浙江农林大学

Refrigeration is widely used to preserve sweet corn (Zea mays var. saccharata); however, quality deterioration driven by metabolic imbalance and oxidative stress still constrains its storage potential. In this study, treatment with 50 μmol·L−1 melatonin (MT) or 1% tea polyphenols (TPs) effectively delayed quality deterioration of sweet corn during storage at 4 °C. Both treatments alleviated kernel shrinkage and browning, reduced weight loss, and maintained higher total soluble solids. They commonly promoted starch degradation and sustained soluble sugar availability during storage, while differing in sucrose regulation. In parallel, phenylpropanoid metabolism was modulated under both treatments, which was associated with restrained phenolic oxidation and delayed browning development. Both treatments altered flavonoid metabolism, increased total flavonoid content and several individual flavonoids, enhanced antioxidant enzyme activities, and reduced membrane lipid peroxidation, but MT elicited broader transcriptional regulation across the flavonoid pathway, whereas TPs showed a more selective transcriptional response. MT predominantly activated glutathione-associated detoxification pathways through coordinated regulation of glutathione S-transferase–related genes and glutathione metabolism, thereby supporting redox homeostasis during storage. By contrast, TPs mainly suppressed α-linolenic acid metabolism and jasmonic acid biosynthesis-associated processes via downregulation of LOX- and PLA-related genes and reduced LOX activity, thereby attenuating senescence-associated signaling and lipid oxidation. Overall, MT and TPs extend the storage life of sweet corn through distinct antioxidant strategies, targeting redox homeostasis and senescence regulation, respectively, and offering practical options for improving postharvest preservation under refrigerated conditions.

Soil microbial carbon use efficiency (CUE) plays a critical role in carbon (C) cycling and ecosystem functioning, yet its response to nitrogen (N) deposition remains poorly understood, particularly in planted forests. This study investigates how N addition affects microbial CUE and its underlying mechanisms in Populus deltoides plantations in coastal eastern China. Using a long-term field experiment with five levels of N addition (0–30 g N·m−2·yr−1), we measured microbial CUE, soil chemical properties, enzyme activities, and microbial community composition from 2018 to 2020. We found that N addition significantly reduced microbial CUE, primarily through N-induced stoichiometric imbalances and soil acidification. Excess N increased available N and decreased the DOC:AN ratio, driving microbial carbon limitation and reducing metabolic efficiency. Furthermore, N addition suppressed bacterial diversity and shifted microbial communities toward taxa with lower CUE. Model selection identified soil pH, available N, and DOC:AN as key predictors of microbial CUE. These findings highlight the dominant role of soil environmental factors—particularly nutrient stoichiometry and pH—in regulating microbial CUE. Our results suggest that excessive N deposition may compromise soil C sequestration in poplar plantations by altering microbial resource allocation and reducing microbial metabolic efficiency. Managing nutrient balance and maintaining microbial diversity are thus critical for sustaining soil health and carbon storage in forest ecosystems under increasing N deposition.

The temperature sensitivity (Q10) of soil microbial respiration (Rs) is a critical parameter for predicting the response of microbially mediated decomposition of global soil organic carbon (SOC) to climate change. However, the variations in Q10 across horizontal and vertical spatial gradients remain contentious. In this study, we conducted a simulated soil warming incubation experiment across temperature gradients of 5 °C, 15 °C, 25 °C, and 35 °C using soils collected from the southern subtropical forest (SSF), mid-subtropical forest (MSF) and temperate forest (TF) in China. Soil samples were obtained from four depth intervals along a 60 cm soil profile: 0–15 cm, 15–30 cm, 30–45 cm, and 45–60 cm. We measured soil microbial respiration, SOC fractions, soil chemical properties, microbial community structure and activity. Q10 values were calculated, and the underlying mechanistic relationships among these variables were examined. Significant spatial variations in Q10 were observed (P < 0.05): (1) in the 30–60 cm soil layers, Q10 values in TF were significantly higher than those in SSF and MSF; (2) with in SSF, Q10 in the topsoil (0–15 cm) was markedly greater than that in the deep soil (45–60 cm). Horizontally, the higher Q10 values in TF appear to be influenced with higher-quality carbon substrates, a greater abundance of K-strategies microbial taxa, higher microbial activity and prolonged exposure to low temperatures. Vertically, in the SSF, the higher Q10 in topsoil was primarily attributed to higher SOC content, the presence of more labile carbon substrates and enhanced microbial activity. These findings underscore the important roles of carbon quality, microbial life-history strategies (K-strategies) and microbial activity in mediating the Q10 of Rs, especially in deep soils which are easily ignored. Based on these findings, it can be predicted that under global warming scenarios, temperate forests may experience accelerated SOC decomposition at horizontal spatial scales, especially in deeper soil layers. In subtropical forests, topsoil may exhibit more rapid carbon loss along vertical gradients.

Understanding the effects of fires on soil fauna is critical, given their central role in belowground biodiversity and ecosystem functioning, especially in the current context of increasingly intense wildfires around the world. However, the impacts of fires on soil fauna communities on a global scale are still poorly understood. Here, we conducted a global meta-analysis with 4578 paired observations to evaluate the effects of fire on soil fauna density, biomass, and diversity. Results showed that (1) fire significantly decreased soil fauna density, taxonomic richness, and Shannon Wiener diversity index by 41, 33, and 48

In this document we carry out the cocrystallization of the both diacids, 1,5-naphthalenedisulfonic acid (H2nds) and the 3-nitrophthalic acid (H2npta), with the picolinic acid (pa), and two unpublished hydrate multicomponent crystalline phases are successfully grown by the solution controlled ventilation technique. Characterizations by single crystal X-ray diffraction (SCXRD), Fourier transform Infrared (FTIR) spectrum, and melting points (Tmp) measurement display that the both new systems are produced, embodying a 2:1 dihydrate salt of the pa and H2nds, and a 1:1 pa-H2npta monohydrate cocrystal. To unveil the associates within the crystal stackings of the both complexes, Hirshfeld surface analysis (HSA) is conducted. Through the supramolecular synthons investigation the structural and supramolecular natures are uncovered in full detail. Both structures have the hetero supramolecular synthons. Investigation on the crystal packings unveils that the N–H⋯O/O–H⋯O H bonds are included within both the complexes. Salt 1 shows the additional N–H⋯S/O–H⋯S H-bonds. Apart from the classical H-bonds, the auxiliary linkages of the CH–O, CH–π, O–O, C–π and O–π also play the key roles in the spatial expandings. The HSA adds the additional sights into the popularity of the diverse short noncovalent linkages within both the crystal structures. The both systems are decorated by the R_1^2 (3), R_2^2 (12), R_3^2 (7), R_3^2 (13), R_3^3 (9), R_3^3 (11), R_3^3 (16), R_4^3 (14), R_4^4 (16), R_4^4 (18), R_4^4 (20), R_5^4 (22), R_5^5 (32) and R_6^6 (33) synthons, but both do not share the identical one. In conclusion, the 2D sheet/3D motifs are erected through using the broad type of the non-covalent connections.