Melatonin plays an important role in numerous vital life processes of animals and has recently captured the interests of plant biologists because of its potent role in plants. As well as its possible contribution to photoperiodic processes, melatonin is believed to act as a growth regulator and/or as a direct free radical scavenger/indirect antioxidant. However, identifying a precise concentration of melatonin with an optimum nitrogen level for a particular application method to improve plant growth requires identification and clarification. This work establishes inimitable findings by optimizing the application of melatonin with an optimum level of nitrogen, alleviating the detrimental effects of drought stress in maize seedlings. Maize seedlings were subjected to drought stress of 40–45% field capacity (FC) at the five-leaf stage, followed by a soil drenching of melatonin 100 µM and three nitrogen levels (200, 250, and 300 kg ha−1) to consider the changes in maize seedling growth. Our results showed that drought stress significantly inhibited the physiological and biochemical parameters of maize seedlings. However, the application of melatonin with nitrogen remarkably improved the plant growth attributes, chlorophyll pigments, fluorescence, and gas exchange parameters. Moreover, melatonin and nitrogen application profoundly reduced the reactive oxygen species (ROS) accumulation by increasing maize antioxidant and nitrogen metabolism enzyme activities under drought-stress conditions. It was concluded that the mitigating potential of 100 µM melatonin with an optimum level of nitrogen (250 kg N ha−1) improves the plant growth, photosynthetic efficiency, and enzymatic activity of maize seedling under drought-stress conditions.

Microcystis aeruginosa blooms are a worldwide serious environmental problem and bloom control with bacteria is promising. In this study, a Bacillus licheniformis strain Sp34 with potent algicidal and inhibitory effects on the microcystins synthesis against fast‐growing M. aeruginosa was isolated from Dianchi Lake. Sp34 killed the bloom‐causing algal strain M. aeruginosa DCM4 of Dianchi Lake with an initial Chlorophyll‐a concentration of 2.0 mg/L at a cell density of no less than 1.35 × 105 CFU/ml. It can also efficiently kill some other harmful algal species, such as M. wesenbergii and Phormidium sp. The algicidal activity of Sp34 relied on the release of algicidal substances, which had good heat (−20°C to 121°C) and acid–base (pH 3–11) resistance. In addition, the high algicidal activity depended on the good growth of algae indicated by the significantly positive correlations between algal growth and algicidal ratio (p < .001). The algicidal effect of Sp34 involved causing oxidative stress, lipid peroxidation, and morphological injury of algal cells, along with DNA damage and dysfunction of DNA‐repair function, weakening the photosynthesis system, and inhibiting microcystin synthesis. In general, Sp34 can kill fast‐growing M. aeruginosa and inhibit algal microcystin synthesis efficiently, so, it is a promising biocontrol agent to mitigate cyanobacterial blooms.

Oxidative stress has been proven as one of the most critical regulatory mechanisms involved in fine Particulate Matter- (PM2.5-) mediated toxicity. For a better understanding of the underlying mechanisms that enable oxidative stress to participate in PM2.5-induced toxic effects, the current study explored the effects of oxidative stress induced by PM2.5 on UPR and lifespan in C. elegans. The results implicated that PM2.5 exposure induced oxidative stress response, enhanced metabolic enzyme activity, activated UPR, and shortened the lifespan of C. elegans. Antioxidant N-acetylcysteine (NAC) could suppress the UPR through reducing the oxidative stress; both the antioxidant NAC and UPR inhibitor 4-phenylbutyric acid (4-PBA) could rescue the lifespan attenuation caused by PM2.5, indicating that the antioxidant and moderate proteostasis contribute to the homeostasis and adaptation to oxidative stress induced by PM2.5.

Soil sodicity and salinization is a major issues concerning agricultural production in northeast China. The effects of six treatments—no tillage (NT), no tillage and subsoiling (NTS), rotary and ridge tillage (RT), rotary and ridge tillage and subsoiling (RTS), rotary and flat tillage (FT), and rotary and flat tillage and subsoiling (FTS)—on soil physical and chemical properties and yields were compared from 2016 to 2018. The results showed that compared with the RT treatment, which is the traditional tillage method in this area, and the FT treatment, the NT treatment increased the soil water content (SWC) during the first‐leaf growth stage (V1). The use of subsoiling increased the average daily temperature and the soil thermal time (TTsoil). Subsoiling contributed to the growth and development of deep roots and increased leaf area index (LAI) to intercept more radiation. The NTS treatment increased grain yield of maize (Zea mays L.) by 2.7–15.2%, nitrogen use efficiency (NUE) by 4.2–14.4%, and water use efficiency (WUE) by 5.4–16.5% compared with RT. In conclusion, NTS soil management practices appear to be a sustainable approach to farming in the semiarid region of the Songnen Plain.

Changes in agricultural management can potentially change the rate of C sequestration. The rain-fed agricultural areas of the Songnen Plain are China's main grain-producing areas, and this region has a temperate monsoon climate with an annual average temperature of 2.0−5.6 • C, annual average rainfall of 350−460 mm, and annual evaporation of 1,000−1,600 mm. In a short-term experiment (2014−2019), the effects of no-tillage (NT), no-tillage and subsoiling (NTS), rotary and ridge tillage (RT), rotary and ridge tillage and subsoiling (RTS), rotary and flatten tillage (FT), and rotary and flatten tillage and subsoiling (FTS) on alkaline meadow soil in the surface 0−30 cm of soil was investigated. Measurements after 5 yr showed that, under NT at 0-to 30-cm depth, the bulk density of soil, soil water content, and soil nutrient content significantly increased when compared with RT and FT. Soil organic carbon (SOC) stocks at 0−30 cm were increased by 2.23% (0.99 Mg ha −1) under NT, and the annual accumulation rate of SOC stocks under NT reached 0.20 Mg ha −1. Under RT and FT, SOC stocks decreased by 2.11% (0.94 Mg ha −1) and 2.18% (0.97 Mg ha −1), respectively, when compared with the beginning of the experiment. This indicates that NT, compared with RT and FT, reduces soil C loss and is conducive to the C sequestration. 1 INTRODUCTION Soil organic matter is an important component of soil health and influences nutrient cycling, plant health, and greenhouse gas emissions (Hoyle, Barton, Stefanova, & Murphy, 2016; Jin et al., 2018). However, minor changes in soil organic carbon (SOC) stocks could greatly affect atmospheric CO 2 concentrations (Wang et al., 2014).