UV-B irradiation enhances the accumulation of beneficial glucosinolates induced by melatonin in Chinese kale sprout

Cruciferous sprout is a new form of vegetable product rich in bioactive compounds,especially glucosinolates.Previous studies have focused on increasing the accumulation of glucosinolates in cruciferous sprouts by applying different chemical regulators,with a particular focus on their contribution to nutritional quality and health benefits.Nevertheless,the effects of melatonin and UV-B irradiation on glucosinolate biosynthesis remain unclear.In this study,it was found that changes in melatonin concentrations significantly affected the contents of individual as well as total aliphatic and indolic glucosinolates.The 5μmol·L^(-1)melatonin was decided as the optimum concentration that could increase the content of beneficial glucosinolates including glucoraphanin and 4-methoxy glucobrassicin in Chinese kale sprouts.Notably,the enhancement of glucosinolate accumulation by melatonin treatment could be further amplified by UV-B irradiation.Furthermore,our results showed that R2R3-MYB transcription factor BoaMYB28 and BoaMYB51,which are central regulators of aliphatic and indolic glucosinolate biosynthesis respectively,were both involved in the regulation of glucosinolate biosynthesis by melatonin and UV-B irradiation.Additionally,the expression of glucosinolate biosynthetic genes,including BoaCYP79F1,BoaCYP83A1,BoaSUR1,BoaUGT74B1,BoaCYP79B2,BoaCYP79B3,and BoaCYP83B1 participated in the formation of core structures and BoaFMOGS-OX5,BoaAOP2,BoaCYP81F2,and BoaIGMT1 involved in the sidechain modification of aliphatic and indolic glucosinolate,was regulated by melatonin or UV-B irradiation.Taken together,these findings provide a potential strategy for improving the nutritional quality and resistance of Chinese kale sprouts.

Review on synergistic damage effect of irradiation and corrosion on reactor structural alloys

The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus.This paper provides a comprehensive review of the synergistic effects on the third-and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt reactors.The competitive mechanisms of multiple influencing factors,such as the irradiation dose,corrosion type,and environmental temperature,are summarized in this paper.Conceptual approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion,thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.

Neutron irradiation influence on high-power thyristor device under fusion environment

Because of their economy and applicability,high-power thyristor devices are widely used in the power supply systems for large fusion devices.When high-dose neutrons produced by deuterium–tritium(D–T)fusion reactions are irradiated on a thyristor device for a long time,the electrical characteristics of the device change,which may eventually cause irreversible damage.In this study,with the thyristor switch of the commutation circuit in the quench protection system(QPS)of a fusion device as the study object,the relationship between the internal physical structure and external electrical parameters of the irradiated thyristor is established.Subsequently,a series of targeted thyristor physical simulations and neutron irradiation experiments are conducted to verify the accuracy of the theoretical analysis.In addition,the effect of irradiated thyristor electrical characteristic changes on the entire QPS is studied by accurate simulation,providing valuable guidelines for the maintenance and renovation of the QPS.

In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the hardness.The results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being treated.It is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous clusters.The latter plays a key role in precipitation hardening.This result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

Microwave irradiation-induced alterations in physicochemical properties and methane adsorption capability of coals:An experimental study using carbon molecular sieve

In order to comprehend the applicability of microwave irradiation for recovering coalbed methane,it is necessary to evaluate the microwave irradiation-induced alterations in coals with varying levels of metamorphism.In this work,the carbon molecular sieve combined with KMnO_(4)oxidation was selected to fabricate carbon molecular sieve with diverse oxidation degrees,which can serve as model substances toward coals.Afterwards,the microwave irradiation dependences of pores,functional groups,and highpressure methane adsorption characteristics of model substances were studied.The results indicated that microwave irradiation causes rearrangement of oxygen-containing functional groups,which could block the micropores with a size of 0.40-0.60 nm in carbon molecular sieve;meanwhile,naphthalene and phenanthrene generated by macro-molecular structure pyrolysis due to microwave irradiation could block the micropores with a size of 0.70-0.90 nm.These alterations in micropore structure weaken the saturated methane adsorption capacity of oxidized carbon molecular sieve by 2.91%-23.28%,suggesting that microwave irradiation could promote methane desorption.Moreover,the increased mesopores found for oxidized carbon molecular sieve after microwave irradiation could benefit CH4 diffusion.In summary,the oxidized carbon molecular sieve can act as model substances toward coals with different ranks.Additionally,microwave irradiation is a promising technology to enhance coalbed methane recovery.

Two-dimensional particle-in-cell modeling of blow-off impulse by X-ray irradiation

Space objects such as spacecraft or missiles may be exposed to intense X-rays in outer space,leading to severe damage.The reinforcement of these objects to reduce the damage caused by X-ray irradiation is a significant concern.The blow-off impulse(BOI)is a crucial physical quantity for investigating material damage induced by X-ray irradiation.However,the accurate calculation of BOI is challenging,particularly for large deformations of materials with complex configurations.In this study,we develop a novel two-dimensional particle-in-cell code,Xablation2D,to calculate BOIs under far-field X-ray irradiation.This significantly reduces the dependence of the numerical simulation on the grid shape.The reliability of this code is verified by simulation results from open-source codes,and the calculated BOIs are consistent with the experimental and analytical results.

Effect of high-energy Ne ions irradiation on mechanical properties difference between Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5)metallic glass and crystalline W

In this paper,high-energy Ne ions were used to irradiate Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) metallic glass(MG)and crystalline W to investigate their difference in mechanical response after irradiation.The results showed that with the irradiation dose increased,the tensile micro-strain increased,nano-hardness increased from 7.11 GPa to 7.90 GPa and 8.62 GPa,Young’s modulus increased,and H3/E2 increased which indicating that the plastic deformability decreased in crystalline W.Under the same irradiation conditions,the Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG still maintained the amorphous structure and became more disordered despite the longer range and stronger displacement damage of Ne ions in Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG than in crystalline W.Unlike the irradiation hardening and embrittlement behavior of crystalline W,Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG showed the gradual decrease in hardness from 6.02 GPa to 5.89 GPa and 5.50 GPa,the decrease in modulus and the increase in plastic deformability with the increasing dose.Possibly,the irradiation softening and toughening phenomenon of Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG could provide new ideas for the design of nuclear materials.

Effect of three-volt moxibustion with helium-neon laser irradiation on quality of care in patients with lumbar radiculopathy spondylosis

BACKGROUND Lumbar radiculopathy spondylosis is a relatively common orthopedic disease with a high incidence rate.It most commonly occurs in the lumbar 4-5 and lumbar 5-sacral 1 vertebrae,which account for approximately 95%of cases.It mostly occurs in people aged 30-50 years old and greatly affects their quality of life.AIM To determine the effect of triple-voltage acupuncture combined with helium-neon laser irradiation on the quality of care and improvement of symptoms in patients with lumbar radiculopathy spondylolisthesis.METHODS In this study,we selected 120 patients with lumbar radiculopathy spondylosis who were treated at our hospital between June 2019 to June 2020.The patients were divided into control and observation groups according to the random number table method,with 60 patients in each group.Patients in the observation group were treated with three-volt moxibustion combined with helium-neon laser irradiation,and those in the control group were treated with lumbar traction.After 1 month of treatment,the lumbar pain scores,lumbar spine motor functions,clinical treatment effects,and nursing satisfaction of the two groups were compared.RESULTS The results showed that acupuncture combined with laser irradiation significantly improved the patients'clinical symptoms,i.e.,reduced their low back pain,significantly lower numerical rating scale pain scores in the observation group than in the control group,and better lumbar spine motility than in the control group,compared to lumbar traction.In addition,they were cared for.The treatment effectiveness rate of the observation group was 95.5%,which was significantly higher than that of the control group(81.67%).Satisfaction with care was higher than 90 points in both groups,but the difference was not statistically significant.CONCLUSION Our study provides a clinical rationale for the future treatment of patients with lumbar spine disease.However,further extensive research is needed for validation.

The impact of^(60)Co-γirradiation on the chemical constituents of Chuanxiong Rhizoma

Background:In order to clarify the inmpat ofγirradiation on the chemical composition of traditional Chinese medicine,this paper carefully choosed Chuanxiong Rhizoma to carry on a demonstration study.Methods:Through a meticulous assessment,a comprehensive comparison was made between the irradiated and unirradiated Chuanxiong Rhizoma samples.The property characteristics were investigated by colorimeter and electronic nose.The changes in chemical structures and contents was analyzed by fourier infrared spectroscopy,high performance liquid chromatography and fingerprinting.In a quest to uncover the presence of any new radiolysis products,cutting-edge techniques like ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry and gas chromatography-mass spectrometry were employed.Moreover,the difference of antioxidant activity were investigated.Results:The irradiation doses within 12 kGy had no significant effects on the content of the main chemical components,characteristics and in vitro antioxidant activity of Chuanxiong Rhizoma,while changes in some functional groups and degradation of some volatile oil components containing olefins need further study.Conclusion:This study indicates that^(60)Co-γirradiation is a stable method for sterilization of Chuanxiong Rhizoma.It’s also provide a reference for the establishment of irradiation standards for Chuanxiong Rhizoma and other aromatic medicinal plants.

Observation of therapeutic effect of lamp irradiation combined with purple gromwell oil gauze on alleviating intestinal colic in patients

BACKGROUND Intestinal colic is a common complication in patients who have undergone radical surgery for colorectal cancer.Traditional Chinese medicine has advantages,including safety and stability,for the treatment of intestinal colic.Lamp irra-diation for abdominal ironing has been applied in the treatment of many gas-trointestinal diseases.Purple gromwell oil has the effects of clearing heat,cooling blood,reducing swelling,and relieving pain.RESULTS The general effective rate in the observation group was 95.00%,which was significantly higher than that in the control group(86.67%,P<0.05).Before treatment,there was no significant difference in the duration of symptoms between the groups(P>0.05).After 1,2,3,and 4 d of treatment,the duration of symptoms in both groups were decreased,and the duration in the observation group was significantly lower than that in the control group(96.54±9.57 vs 110.45±11.23,87.26±12.07 vs 104.44±11.68,80.45±16.21 vs 99.44±14.95,73.18±15.58 vs 92.17±14.20;P<0.05).After 1,3,5,and 7 d of treatment,the NRS scores in both groups were decreased,and the NRS scores in the observation group were significantly lower than those in the control group(3.56±0.41 vs 4.04±0.58,3.07±0.67 vs 3.74±1.02,2.52±0.76 vs 3.43±0.85,2.03±0.58 vs 3.03±0.82;P<0.05).There was no significant difference in the rate of adverse reaction occurrence between the groups(P>0.05).CONCLUSION The use of lamp irradiation combined with purple gromwell oil gauze in patients with intestinal colic after radical surgery for colorectal cancer can reduce symptom duration,alleviate intestinal colic,and improve treatment efficacy,and this approach is safe.It is worth promoting the use of this treatment in clinical practice.

Protective and Regenerative Efficacy of a Plant Oil-Based Day and Night Cream: Investigated by a Novel Approach to Reveal the Impact of Blue Light Irradiation on Epidermal Barrier Integrity and Lipid Matrix

In recent years, the harmful effects of blue light (400 - 500 nm) as a component of visible light (400 - 700 nm) have increasingly gained attention of science, industry, and consumers. To date, only a few in vivo test methods for measuring the effects of blue light on the skin have been described. A direct measurement method that can detect the immediate effects of blue light on the epidermal permeability barrier (EPB) is still lacking. In this study, we present a new methodological approach that can be used to investigate both the protective and regenerative effects of cosmetic products on the EPB after blue light irradiation. In a study with 14 female volunteers, it was investigated whether the regular application of an O/W emulsion (day cream) can strengthen and protect the epidermal barrier against damaging blue light radiation of 60 J/cm2 (protective study design) and also whether a disruption of the epidermal barrier caused by blue light radiation is restored faster and better by the regular application of another O/W emulsion (night cream) than in product-untreated skin (regenerative study design). The two O/W emulsions are different in plant oil, active ingredient composition and texture. The seven-day treatment with the day cream initially led to a significant increase in the normalized lipid lamellae length in the intercellular space, whereas the irradiation with blue light after 24 hours led to a significant decrease in the lipid lamellae length in the untreated test area, but not in the area previously treated with the product. Regarding the regenerative study design, a two-day treatment with the night cream was able to restore a blue-light-induced decrease in lipid lamellae length in the intercellular space. In summary, with the study designs presented here, the protective and regenerative effect of two cosmetic products could be demonstrated for the first time on the integrity of the EPB after blue light irradiation and the data showed that the Lipbarvis® method is suitable for investigating the damaging effects of blue light on the EPB in vivo.

UV-B不同剂量辐照下生菜生长和代谢组学分析

以奶油生菜为研究材料,在植物工厂人工光源中设置3种紫外线B(UV-B)剂量[0、8.64、17.28 kJ/(m^(2)·d)]处理,利用广靶代谢组学技术,分析不同剂量UV-B辐照下生菜叶片中的差异代谢物质,研究UV-B辐照对生菜生物量、光合参数和次生代谢物的影响。结果表明,与0剂量相比,低剂量UV-B处理对生菜生物量、光合参数均未产生显著影响,代谢组检测到30种差异代谢产物,主要为生物碱、酚类、萜类等物质,其中9种上调表达,21种下调表达;高剂量UV-B处理显著降低了生菜地上部干重、地下部干重、气孔导度和蒸腾速率,但地上部鲜重、净光合速率均未呈现显著差异,共检测到35个差异表达代谢物,其中21种上调表达,14种下调表达,上调表达的代谢物主要为黄酮类、单萜等,生菜叶片槲皮素含量在低剂量、高剂量UV-B处理下均显著增加。研究结果可为利用UV-B辐照提高设施生菜营养品质提供理论依据和参考。

UV-B照射时长对酿酒葡萄果实品质及类黄酮代谢产物的影响

为探明UV-B照射时长对赤霞珠酿酒葡萄果实品质及类黄酮物质的影响,试验设立UV-B每天分别照射2、4、6、8 h共4个梯度,以不进行UV-B照射为对照(CK),对不同UV-B照射时长葡萄果实品质及类黄酮物质进行检测分析。结果表明,短时间的UV-B照射会增加果实中可溶性糖含量,UV-B不同照射时长处理的总酚、单宁、总类黄酮、黄烷-3-醇和总花色苷含量均增加;UV-B不同照射时长对酿酒葡萄果皮中的类黄酮代谢产物影响显著,筛选出差异代谢物13个,其中5种物质显著上调、8种物质显著下调;在类黄酮和次生代谢产物合成通路上分别富集了7个差异代谢物,占代谢物总数的77.78%。利用主成分对果实品质和果皮类黄酮产物测定值进行综合评价,得分从高到低依次为UV-B照射2 h>UV-B照射8 h>UV-B照射4 h>UV-B照射6 h>CK。UV-B照射酿酒葡萄赤霞珠2 h时,果实品质和类黄酮代谢产物表现最佳。

Simple synthesis of silver nanocluster composites AgNCs@PE-g-PAA by irradiation method and fluorescence detection of Cr^(3+)

Silver nanoclusters(AgNCs)are a new type of nanomaterials with similar properties to molecules and unique applications.The applications of AgNCs can be significantly expanded by combining them with different matrix materials to obtain AgNC composites.Using irradiation techniques,we developed a simple two-step method for preparing silver nanocluster composites.First,polyacrylic acid(PAA)chains were grafted onto the surface of a PE film as templates(PE-g-PAA).Subsequently,silver ions were reduced in situ on the surface of the template material to obtain the AgNC composites(AgNCs@PE-g-PAA).The degree of AgNC loading on the composite film was easily controlled by adjusting the reaction conditions.The loaded AgNCs were anchored to the carboxyl groups of the PAA and wrapped in the graft chain.The particle size of the AgNCs was only 4.38±0.85 nm,with a very uniform particle size distribution.The AgNCs@PE-g-PAA exhibited fluorescence characteristics derived from the AgNCs.The fluorescence of the AgNCs@PE-g-PAA was easily quenched by Cr^(3+)ions.The composite can be used as a fluorescence test paper to realize visual detection of Cr^(3+).

Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupia filicina(Rhodophyta)

Macroalgae in a littoral zone are inevitably exposed to UV-B irradiance. We analyzed the effects of UV-B on isoenzyme patterns and activities of superoxide dismutase （SOD）, peroxidase （POX）, catalase （CAT）, and ascorbate peroxidase （APX） of red algae Grateloupia filicina （Lamour.） C. Agardh. The activities of SOD, CAT, and APX changed in response to UV-B in a time- and dose-dependent manner. POX activity increased significantly under all three UV-B treatments. The enzymatic assay showed three distinct bands of SODI （Mn-SOD）, SODII （Fe-SOD）, and SODIII （CuZn-SOD） under a low （Luv） and medium （Muv） dose of UV-B irradiation, while SODI and SODIII activities decreased significantly when exposed to a high dose of UV-B irradiation （Huv）. The activity of POX isoenzymes increased significantly after exposure to UV-B, which is consistent with the total activity. In addition, a clear decrease in activity of CATIV was detected in response to all the three doses of UV treatments. Some bands ofAPX isoenzyme were also clearly influenced by UV-B irradiation. Correspondingly, the daily growth rate declined under all the three exposure doses, and was especially significant under Muv and Huv treatments. These data suggest that, although the protection mechanisms of antioxidant defense system are partly inducible by UV-B to prevent the damage, G.filicina has incomplete tolerance to higher UV-B irradiation stress.

Bi-LSTM-Based Deep Stacked Sequence-to-Sequence Autoencoder for Forecasting Solar Irradiation and Wind Speed

Wind and solar energy are two popular forms of renewable energy used in microgrids and facilitating the transition towards net-zero carbon emissions by 2050.However,they are exceedingly unpredictable since they rely highly on weather and atmospheric conditions.In microgrids,smart energy management systems,such as integrated demand response programs,are permanently established on a step-ahead basis,which means that accu-rate forecasting of wind speed and solar irradiance intervals is becoming increasingly crucial to the optimal operation and planning of microgrids.With this in mind,a novel“bidirectional long short-term memory network”(Bi-LSTM)-based,deep stacked,sequence-to-sequence autoencoder(S2SAE)forecasting model for predicting short-term solar irradiation and wind speed was developed and evaluated in MATLAB.To create a deep stacked S2SAE prediction model,a deep Bi-LSTM-based encoder and decoder are stacked on top of one another to reduce the dimension of the input sequence,extract its features,and then reconstruct it to produce the forecasts.Hyperparameters of the proposed deep stacked S2SAE forecasting model were optimized using the Bayesian optimization algorithm.Moreover,the forecasting performance of the proposed Bi-LSTM-based deep stacked S2SAE model was compared to three other deep,and shallow stacked S2SAEs,i.e.,the LSTM-based deep stacked S2SAE model,gated recurrent unit-based deep stacked S2SAE model,and Bi-LSTM-based shallow stacked S2SAE model.All these models were also optimized and modeled in MATLAB.The results simulated based on actual data confirmed that the proposed model outperformed the alternatives by achieving an accuracy of up to 99.7%,which evidenced the high reliability of the proposed forecasting.

外源褪黑素对UV-B胁迫下水稻幼苗生理特性及抗氧化系统的影响

褪黑素作为一种广谱的抗氧化剂,已被证明在植物的多种逆境胁迫中发挥重要的保护作用。为探讨外源褪黑素(MT)对UV-B胁迫下水稻幼苗生理特性及抗氧化系统的影响,以日本晴为试验材料,待水稻幼苗生长至22 d时,于22:00时对其叶面喷施100μmol/L MT,置于黑暗中进行暗处理,预处理2 d后,每天09:00—20:00进行UV-B+100μmol/L MT处理,探究UV-B胁迫(80 W)下外源喷施100μmol/L MT对水稻幼苗生长、叶绿素含量、活性氧水平以及MDA含量、抗氧化酶活性的影响。结果表明,UV-B+100μmol/L MT处理3 d后,水稻幼苗的株高、根长、鲜重和干重与UV-B处理相比分别提高25.8%、12.3%、21.6%和20.6%;叶绿素a、叶绿素b、类胡萝卜素含量与UV-B处理相比分别提高52.6%、39.6%、44.4%;UV-B处理后水稻幼苗中的丙二醛(MDA)、过氧化氢(H2O2)、超氧阴离子自由基(O_(2)^(-)·)、游离脯氨酸含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)活性均显著高于对照,可溶性糖、可溶性蛋白含量显著低于对照,用UV-B+100μmol/L MT处理后,水稻幼苗中的MDA、H_(2)O_(2)、O_(2)^(-)·含量以及游离脯氨酸含量均较UV-B处理显著降低,SOD、POD活性以及可溶性糖、可溶性蛋白含量均较UV-B处理显著提高。相关性分析结果表明,MDA含量与游离脯氨酸、H2O2含量之间呈显著正相关,叶绿素a(Chl a)、类胡萝卜素(Car)含量与可溶性糖、可溶性蛋白含量以及CAT活性之间互呈显著正相关。由此可见,外源喷施MT可以使水稻在紫外胁迫下保持良好的长势,降低膜脂过氧化损伤程度,提高抗氧化酶活性,有效缓解UV-B胁迫对水稻幼苗造成的氧化损伤。

UV-B增强后秸秆还田分解对土壤氮转化微生物及酶活性的影响

为明确UV-B辐射增强对水稻秸秆化学成分的影响,阐释UV-B辐射增强后秸秆还田分解特征及其对稻田土壤氮素转化的间接效应,本研究在元阳梯田(海拔1600 m)开展大田试验,以当地水稻品种白脚老粳为研究对象,研究UV-B辐射增强(5.00kJ·m^(-2))对水稻秸秆化学成分及其还田后秸秆降解、土壤氮素转化的影响。结果表明:UV-B辐射增强显著降低水稻秸秆纤维素含量,增加木质素含量,提高秸秆木质素/氮;并导致秸秆纤维素、木质素、总氮的降解速率总体降低,最大降幅分别达38.7%、18.1%、25.8%。与自然光照秸秆相比,UV-B辐射后的秸秆还田显著降低土壤固氮细菌、氨化细菌、硝化细菌和反硝化细菌数量,增加土壤蛋白酶、氨单加氧酶、硝酸还原酶活性,提高土壤硝化和反硝化速率。相关性分析表明,秸秆木质素/氮与秸秆降解速率呈极显著负相关;秸秆纤维素、木质素、总氮降解速率与硝酸还原酶活性呈显著正相关,后者又与N_(2)O排放通量呈显著正相关;硝化细菌数量与NO_(3)^(-)-N含量呈负相关。研究表明,UV-B辐射增强通过提高秸秆木质素/氮,抑制秸秆纤维素、木质素、总氮降解,减少土壤氨化细菌数量,增加氨单加氧酶和硝酸还原酶活性,从而促进土壤NH_(4)^(+)-N向NO_(3)^(-)-N转化,导致N2O排放通量增加。

Effect of UV-B irradiation on interspecific competition between Ulva pertusa and Grateloupia filicina

We report the effect of UVoB irradiation （9.6 kJ m-2 day^-） on interspecific competition between two species of macroalgae, Ulva pertusa （U） and Grateloupiafilicina （G）, in co-culture. Growth of U. pertusa and G. filicina was inhibited by UV-B irradiation in mono-culture and specific growth rate （μ） declined as a result. Interspecific competition between U. pertusa and G filicina was closely related to the initial weights when co-cultured. When initial ratios of U. pertusa （U） to G filicina （G） were U：G=I.2：I and 1：1, U. pertusa was the dominant algae. When the initial U：G ratio was 1：1.2, G. filicina was competitively dominant in the earlier stage, but U. pertusa grew faster, superseding G. filicina in the later stage. At initial ration U：G = 1：1.4, G. filicina was predominant. Under UV-B irradiation, the competitive ability of G filicina was weakened and the interspecific competitive balance favored U. pertusa, which suggests that G. filicina was more sensitive to UV-B irradiation. We also probed the potential allelopathic effects between the two species, which led to mutual growth inhibition.

模拟增强UV-B辐射下台农一号芒果抗氧化响应机理

【目的】研究增强UV-B辐射下台农一号芒果果肉抗氧化还原性成分的响应机理,为全球气候变化下芒果生产提供理论参考。【方法】以自然光照射为对照,设人工模拟增强UV-B辐射,强度为96 k J/(m^(2)·d)处理。2021年花后30 d(12月18日)至花后90 d(2022年2月17日)、2022年花后40 d(12月1日)至花后90 d(2023年1月21日),每隔10 d取芒果果肉样本1次,分别取样共7和6次。在果肉中测定各采样时期的总黄酮、总酚、超氧阴离子、过氧化氢(H_(2)O_(2))和丙二醛(MDA)含量,以及苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)酶活性、相对电导率(REC)的动态变化。【结果】经增强UV-B辐射处理后,第1和2年活性氧(ROS)中超氧阴离子含量随时间的增加均呈逐渐升高趋势,超氧阴离子在第1年花后90 d、翌年花后70~90 d,辐射处理显著高于对照(P<0.05,下同);辐射处理的H_(2)O_(2)变化趋势则为第1年先下降后上升,仅花后90 d辐射处理显著高于对照,翌年总体上下降,花后70~90 d辐射处理均显著高于对照。芒果果肉中总酚和总黄酮含量2年动态变化均整体呈下降趋势,总酚在第1年花后50 d、翌年花后50和60 d,辐射处理显著高于对照;总黄酮在第1年花后40和50 d、翌年花后50和60 d,辐射处理显著高于对照。MDA含量和REC的2年变化趋势均为下降后上升,其中MDA含量在第1年花后40 d、翌年花后50 d,对照显著高于辐射处理,而2年在花后90 d MDA含量和REC均表现为辐射处理显著高于对照。芒果果肉辐射处理的PAL活性在第1年呈下降—上升—下降的变化趋势,花后40 d辐射处理显著高于对照,花后90 d时无显著差异;翌年呈上升—下降—上升的变化趋势,辐射处理50~70 d均表现为显著差异。PPO活性2年测定中的动态变化均呈先降后升的变化趋势,第1年在辐射处理40、60、70和80 d PPO活性显著高于对照,翌年花后60和90 d辐射处理显著高于对照。【结论】增强UV-B辐射处理下的芒果主要通过调节PAL活性来控制合成以黄酮为主的酚类化合物,并作为应对UV-B辐射的高效抗氧化剂。