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Ginseng, from the roots of Panax ginseng C. A. Meyer, is a widely used herbal medicine in Asian countries, known for its excellent therapeutic properties. The growth of P. ginseng is depend on specific and strict environments, with a preference for wetness but intolerance for flooding. Under excessive soil moisture, some irregular rust-like substances are deposited on the root epidermis, causing ginseng rusty symptoms (GRS). This condition leads to a significant reduce in yield and quality, resulting in substantial economic loses. However, there is less knowledge on the cause of GRS and there are no effective treatments available for its treatment once it occurs. Unsuitable environments lead to the generation of large amounts of reactive oxygen species (ROS). We investigated the key indicators associated with the stress response during different physiological stages of GRS development. We observed a significant change in ROS level, MDA contents, antioxidant enzymes activities, and non-enzymatic antioxidants contents prior to the GRS. Through the analysis of soil features with an abundance of moisture, we further determined the source of ROS. The levels of nitrate reductase (NR) and nitric oxide synthase (NOS) activities in the inter-root soil of ginseng with GRS were significantly elevated compared to those of healthy ginseng. These enzymes boost nitric oxide (NO) levels, which in turn showed a favorable correlation with the GRS. The activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase first rose and then decreased as GRS developed. Excess soil moisture causes a decrease in oxygen levels. This activated NR and NOS in the soil, resulting in a production of excess NO. The NO then diffused into the ginseng root and triggered a burst of ROS through NADPH located on the cell membrane. Additionally, Fe2+ in soil was oxidized to red Fe3+, and finally led to GRS. This conclusion was also verified by the Sodium Nitroprusside (SNP), a precursor compound producing NO. The presence of NO from NR and NOS in water-saturated soil is responsible for the generation of ROS. Among these, NO is the main component that contribute to the occurrence of GRS. [ABSTRACT FROM AUTHOR]

Vanadium redox flow batteries (VRFBs) are prospective energy-storage medium owing to their flexible design and long lifetime. However, the problem of sluggish negative electrode dynamics of VRFBs has become a great resistance to their large-scale commercial applications. To solve this problem, we employed a facile and cost-effective approach to synthesize NiO/rGO composites using hydrothermal and calcination processes. The NiO/rGO nanocatalysts were evenly applied onto the heat-treated graphite felt (HGF) to prepare a high-performance negative electrode for VRFBs. This coating process was achieved using an ultrasonic spraying system, resulting in NiO/rGO-HGF. The NiO/rGO electrocatalysts provided enhanced adsorption characteristics of vanadium ions and sufficient redox-reactive sites, which improved electrochemical performance (9.41% higher energy efficiency of NiO/rGO-HGF compared with HGF at 160 mA cm−2) and high cycle stability (84.7% electrolyte capacity after 100 cycles) of the VRFB cells. In conclusion, our work with the NiO/rGO-HGF anode represents a promising direction for the development of highly efficient and stable VRFB anodes for broadening commercial applications. [ABSTRACT FROM AUTHOR]

The ecological significance of secondary metabolites is to improve the adaptive ability of plants. Secondary metabolites, usually medicinal ingredients, are triggered by unsuitable environment, thus the quality of medicinal materials under adversity being better. The quality of the cultivated was heavily declined due to its good conditions. Radix Saposhnikoviae, the dried root of Saposhnikovia divaricata (Turcz.) Schischk., is one of the most common botanicals in Asian countries, now basically comes from cultivation, resulting in the market price being only 1/10 to 1/3 of its wild counterpart, so improving the quality of cultivated Radix Saposhnikoviae is of urgency. Nitric oxide (NO) plays a crucial role in generating reactive oxygen species and modifying the secondary metabolism of plants. This study aims to enhance the quality of cultivated Radix Saposhnikoviae by supplementing exogenous NO. To achieve this, sodium nitroprusside (SNP) was utilized as an NO provider and applied to fresh roots of S. divaricata at concentrations of 0.03, 0.1, 0.5, and 1.0 mmol/L. This study measured parameters including the activities of antioxidant enzymes, secondary metabolite synthesis enzymes such as phenylalanine ammonia-lyase (PAL), 1-aminocyclopropane-1-carboxylic acid (ACC), and chalcone synthase (CHS), as well as the contents of NO, superoxide radicals (O2·−), hydrogen peroxide (H2O2), malondialdehyde (MDA), and four secondary metabolites. The quality of Radix Saposhnikoviae was evaluated with antipyretic, analgesic, anti-inflammatory effects, and inflammatory factors. As a result, the NO contents in the fresh roots were significantly increased under SNP, which led to a significant increase of O2·−, H2O2, and MDA. The activities of important antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), were found to increase as well, with their peak levels observed on the 2nd and 3rd days. PAL, ACC, and CHS activities were also significantly enhanced, resulting in the increased secondary metabolite contents of Radix saposhnikoviae in all groups, especially the 0.5 mmol/L SNP. The four active ingredients, prim-O-glucosylcimifugin, cimifugin, 4′-O-β-d-glucosyl-5-O-methylvisamminol, and sec-O-glucosylhamaudol, increased by 88.3%,325.0%, 55.4%, and 283.8%, respectively, on the 3rd day. The pharmaceutical effects of Radix Saposhnikoviae under 0.5 mmol/L SNP were significantly enhanced. Exogenous SNP can induce the physiological response of S. divaricata under adverse conditions and significantly improve the quality of Radix Saposhnikoviae. [ABSTRACT FROM AUTHOR]

Root branching and mycorrhizal symbioses are two major mechanisms for soil resource acquisition by trees. Understanding the relationship between these two mechanisms and their responses to varied environmental conditions is crucial for predicting the responses of foraging strategies of roots to environmental changes. This study was conducted in 11 Chinese fir (Cunninghamia lanceolata) plantations distributed in different environmental conditions in Subtropical China to assess the relationship between root tip traits related to nutrient foraging (branching ratio of 1st-order roots to 2nd-order roots, arbuscular mycorrhizal (AM) colonization) and their environmental variables, including mean annual precipitation (MAP), mean annual temperature (MAT), soil C, soil N, soil P, and soil pH. Root branching was more sensitive to environmental conditions than mycorrhizal symbioses. The branching ratio and AM colonization of Chinese fir were significantly related to several environmental variables. The branching ratios were positively correlated with MAT, but negatively correlated with soil C, soil N, and soil pH (P < 0.05), suggesting that harsh environmental conditions can promote absorptive root branching. To our surprise, the AM colonization of absorptive roots was not as sensitive to environmental factors as branching ratio. However, the AM colonization of absorptive roots was positively correlated with soil pH (P < 0.1), indicating that soil acidity controls mycorrhizal symbioses. Moreover, the branching ratio was significantly negatively correlated with AM colonization (P < 0.05). Our results confirmed that environmental conditions significantly regulate fine root branching and its mycorrhizal symbioses, but with different controlling variables. The negatively correlated relationship of branching ratio and AM colonization shows that environmental factors regulate absorptive root traits in different ways. [ABSTRACT FROM AUTHOR]