Exogenous DCPTA Increases the Tolerance of Maize Seedlings to PEG-Simulated Drought by Regulating Nitrogen Metabolism-Related Enzymes

2-(3,4-Dichlorophenoxy) triethylamine (DCPTA) regulates plant development; however, the molecular basis of this regulation is poorly understood. In this study, RNA sequencing (RNA-seq) analysis and physiological indexes of maize seedlings (three-leaf stage) treated with 15% polyethylene glycol (PEG) with/without DCPTA were investigated to explore the possible mechanism of exogenous DCPTA-improved drought tolerance. In the library pair comparisons of DCPTA vs. the control, PEG vs. the control, and PEG + DCPTA vs. PEG, totals of 19, 38 and 20 differentially expressed genes (DEGs) were classified as being involved in metabolic processes, respectively; totals of 5, 11, and 6 DEGs were enriched in the nitrogen (N) metabolic pathway, respectively. The genes encoding nicotinamide adenine dinucleotide-nitrate reductase (NADH-NR), ferredoxin-nitrite reductase (Fd-NiR), reduced ferredoxin- glutamate synthase (Fd-GOGAT), and chloroplastic glutamine synthetase (GS 2) were common in response to PEG-simulated drought stress with/without DCPTA treatment. Moreover, DCPTA maintained stable gene relative expression levels and protein abundances of NADH-NR, Fd-NiR, GS2, and Fd-GOGAT. Moreover, exogenous DCPTA partially mitigated PEG-simulated drought-induced reductions in the enzymatic activities of NR, nitrite reductase (NiR), glutamine synthase (GS), glutamine oxoglutarate aminotransferase (GOGAT), and transaminase, as well as in the contents of nitrate (NO3−), nitrite (NO2−) and soluble proteins and increases in the contents of ammonium (NH4+) and free amino acids. Together, our results indicate that exogenous DCPTA improved plant growth and drought tolerance by regulating N-mechanism enzymatic activities involved in transcription and enzymatic protein synthesis

Case Investigation on the Influence of In‐Snow Particles' Size and Composition on the Snow Light Absorption and Albedo

Abstract The snow physical parameters are closely related to the sizes, shapes, and chemical composition of light‐absorbing particles (LAPs). By utilizing a computer‐controlled scanning electron microscope software called IntelliSEM‐EPASTM, we first report the measured size‐resolved concentration of soot, dust, and fly ash particles in fresh (wet) and aged (dry deposition) snow samples collected at an industrial city in China during and after a snowfall at intervals of 6–8 days. Due to wet scavenging by seasonal snow, soot and dust particles in snow are absorbed by 69.7% and 30.3% at wavelengths of 550 nm, lowering snow albedo by 0.0089 and 0.0039, respectively. Soot particle size increases slightly during dry deposition, whereas size‐resolved mineral dust does not undergo a significant shift in particle size. These results indicate the essentiality to involve the effects of accurate size and composition of in‐snow LAPs for a better assessment of snow light absorption and reflectance

Effect of Cold Plasma Treatment on the Quality of Fresh-Cut Hami Melons during Chilling Storage

Cold plasma (CP) is an alternative to traditional thermal sterilization techniques. This study aimed to investigate the preservation effects of CP treatment at 120 kV and 130 Hz for 150 s on fresh-cut Hami melons during storage at 4 °C for 8 d. There was no significant difference in the pH, color, firmness, and soluble solids content of the two groups during 0–4 days of storage. After CP treatment, the enzyme activities, total viable count (TVC), and values of the electronic nose (E-nose) changed. During storage, the increase in polyphenol oxidase (PPO) and peroxidase (POD) activities was inhibited by CP treatment. Initially, CP treatment yielded a 1.06 log reduction in total viable count (TVC). During storage, the TVC of the CP-treated group was significantly lower than that of the untreated group. CP treatment affected the E-nose values related to ketones, terpenes, polar, aromatic, and sulphur compounds. This study indicated that high-voltage and short-time CP treatment can extend the shelf-life of fresh-cut Hami melons by inhibiting oxidation and reducing microbial contamination without negative effects on physical quality

Method of Entry Layout under Synergistic Effects of Abutment Stress and Dynamic Stress

In underground mining engineering, rocks around the entry are always subjected to large plastic deformation disasters, such as supporting body failure, roof rock collapse, and even rock burst under abutment stress and dynamic stress. To improve the stability of these rocks, the entry layout under abutment stress and dynamic stress (ELAD) method was put forward to protect the entry from high abutment stress and dynamic stress. Dynamic disturbance intensity (DDI) was determined as the key evaluation index in ELAD, which was divided into “Slightly Disturbed Type,” “Moderately Disturbed Type,” and “Violent Impact Type” by the dynamic disturbance threshold (DDT) and dynamic large-deformation threshold (DLT). The established servo calculation algorithm was applied into a dynamic and static numerical analysis model with FLAC3D500 software for the solving of DDT and DLT by the method of zero growth DDI of plastic failure zone and the engineering-permitted limitation deformation. This model was validated by comparing the displacement of entry with the measured results in the field. The model results validated that the entry should keep away from the dynamic stress of Violent Impact Type firstly and then be arranged in the zone where the dynamic stress belongs to Slightly Disturbed Type. DDT increases linearly and DLT decreases with a power function as the increasing of the abutment stress. ELAD method is reliable to protect this kind of underground entry and its applicability will be improved by the support resistance by comparing the results from ELAD with those from the widely used methods for field investigation discussion. The analysis procedure can be repeatable and necessary since the rock and coal materials may be different in geological and engineering conditions

Unprecedented snow darkening and melting in New Zealand due to 2019–2020 Australian wildfires

Wildfire events have recently shown a rapid increase in frequency and scale due to the warmer present-day climate; however, their potential effects on the cryosphere are difficult to assess. Catastrophic wildfires in Australia during 2019–2020 emitted large amounts of light-absorbing particles (LAPs) to the atmosphere. Satellite observations indicate that these LAPs caused unprecedented snow-darkening of glaciers in New Zealand through long-range transport and deposition, with their effects lasting for up to three months in January–March 2020, influencing >90% of total glacier/snow and leading to a mean broadband snow-reflectance reduction of 0.08 ± 0.03. This snow darkening accelerated snowmelt by ~0.41 ± 0.2 cm day–1 during the southern summer, equivalent to that caused by a ~1.8 °C increase in air temperature. This indicates the significant impact of the 2019–2020 Australian wildfires on the hydrologic cycle in New Zealand, exceeding that of the local climate warming of ~1.5 °C since the preindustrial period. Wildfire-induced snow darkening is not limited to New Zealand. Future projections of wildfire incidence indicate widespread effects of snow darkening on the global cryosphere

Historical Changes of Black Carbon in Snow and Its Radiative Forcing in CMIP6 Models

Black carbon in snow (BCS) has a significant impact on global climate and is an important component of Earth system modeling. Here, we provide a comprehensive evaluation of BCS simulations in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and its radiative forcing on a global scale. Overall, the multi-model mean generally captures the characteristics of BCS spatial patterns, with maximum concentrations in East Asia and the Tibetan Plateau (~120 ng·g−1), and the lowest in Antarctica (~0.05 ng·g−1). The BCS concentrations in all CMIP6 multi-model mean and individual models generally exhibit a temporally increasing trend globally, with particularly large increases after the 1940s. In terms of seasonal cycles, individual models are generally consistent in most regions. Globally, BCS concentrations are highest around January and lowest in September. The albedo reduction in the Tibetan Plateau and East Asia simulated by the CMIP6 multi-model mean reached ~0.06 in 2014 and may influence climate more than expected

Historical Changes of Black Carbon in Snow and Its Radiative Forcing in CMIP6 Models

Black carbon in snow (BCS) has a significant impact on global climate and is an important component of Earth system modeling. Here, we provide a comprehensive evaluation of BCS simulations in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and its radiative forcing on a global scale. Overall, the multi-model mean generally captures the characteristics of BCS spatial patterns, with maximum concentrations in East Asia and the Tibetan Plateau (~120 ng·g−1), and the lowest in Antarctica (~0.05 ng·g−1). The BCS concentrations in all CMIP6 multi-model mean and individual models generally exhibit a temporally increasing trend globally, with particularly large increases after the 1940s. In terms of seasonal cycles, individual models are generally consistent in most regions. Globally, BCS concentrations are highest around January and lowest in September. The albedo reduction in the Tibetan Plateau and East Asia simulated by the CMIP6 multi-model mean reached ~0.06 in 2014 and may influence climate more than expected

Exogenous 2-(3,4-Dichlorophenoxy) triethylamine ameliorates the soil drought effect on nitrogen metabolism in maize during the pre-female inflorescence emergence stage

Abstract Background Nitrogen (N) metabolism plays an important role in plant drought tolerance. 2-(3,4-Dichlorophenoxy) triethylamine (DCPTA) regulates many aspects of plant development; however, the effects of DCPTA on soil drought tolerance are poorly understood, and the possible role of DCPTA on nitrogen metabolism has not yet been explored. Results In the present study, the effects of DCPTA on N metabolism in maize (Zea mays L.) under soil drought and rewatering conditions during the pre-female inflorescence emergence stage were investigated in 2016 and 2017. The results demonstrated that the foliar application of DCPTA (25 mg/L) significantly alleviated drought-induced decreases in maize yield, shoot and root relative growth rate (RGR), leaf relative water content (RWC), net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr), and nitrate (NO3 −), nitrite (NO2 −), soluble protein contents, and nitrate reductase (NR), nitrite reductase (NiR), isocitrate dehydrogenase (ICDH), alanine aminotransferase (AlaAT) and aspartate aminotransferase (AspAT) activities. In addition, the foliar application of DCPTA suppressed the increases of intercellular CO2 concentration (Ci), ammonium (NH4 +) and free amino acid contents, and the glutamate dehydrogenase (GDH) and protease activities of the maize. Simultaneously, under drought conditions, the DCPTA application improved the spatial and temporal distribution of roots, increased the root hydraulic conductivity (Lp), flow rate of root-bleeding sap and NO3 − delivery rates of the maize. Moreover, the DCPTA application protected the chloroplast structure from drought injury. Conclusions The data show, exogenous DCPTA mitigates the repressive effects of drought on N metabolism by maintained a stabilized supply of 2-oxoglutarate (2-OG) and reducing equivalents provided by photosynthesis via favorable leaf water status and chloroplast structure, and NO3 − uptake and long-distance transportation from the roots to the leaves via the production of excess roots, as a result, DCPTA application enhances drought tolerance during the pre-female inflorescence emergence stage of maize

Modulating the antioxidant system by exogenous 2-(3,4-dichlorophenoxy) triethylamine in maize seedlings exposed to polyethylene glycol-simulated drought stress.

Maize (Zea mays L.), an important agricultural crop, suffers from drought stress frequently during its growth period, thus leading to a decline in yield. 2-(3,4-Dichlorophenoxy) triethylamine (DCPTA) regulates many aspects of plant development; however, its effects on crop stress tolerance are poorly understood. We pre-treated maize seedlings by adding DCPTA to a hydroponic solution and then subjected the seedlings to a drought condition [15% polyethylene glycol (PEG)-6000 treatment]. The activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) were enhanced under drought stress and further enhanced by the DCPTA application. The activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and catalase (CAT) declined continuously under drought stress; however, the activities partially recovered with DCPTA application. Up-regulation of the activities and transcript levels of APX, GR, MDHAR and DHAR in the DCPTA treatments contributed to the increases in ascorbate (AsA) and glutathione (GSH) levels and inhibited the increased generation rate of superoxide anion radicals (O2·-), the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA), and the electrolyte leakage (EL) induced by drought. These results suggest that the enhanced antioxidant capacity induced by DCPTA application may represent an efficient mechanism for increasing the drought stress tolerance of maize seedlings