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。

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。

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。

Lycium barbarum glycopeptide(wolfberry extract)slows N-methyl-N-nitrosourea-induced degradation of photoreceptors

Photoreceptor cell degeneration leads to blindness, for which there is currently no effective treatment. Our previous studies have shown that Lycium barbarum(L. barbarum) polysaccharide(LBP) protects degenerated photoreceptors in rd1, a transgenic mouse model of retinitis pigmentosa. L. barbarum glycopeptide(Lb GP) is an immunoreactive glycoprotein extracted from LBP. In this study, we investigated the potential protective effect of Lb GP on a chemically induced photoreceptor-degenerative mouse model. Wild-type mice received the following: oral administration of Lb GP as a protective pre-treatment on days 1–7;intraperitoneal administration of 40 mg/kg N-methylN-nitrosourea to induce photoreceptor injury on day 7;and continuation of orally administered Lb GP on days 8–14. Treatment with Lb GP increased photoreceptor survival and improved the structure of photoreceptors, retinal photoresponse, and visual behaviors of mice with photoreceptor degeneration. Lb GP was also found to partially inhibit the activation of microglia in N-methyl-N-nitrosourea-injured retinas and significantly decreased the expression of two pro-inflammatory cytokines. In conclusion, Lb GP effectively slowed the rate of photoreceptor degeneration in N-methyl-N-nitrosourea-injured mice, possibly through an anti-inflammatory mechanism, and has potential as a candidate drug for the clinical treatment of photoreceptor degeneration.

彩色马铃薯响应UV-B辐射的转录组分析

[目的]探究彩色马铃薯对UV-B辐射具有较强耐受性的机理,通过转录组分析马铃薯对UV-B辐射响应的分子机制,为筛选马铃薯耐UV-B辐射相关基因提供理论依据。[方法]以彩色马铃薯‘花心洋芋’为试验材料,对全生育期进行UV-B辐射处理,选取成熟期的块茎,采用Illumina HiseQ2500平台进行测序分析。[结果]共得到232 285 320个有效测序读长数,且与参考基因组比对率超过78.5%,GC含量均超过42.1%。通过分析筛选到843个差异表达基因(DEGs),包括544个上调基因和299个下调基因。GO功能分析表明,‘花心洋芋’的DEGs主要富集在代谢过程、细胞组分和催化活性。KEGG富集分析发现,‘花心洋芋’主要通过代谢途径中的碳水化合物代谢通路来响应UV-B辐射,转录因子主要是ARR-B、AP2-EREBP、MADS、bHLH和NAC等,与响应光信号和环境胁迫相关。[结论]‘花心洋芋’响应UV-B辐射的主要通路为代谢途径中的碳水化合物代谢通路,转录因子ARR-B、AP2-EREBP、MADS、bHLH和NAC均起到一定的调控作用。

外源褪黑素提高马铃薯幼苗UV-B辐射耐性的转录组学分析

随着人类活动对大气层臭氧的破坏,导致到达地面的UV-B辐射增强,而严重的UV-B辐射会直接导致马铃薯产量、品质大幅度降低。马铃薯作为云南省重要的粮食作物,由于云南省具有特殊的地理位置,使马铃薯面临的UV-B辐射较为严峻。为探究褪黑素对增强马铃薯耐UV-B辐射的分子机制,以马铃薯品种合作88为试验材料,对外源褪黑素处理UV-B辐射下的马铃薯叶片进行转录组测序,并进行基因本体(gene ontology, GO)功能聚类分析及京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes, KEGG)功能聚类分析。结果表明,褪黑素可以促进马铃薯植株中缬氨酸、亮氨酸和异亮氨酸生物合成及精氨酸、脯氨酸代谢,提高内质网上蛋白质的加工水平,促进抗氧化物质编码基因的表达,激活UVR8等UV-B辐射的响应基因,从而缓解UV-B辐射对马铃薯植株的危害。综上所述,适量浓度的褪黑素对提高马铃薯耐UV-B辐射有积极作用,研究结果可为马铃薯抗UV-B辐射机制解析提供新的证据,并为其抗UV-B辐射研究提供一定的分子基础。

Protective effects of CY-09 and astaxanthin on NaIO_(3)-induced photoreceptor inflammation via the NLRP3/autophagy pathway

AIM:To study the effect of the NLRP3/autophagy pathway on the photoreceptor inflammatory response and the protective mechanism of CY-09 and astaxanthin(AST).METHODS:ICR mice were intraperitoneally injected NaIO_(3),CY-09,AST successively and divided into 5 groups,including the control,NaIO_(3),NaIO_(3)+CY-09,NaIO_(3)+AST,and NaIO_(3)+CY-09+AST groups.Spectral domain optical coherence tomography and flash electroretinogram were examined and the retina tissues were harvested for immunohistochemistry,enzyme linked immunosorbent assay(ELISA),and Western blotting.Retinal pigment epithelium cell line(ARPE-19 cells)and mouse photoreceptor cells line(661W cells)were also treated with NaIO_(3),CY-09,and AST successively.Cell proliferation was assessed by cell counting kit-8(CCK-8)assay.Apoptosis was analyzed by flow cytometry.Changes in autophagosome morphology were observed by transmission electron microscopy.Quantitative polymerase chain reaction(qPCR)was used to detect NLRP3 and caspase-1.NLRP3,caspase-1,cleaved caspase-1,p62,Beclin-1,and LC3 protein levels were measured by Western blotting.IL-1βand IL-18 were measured by ELISA.RESULTS:Compared with the control group,the activity of NaIO_(3)-treated 661W cells decreased within 24 and 48h,apoptosis increased,NLRP3,caspase-1,IL-1βand IL-18 levels increased,and autophagy-related protein levels increased(P<0.05).Compared with NaIO_(3) group,CY-09 and AST inhibited apoptosis(P<0.05),reduced NLRP3,caspase-1,IL-1βand IL-18 expression(P<0.05),and inhibited autophagy.Compared with the other groups,CY-09 combined with AST significantly decreased NLRP3 expression and inhibited the expression of the autophagy-related proteins p62,Beclin-1,and LC3 in vitro and in vivo(P<0.05).CONCLUSION:CY-09 and AST inhibit NaIO_(3)-induced inflammatory damage through the NLRP3/autophagy pathway in vitro and in vivo.CY-09 and AST may protect retina from inflammatory injury.

青稞BBX基因家族鉴定及其对UV-B的响应

B-box(BBX)蛋白是植物中一类重要的转录因子,在控制植物生长发育、响应环境胁迫中起着重要作用。本研究从青稞(Hordeum vulgare L.var.nudum Hook.f.)全基因组中鉴定出18个青稞BBX基因家族成员,分析了它们的理化性质、基因结构、进化关系及UV-B照射幼苗后的表达特性等。结果表明:青稞BBX基因的编码序列(CDS)长度为636~2 223 bp;分子质量为22.07~54.29 kDa。系统发育分析将18个HvnBBX分为4个亚类。共线性分析表明青稞种内共产生4对片段复制形成的基因对,种间与玉米进化关系更近;HvnBBX启动子区域包含与逆境胁迫、激素、生长发育等相关顺式作用元件。转录组测序结果显示UV-B照射后青稞叶片中有5个BBX基因(HvnBBX2/4/5/6/17)的表达量显著下调,qRT-PCR验证结果与转录组测序一致。上述结果为深入研究HvnBBX基因的抗紫外功能提供参考。

Optimal transcorneal electrical stimulation parameters for preserving photoreceptors in a mouse model of retinitis pigmentosa

Retinitis pigmentosa is a hereditary retinal disease that affects rod and cone photoreceptors,leading to progressive photoreceptor loss.Previous research supports the beneficial effect of electrical stimulation on photoreceptor survival.This study aims to identify the most effective electrical stimulation parameters and functional advantages of transcorneal electrical stimulation(tcES)in mice affected by inherited retinal degeneration.Additionally,the study seeked to analyze the electric field that reaches the retina in both eyes in mice and post-mortem humans.In this study,we recorded waveforms and voltages directed to the retina during transcorneal electrical stimulation in C57BL/6J mice using an intraocular needle probe with rectangular,sine,and ramp waveforms.To investigate the functional effects of electrical stimulation on photoreceptors,we used human retinal explant cultures and rhodopsin knockout(Rho^(-/-))mice,demonstrating progressive photoreceptor degeneration with age.Human retinal explants isolated from the donors’eyes were then subjected to electrical stimulation and cultured for 48 hours to simulate the neurodegenerative environment in vitro.Photoreceptor density was evaluated by rhodopsin immunolabeling.In vivo Rho^(-/-)mice were subjected to two 5-day series of daily transcorneal electrical stimulation using rectangular and ramp waveforms.Retinal function and visual perception of mice were evaluated by electroretinography and optomotor response(OMR),respectively.Immunolabeling was used to assess the morphological and biochemical changes of the photoreceptor and bipolar cells in mouse retinas.Oscilloscope recordings indicated effective delivery of rectangular,sine,and ramp waveforms to the retina by transcorneal electrical stimulation,of which the ramp waveform required the lowest voltage.Evaluation of the total conductive resistance of the post-mortem human compared to the mouse eyes indicated higher cornea-to-retina resistance in human eyes.The temperature recordings during and after electrical stimulation indicated no significant temperature change in vivo and only a subtle temperature increase in vitro(~0.5-1.5°C).Electrical stimulation increased photoreceptor survival in human retinal explant cultures,particularly at the ramp waveform.Transcorneal electrical stimulation(rectangular+ramp)waveforms significantly improved the survival and function of S and M-cones and enhanced visual acuity based on the optomotor response results.Histology and immunolabeling demonstrated increased photoreceptor survival,improved outer nuclear layer thickness,and increased bipolar cell sprouting in Rho^(-/-)mice.These results indicate that transcorneal electrical stimulation effectively delivers the electrical field to the retina,improves photoreceptor survival in both human and mouse retinas,and increases visual function in Rho^(-/-)mice.Combined rectangular and ramp waveform stimulation can promote photoreceptor survival in a minimally invasive fashion.

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.

中波紫外线(UV-B)辐照处理对糯玉米种子萌发影响的转录组分析

为了解中波紫外线(UV-B)对糯玉米种子活力影响的分子机理,设置0 min(对照)、30 min、1 h、2 h、4 h和8 h共6个不同时长的UV-B辐照对糯玉米自交系N51种子进行处理,同时进行相关活力指标和转录组学分析。结果表明,糯玉米自交系N51各处理与对照及各处理间差异均不显著。在0 min、30 min、1 h、2 h、4 h、8 h范围内,发芽势、发芽指数和活力指数均呈先上升后下降的趋势,且在1 h处理下达到最高,综合各个活力指标表明,UV-B辐照处理1 h促进玉米种子萌发效果最显著。依据0 min、1 h、2 h等3个时长处理下,糯玉米种子活力指标呈先升后降的趋势,转录组测序分析共筛选出先上调再下调的差异表达基因5个,先下调后上调的差异表达基因869个。GO注释分类表明,UV-B处理主要通过影响类囊体、光合系统光合作用、光合膜、光合作用-天线蛋白、代谢途径、氮代谢途径等影响糯玉米自交系N51种子萌发;KEGG通路富集包括苯丙素类生物合成、类黄酮生物合成、淀粉和蔗糖代谢等途径。

UV-B辐射对滇黄精幼苗生长、抗性生理及代谢物的影响

为探究滇黄精幼苗对UV-B辐射的生理响应机制,以两年生药用植物滇黄精为材料,在540 mw/cm^(2)的UV-B辐射强度下,以5 d为一个周期,分别测定处理了0~25 d后的滇黄精幼苗的生物量、抗氧化酶活性、MDA、类黄酮的含量.结果表明:在UV-B辐射下,滇黄精幼苗的株高与叶绿素含量呈下降趋势,并随着辐射时间延长,影响效果更明显,UV-B辐射对POD、SOD活性的影响呈升高趋势,在UV-B辐射中期,相较于CK显著升高.对MDA含量的影响呈现先升高后降低的趋势.滇黄精叶片中类胡萝卜素含量及叶片和块茎中类黄酮含量也随着辐射时间的延长而增加.因此,UV-B辐射处理可抑制滇黄精幼苗的生长,使其抗氧化酶活性以及类黄酮含量显著增加,从而增强滇黄精对UV-B辐射的抗性,对植株起到保护作用.

增强UV-B胁迫对小麦幼苗CaM含量的影响

[目的]对增强UV-B胁迫下小麦幼苗中钙调素(CaM)含量进行研究,进而研究增强UV-B胁迫下小麦幼苗体内Ca^(2+)-CaM通路的情况。[方法]采用二次盐析、Sephadex G-50凝胶过滤层析等方法,从小麦幼苗中分离纯化的CaM,并采用PDE法测定CaM含量。[结果]增强UV-B胁迫导致小麦幼苗CaM含量增加了23%,这可能为增强UV-B胁迫导致钙离子增多,进而调控CaM所致。[结论]结果为小麦抗辐射机制的研究奠定了一定的基础。

过表达AtAUR1对UV-B胁迫下根尖细胞周期调控的影响

随着南北两极臭氧层空洞的持续增大,UV-B辐射对整个地球的生态系统造成的危机不断增强.植物受其特殊生活方式的影响,更容易遭受增强UV-B辐射的影响.UV-B辐射作为一种非生物压力信号会造成植物细胞DNA的损伤从而显著抑制植物生长,严重时甚至会导致植物的死亡.Aurora激酶作为调控有丝分裂的重要蛋白,在有丝分裂过程中参与了染色体的定位、分离以及胞质分裂等过程,实验室之前的研究结果表明过表达AUR1可以缓解UV-B辐射导致的损伤.研究以模式植物拟南芥为材料,通过有性杂交的方法获得含CYCB1;1-GUS标签的拟南芥AUR1过表达株系.通过GUS染色和RT-qPCR的方法对获得的转基因株系在UV-B处理后CYCB1;1的组织表达模式进行了分析,实验结果证明了过表达AUR1可以上调植物根尖细胞中CYCB1;1的基因表达,UV-B辐射处理后的染色结果进一步证明了AUR1参与了UV-B辐射后根尖有丝分裂周期的调控,为揭示过表达AUR1对根尖有丝分裂周期调控的影响提供了一定的理论基础.

UV-B补光灯对茄子幼苗生长、抗性生理及抗病性的影响

为探究寡照天气下UV-B补光灯对茄子幼苗生长、抗性生理及抗病性的作用,以长杂218茄子为试材,设置自然光(CK)、LED补光(T1)和UV-B补光(T2)3种不同补光处理,在茄子4叶1心时进行UV-B补光对茄子幼苗接种3种不同病原菌抗病性的研究。结果表明:T2处理综合表现最佳,在补光第25 d,株高较CK显著降低7.9%,其株高、茎粗、叶面积和叶片数在补光处理时间内均显著高于CK;在补光第25 d,T2处理叶片中CAT、POD、SOD和APX活性较CK分别增加127.17%、35.55%、50.25%和29.28%,且差异显著,有利于茄子幼苗壮苗的形成和抗氧化系统活性的提高;T2处理幼苗叶片中MDA含量显著降低,H2O2含量上升,总酚和类黄酮含量保持在较高水平,有利于幼苗抗菌能力增加;T2处理对茄子幼苗早疫病、灰霉病和炭疽病的发生起到显著抑制作用。

光受体UVR8对UV-B响应机制研究进展

来自太阳光谱中的UV-B辐射被认为是一种重要的环境信号,可以被植物感受并诱导植物调整自身生长和发育状态以适应环境。人们对植物中光敏色素、隐花色素和蓝光受体向光素的研究已非常深入,但对植物响应UV-B的机制仅在最近才取得一些突破性进展。这些研究发现,植物中存在着UV-B受体UVR8(UV Resistance Locus 8)。目前认为,UVR8二聚体感应UV-B后瞬间解聚为单体,并与E3泛素连接酶COP1(constitutively photomorphogenic 1)相互作用,从而激活UV-B响应基因的表达。该文从UVR8的发现、UVR8的结构和感受UV-B机制、UVR8二聚体重新形成以及UV-B信号传导与可见光信号传导途径间的差异等方面综述了关于UV-B受体UVR8的最新研究成果。

水稻对UV-B辐射响应的敏感性差异

综述了UV-B辐射对水稻(Oryza sativa L.)的影响和水稻对UV-B辐射的抗性机制。UV-B辐射对水稻生长、叶片形态、生物量、产量、光合系统、病害等产生一定的影响。水稻对UV-B辐射的敏感性因子主要有CPD光解酶、UV-B吸收物质、抗氧化酶等。UV-B辐射使水稻叶片中产生了ROS,导致Rubisco酶降解,光合色素含量变化,抑制了光合作用,最终影响水稻籽粒形成和产量。水稻对UV-B辐射响应存在着品种差异,CPD光解酶编码基因的自然突变会引起水稻UV-B敏感性的差异,CPD光解酶活性是水稻对UV-B敏感性的关键因素。通过建立响应指数公式,对水稻UV-B响应敏感性的品种差异进行评估,存在品种差异的原因主要是基因、生长、生理、生育期和环境背景的差异。最后对UV-B辐射对水稻的影响、水稻对UV-B响应的差异及机理有待深入研究的方向进行了展望。

褪黑素对绿豆在增强UV-B辐射下的防护作用

研究了外源褪黑素对于绿豆幼苗在增强UV-B辐射下叶片内丙二醛含量、过氧化物酶、超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶酶活的影响.实验结果表明,增强UV-B辐射对绿豆产生了氧化胁迫,使其叶片内的丙二醛含量升高,引起抗氧化酶包括过氧化物酶、抗坏血酸过氧化物酶、超氧化物歧化酶和过氧化氢酶酶活提高.而外源褪黑素和UV-B辐射复合处理可以显著地降低绿豆叶片内的丙二醛含量、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶酶活.褪黑素单独处理绿豆使各项指标与对照无显著差异.表明在植物体内,褪黑素是一种保护性抗氧化剂,加入一定浓度的外源褪黑素可以减缓UV-B辐射引起绿豆的氧化胁迫.