

[Dynamic evaluation and driving forces of ecosystem services in Quanzhou bay estuary wetland, China]. / 泉州湾河口湿地生态系统服务价值的动态评价及驱动力分析.

Ecosystem service value (ESV) in 1997, 2005, 2013 and 2015 of Quanzhou Bay estuary wetland was evaluated dynamicly by market value, alternative value and opportunity cost methods, combined with classification of service indicators and deduplicate computing. The main driving forces for the changes of ESV and the pathway and intensity of their actions were identified using stepwise regression and path analysis methods. The results showed that the main ecosystem services of Quanzhou Bay estuary wetland were flood regulation, climate regulation, and food supply, which were directly driven by water supply, mariculture carrying capacity, and gross value of the regional production. Other drivers exerted indirect effect on the changes of main ESVs.

Applications of fractional lower order S transform time frequency filtering algorithm to machine fault diagnosis.

Stockwell transform(ST) time-frequency representation(ST-TFR) is a time frequency analysis method which combines short time Fourier transform with wavelet transform, and ST time frequency filtering(ST-TFF) method which takes advantage of time-frequency localized spectra can separate the signals from Gaussian noise. The ST-TFR and ST-TFF methods are used to analyze the fault signals, which is reasonable and effective in general Gaussian noise cases. However, it is proved that the mechanical bearing fault signal belongs to Alpha(α) stable distribution process(1 < α < 2) in this paper, even the noise also is α stable distribution in some special cases. The performance of ST-TFR method will degrade under α stable distribution noise environment, following the ST-TFF method fail. Hence, a new fractional lower order ST time frequency representation(FLOST-TFR) method employing fractional lower order moment and ST and inverse FLOST(IFLOST) are proposed in this paper. A new FLOST time frequency filtering(FLOST-TFF) algorithm based on FLOST-TFR method and IFLOST is also proposed, whose simplified method is presented in this paper. The discrete implementation of FLOST-TFF algorithm is deduced, and relevant steps are summarized. Simulation results demonstrate that FLOST-TFR algorithm is obviously better than the existing ST-TFR algorithm under α stable distribution noise, which can work better under Gaussian noise environment, and is robust. The FLOST-TFF method can effectively filter out α stable distribution noise, and restore the original signal. The performance of FLOST-TFF algorithm is better than the ST-TFF method, employing which mixed MSEs are smaller when α and generalized signal noise ratio(GSNR) change. Finally, the FLOST-TFR and FLOST-TFF methods are applied to analyze the outer race fault signal and extract their fault features under α stable distribution noise, where excellent performances can be shown.