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Modeling stock returns and option pricing in the presence of jumps remains a central challenge in financial economics. This paper employs a novel score-driven GARCH-jump model to analyze SSE (Shanghai Stock Exchange) 50 ETF returns and option pricing. The main findings are as follows. First, we use 50 ETF spot returns to estimate conditional volatility and jump intensity, and find that the SDSDJ (score-driven separate dynamic jumps) model significantly outperforms conventional GARCH-jump models in model fitting. Second, we evaluate both in-sample and out-of-sample pricing performance using data from 50 ETF options, and find that the SDSDJ model achieves the lowest in-sample pricing error among all benchmarks, while its simplified variant—the SDJ (score-driven jumps) model—delivers the most accurate out-of-sample results. Third, the superior pricing performance of both models is robust across different levels of moneyness and DTM (days-to-maturity).

BackgroundThe growth of potato (Solanum tuberosum L.) is severely affected by the complex and variable soil environment, and film mulching has been widely used for potato growth in semiarid areas of western China. However, there are few studies on the effects of film mulching on soil quality and tuber yield in potato fields.MethodsThe effects of four mulching patterns (flat plot without film mulching, FP; flat plot with film mulching, FPM; ridge planting with half mulch, RPHM; ridge planting with full mulch, RPFM) on soil chemical and biological properties and potato tuber yield were investigated during two growing seasons (2018 and 2019) in the field.ResultsThe results showed that compared with FP, the mulching treatments significantly increased the tuber yield of potato, with an increase of 3.7–20.77% and 7.89–26.35% in 2018 and 2019, respectively, and the yield of RPFM was higher than that of other treatments. In both growing seasons, RPFM significantly increased the contents of alkali-hydrolyzed N and available P, and the activities of soil urease, catalase, alkaline phosphatase, and sucrase. Bacterial and actinomycete counts were significantly higher in RPFM than those in the other treatments. Furthermore, RPFM significantly increased large potatoes and decreased small potatoes. Pearson’s correlation analysis revealed that soil alkaline dissolved nitrogen and actinomycete populations were the main factors affecting potato yield formation.ConclusionsThese results indicate that RPFM can improve the soil environment and further increase potato tuber yield, which is a viable option for potato production in semiarid areas.

Malus halliana is an iron (Fe)-efficient apple rootstock growing in calcareous soil that shows obvious 'greenness' traits during Fe deficiency. Recent studies have shown that exogenous sugars can be involved in abiotic stress. To identify the key regulatory steps of chlorophyll (Chl) biosynthesis in M. halliana under Fe deficiency and to verify whether exogenous sucrose (Suc) is involved in Fe deficiency stress, we determined the contents of the Chl precursor and the expression of several Chl biosynthetic genes in M. halliana. The results showed that Fe deficiency caused a significant increase in the contents of protoporphyrin IX (Proto IX), Mg-protoporphyrin IX (Mg-Proto IX) and protochlorophyllide (Pchlide) in M. halliana compared to the Fe-sensitive rootstock Malus hupehensis. Quantitative real-time PCR (RT-qPCR) also showed that the expression of protoporphyrinogen oxidase (PPOX), which synthesizes Proto IX, was upregulated in M. halliana and downregulated in M. hupehensis under Fe deficiency. Exogenous Suc application prominently enhanced the contents of porphobilinogen (PBG) and the subsequent precursor, whereas it decreased the level of δ-aminolaevulinic acid (ALA), suggesting that the transformation from ALA to PBG was catalyzed in M. halliana. Additionally, the transcript level of δ-aminolevulinate acid dehydratase (ALAD) was noticeably upregulated after exogenous Suc treatment. This result, combined with the precursor contents, indicated that Suc accelerated the steps of Chl biosynthesis by modulating the ALAD gene. Therefore, we conclude that PPOX is the key regulatory gene of M. halliana in response to Fe deficiency. Exogenous Suc enhances M. halliana tolerance to Fe deficiency stress by regulating Chl biosynthesis.

BackgroundContinuous cropping can reduce soil quality and affect rhizosphere metabolism, ultimately reducing crop yield. Crop rotation can mitigate the damage caused by continuous cropping, but different crop rotation patterns respond differently to soil quality and rhizosphere metabolism. We investigated the effects of different cropping patterns on soil physicochemical properties, enzyme activities, microbial quantity, and rhizosphere metabolism of continuous potato cropping based on a long-term field study from 2018 to 2022. The experiment was set up with the following three treatments: potato (Solanum tuberosum L.)-potato-potato-potato-potato (CK), potato-potato-potato-pea (Pisum arvense L.)-potato (T1), and potato-potato-potato-faba bean (Vicia faba L.)-potato (T2).ResultsThe results showed that pea-potato rotation (T1) and faba bean-potato rotation (T2) significantly improved soil physicochemical properties and microbial quantity, enhanced enzyme activity, and increased yield by 21.19% and 28.38%, respectively, compared with the continuous potato crop. Non-targeted metabolomics analysis showed that the differential metabolites of pea-potato and faba bean-potato rotation were mainly nucleotides, organic acids and derivatives, and flavonoids compared to continuous potato cropping. These differential metabolites are mainly enriched in the ABC transporter, purine metabolism, pyrimidine metabolism, and phenylalanine metabolism pathways. Combined analyses showed that legume-potato rotations improved soil physicochemical properties, enzyme activities, and microbial quantity of continuous potato cropping, ultimately increasing tuber yields. In addition, correlation analyses showed that differential metabolites significantly enriched in purine and phenylalanine metabolism (l-Tyrosine, Trans-Cinnamic acid, Guanine, and Adenine) were also strongly associated with these measurements.ConclusionsTherefore, we conclude that legume-potato rotations modulate the abundance and function of rhizosphere metabolites and significantly alter the low molecular metabolite profile of the soil under continuous potato conditions. Some of these important metabolites may play a part in the cycling of nutrients in the soil, making its physicochemical properties and microbial quantity better, raising the activity of soil enzymes, and ultimately increasing the yield of potato tubers. The above results indicate that legume-potato rotation has a positive effect on continuous potato soils. It lays a solid foundation for revealing the complex molecular network and metabolic pathways of microbial communities in soil after legume crop rotation.

BackgroundCadmium (Cd) pollution has brought harm to the growth and development of potato. Glutathione (GSH) is an important antioxidant that may play an active role in the response of a potato to Cd stress. However, how GSH influences the effect of Cd on potatoes is unknown. In this study, we investigated the effects of exogenous GSH on the phenylpropanoid biosynthesis pathway and plant hormone signal transduction pathway in potatoes under Cd stress to explore new ideas for how potatoes respond to Cd stress. We cultured 21-day-old 'Atlantic’ plantlets in Murashige and Skoog (MS) medium supplemented with 500 μmol/L CdCl2 or 500 μmol/L CdCl2 + 400 μmol/L GSH. We then investigated the activities of key enzymes in the phenylpropanoid biosynthesis pathway, hormone levels, and the expression levels of related genes at different time points.ResultsAnalysis showed that 96 h of treatment with glutathione led to an increase in the expression levels of genes encoding phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD); an increase in the enzymic activities of PAL, CAD and POD; and an increase in the content of lignin. The content of lignin was positively correlated with the expression levels of several genes (PAL: PG0031457, CAD: PG0005359, POD: PG0011640 and PG0015106). In addition, the levels of Salicylic acid (SA) and Jasmonic acid (JA) increased significantly, the expression levels of the genes encoding transcription factor TGA (PG2023696), pathogenesis-related protein 1 (PR1) (PG0005111), and the transcription inhibitor Aux/IAA (PG0006093) all increased while the expression levels of jasmonate ZIM domain-containing protein (JAZ) (PG0004367), auxin influx carrier (AUX) (PG0006550) and auxin response factor (ARF) (PG0005794) all decreased. We also observed a reduction in the content of IAA.ConclusionExogenous GSH improved the tolerance of potato, Atlantic cv. to Cd stress by regulating the phenylpropanoid biosynthesis pathway and the plant hormone signal transduction pathway.HighlightsGlutathione affected the synthesis of phenylpropanoid in the potato.Glutathione affected the levels of plant hormone and the expression of related genes in potato.Glutathione enhanced the tolerance of potato to cadmium stress.Some genes play an important role in potato response to cadmium stress.

BackgroundHeat and drought stresses usually occur together in nature, and both are expected to increase in frequency and intensity as a result of climate change. The synergistic impacts of these compound climate extremes on potatoes are far from the effects of individual stresses. However, the dynamics of the effects of combined heat and drought stresses on potato physiology and biochemistry have yet to be thoroughly assessed. To elucidate this point, we set up a pot experiment using ‘Atlantic’ potato seedlings as test material. A total of six treatments were set up: CK (normal growth conditions: 21 ℃, 0 PEG), A1B1 (31 ℃, 20% PEG), A1B2 (31 ℃, 10% PEG), A1B3 (31 ℃, 0 PEG), A2B1 (21 ℃, 20% PEG), and A2B2 (21 ℃, 10% PEG), and 15 physiological indices were determined with the stress time of 0, 6, 12 and 18 days.ResultsAfter 18 days of stress, the phenotype of potato seedlings was significantly different. Compared with CK, the thickness of potato leaves and palisade tissue increased under heat and drought stress, and the combined stress reduced the photosynthetic efficiency of potato leaves. In all treatments except CK, the chlorophyll content decreased significantly, the antioxidant enzyme activity increased first and then decreased, and the relative conductivity and malondialdehyde content increased significantly. The heat and combined treatment made the content of the osmotic regulator first increase and then decrease, while the treatment of 21 ℃ had no significant change. According to the correlation, principal component and interaction analysis, both heat and drought treatment had significant effects on each index, and the longer the stress time, the greater the effect, and the effect of combined stress was greater than that of single stress. However, after 6 days of stress, the activity of antioxidant enzymes and the content of transparent regulatory substances increased.ConclusionsIn conclusion, potato can cope with heat, drought and combined stress by adjusting leaf tissue structure, antioxidant enzyme activity and osmotic regulatory substances in a short time.

BackgroundThe potato (Solanum tuberosum L.) is an important food crop in the alkaline soil area of northwest China. It is abundant in ascorbic acid (vitamin C), which facilitates iron absorption in the body. The large consumption of potato makes it a good food source of iron absorption for human body. However, iron deficiency in alkaline soil regions reduced chlorophyll synthesis in the leaves, resulting in lower photosynthesis and less sugar supply to the plant's healthy organs, significantly restricted crop development and yield, and inflicted major economic losses.MethodsIn this study, a 2-year (2020–2021) field trial was designed. Under foliar application of five different iron fertilizers: ferric sulfate [(Fe2(SO4)3], T1; ferrous sulfate (FeSO4·7H2O), T2; citric acid/ferric sulfate (CA/Fe2(SO4)3), T3; citric acid/ferrous sulfate (CA/FeSO4·7H2O), T4; ethylenediamine tetra acetic acid (EDTA-Fe·Na), T5, changes in potato plant photosynthesis were compared to no iron fertilization, CK conditions. The effects of various iron fertilizers on the yield, quality, and iron content of potato tubers, their correlations to chlorophyll levels, and the characteristics of photosynthetic fluorescence were studied.ResultsThe results indicated that spraying iron fertilizers increased the yield, quality and Fe content of the tubers, which might be due to the improvement of the plants’ photosynthetic pigment content, gas exchange parameters and chlorophyll fluorescence. In two consecutive years of cultivation, we found that potato tuber yield and Fe content increased in potatoes treated with five iron fertilizer sprays. Among them, tuber yield increased most significantly by T5 and T3 treatments compared to CK, while Fe content was significantly higher by the T5 treatment than by CK and other treatments. Tuber yield was increased by 33.28% and 18.85% in 2020 and 50.74% and 54.48% in 2021 by T5 and T3 treatments, respectively, compared to CK. Fe content was increased by 112.64% and 54.98% in 2020 and 2021 by T5 treatment, respectively, compared to CK.ConclusionsEDTA-Fe·Na and CA/Fe2(SO4)3 excelled over the other iron fertilizers. The findings of this study are instructive for developing cost-effective iron fertilizer management systems to maximize the impact of iron biofortification on human health.

BackgroundPotato (Solanum tuberosum L.) continuous cropping causes the decrease of tuber yield, deterioration of quality and soil degradation in the semi-arid area. These negative effects can generally be mitigated by legume rotation and mulching. However, little is known about how can mulching and legume rotation alleviate the above damage through altering soil environment.MethodsA field experiment was conducted to investigate changes in soil properties and microbial community in response to legume rotation and mulching under six planting patterns: potato continuous cropping without film mulching (PC), potato continuous cropping with film mulching (PCF), potato–broad bean rotation without film mulching (R1), potato–broad bean rotation with film mulching (R1F), potato–pea rotation without film mulching (R2) and potato–pea rotation with film mulching (R2F).ResultsCompared with the PC, the R1F and R2F had significantly enhanced the contents of alkaline nitrogen (AN), available phosphorus (AP), available potassium (AK), total carbon (TC) and total nitrogen (TN), but reduced soil pH and electrical conductivity (EC). The Shannon index of fungi in R1F and R2 was significantly higher than other treatments. The dominant bacterial and fungal phyla of each treatment was Proteobacteria and Ascomycota. R1, R1F, R2 and R2F enhanced the relative abundance of metabolic fungi and altered key differential microbial species. Soil EC, AN and AK were major factors influencing the soil bacterial and fungal communities.ConclusionOverall, the study demonstrated that potato-broad bean/pea rotation with mulching can be adopted as the preferred cropping systems to alleviate potato continuous cropping obstacles through enhancing soil fertility and regulating soil microbial communities in the semi-arid of Loess Plateau, China.

Daqu is a critical saccharifying and fermenting agent in the traditional solid-state production of strong-aroma Baijiu, with its physicochemical properties and microbial communities playing a vital role in both starter quality and final aroma. This study analyzed twelve Daqu samples from four key production regions in Sichuan Province—Luzhou (L), Suining (S), Yibin (Y), and Zigong (Z)—assessing physicochemical parameters such as moisture content, acidity, saccharification, liquefaction, and esterification activities. Microbial communities were characterized using Illumina high-throughput sequencing. Regional variations in physicochemical properties were observed, with Y showing the highest acidity, saccharification, and esterification activities. While no significant regional differences in alpha-diversity were found, β-diversity analysis (PCoA) revealed distinct microbial structures. Bacteria were predominantly represented by Bacillus , Lactobacillus , and Weissella , while Aspergillus , Saccharomycopsis , and Rhizopus dominated fungi. LEfSe analysis (LDA ≥ 4.0) identified region-specific microbial shifts. PICRUSt2 and FUNGuild predictions indicated significant potential for amino acid and carbohydrate metabolism, with saprotrophic fungi being dominant. Correlation analysis highlighted Thermoactinomyces , Weissella , Bacillus , and Rhizopus as key microbes influencing saccharification, starch degradation, and esterification. These findings provide insights into microbial and biochemical factors driving regional differences in Daqu, offering a foundation for standardized production methods and quality control. Graphical abstract

The effect of FP (a flat plot without mulch), FPM (a flat plot with film mulching), RM (on-ridge planting with full film mulching), and FM (on-furrow planting with full film mulching) on the tuber and its storage quality of continuous cropping potatoes was investigated. The results showed that with the increase of continuous cropping years, the potato yield was reduced year by year. The furrow-ridge mulching film can significantly increase potato yield and reduce small tubers. Among them, the yield of RM was the highest. From the perspective of tuber quality, RM had the highest dry matter content and starch content, while FP had the lowest. Meanwhile, the reducing sugar content of FP was always higher than that of other treatments. The amino acid content and vitamin C content of FPM, RM, and FM were higher than FP before and after storage. In addition, with the extension of storage time, the dry matter content, starch content, amino acid content, and vitamin C content of all treatments decreased, while the content of reducing sugar increased significantly. Thus, on-ridge planting with full film mulching (RM) can effectively improve potato yield and tuber quality before and after storage.