Vc和VE对不同辐射敏感性作物膜脂过氧化的防护效应

本研究了Ｖｃ和ＶＥ与作物辐射敏感性的叛乱及其对细胞膜过氧化水平的影响。结果表明，随辐照剂量的增大，辐射敏感性不同的大豆、油菜，其５ｄ龄幼苗下胚轴中Ｖｃ和ＶＥ的含量逐渐下降，膜脂氧化产物ＭＤＡ的含量逐渐上升，ＳＯＤ酶的活性先增后减。追施Ｖｃ和ＶＥ后不同程度地提高了两种不同辐射敏感性的作物ＳＯＤ酶的活性，降低了ＭＤＡ的含量。因此，Ｖｃ和ＶＥ具有降低不同辐射敏感性的作物的辐射敏感性及膜脂过氧化水平的作     

红细胞膜辐射损伤的研究进展

生物膜具有重要的生物学功能,其损伤将会严重干扰细胞代谢的方向性、有序性和协调性,最终导致细胞的死亡。本文就红细胞的膜组分、膜功能以及抗氧化体系等方面介绍了辐射对红细胞膜的损伤效应。     

~(60)Coγ辐射对金鱼胚胎发育的影响

本文以金鱼幼胚为材料研究了不同剂量和不同剂量率的60Coγ辐射对其胚胎发育的影响。结果表明,0.5~1.0Gy的辐射能加快胚胎发育的进程,但最终孵化率却很低,即超敏(HRS)现象,而2.0~4.0Gy为引起增强的辐射抗性(IRR)阶段。在相同剂量和剂量率下,处于4~8细胞期的胚胎存活率比多细胞期和囊胚早期高,而畸形率低。当以5.0Gy的剂量辐射时,剂量率小于1.0Gy/min的慢辐射对胚胎的危害大于较高剂量率(1.0~2.0Gy/min)的快辐射。     

城市土壤氡浓度和γ辐射及其特征的研究——以金华市为例

城市土壤中的氡和γ辐射对人体具有较强的内辐射和外辐射,危害人类健康。本文以金华市为例,通过不同功能区城市土壤氡浓度和γ辐射的调查与监测,探讨城市土壤氡浓度和γ辐射剂量率及其分异特征。结果表明,金华城市土壤氡浓度较低,平均值为6789 Bq m-3,低于世界土壤氡浓度平均值。高值区主要分布在城市绿地、硬盖层边缘及市中心地带,主要与城市绿地、硬盖层边缘氡较易析出和人为污染有关。γ辐射剂量率介于0.09~0.21μSv h-1之间,明显高于中国平均值,这与金华市区北部的江绍深断裂带造成该区γ辐射剂量率整体偏高有关。而在发展历史较早、受人为影响较大的金华江南部城区,人为因素对土壤γ辐射起着主导作用。另外,水域对γ辐射有一定的屏蔽作用。     

太阳辐射减弱对冬小麦叶片光合作用膜脂过氧化及同化物累积的影响

为了探究气溶胶的太阳辐射减弱效应对农作物叶片生理特性及同化物累积的影响,以扬麦13为供试材料,在大田试验条件下系统研究了不同辐射减弱处理（100%、60%、40%、20%、15%）对冬小麦叶片光合作用、膜脂过氧化水平和同化物积累的影响。结果表明：太阳辐射减弱至自然光的60%-15%时,冬小麦叶片净光合速率减少15.8%-70.1%,光合色素的含量（叶绿素a、b和类胡萝卜素）显著提高,其中叶绿素b含量的增加最明显。太阳辐射减弱会抑制冬小麦叶片膜脂过氧化程度,减少细胞膜透性,且辐射减弱的程度越高,影响越大。当太阳辐射为自然光的60%-15%时,冬小麦叶片的可溶性糖含量比对照降低了32.22%-76.45%,可溶性蛋白含量降低了19.02%-48.12%,但总游离氨基酸含量比对照增加了47.46%-177.87%。上述结果表明,太阳辐射减弱后会减弱冬小麦光合作用,增加光合色素含量,抑制膜脂过氧化程度,从而导致作物体内同化物的累积受阻,糖类及蛋白质的含量显著降低,必然会影响作物的产量及品质形成。     

酸雨对黄棕壤的致酸作用与对小麦幼苗膜脂过氧化水平的影响

通过模拟酸雨淋洗土壤,造成了土壤酸化和盐基流失。将小麦幼苗栽培于由酸雨致酸的土壤上,导致小麦幼苗的膜脂过氧化水平提高。其中致酸土壤对根系膜脂过氧化水平的影响大于对叶片膜脂过氧化水平的影响。     

γ射线慢照射大豆苗期植株的效果

本用＾６０Ｃｏγ射线慢照射大豆苗期植株，研究其效果，结果表明，慢照射对Ｍ１代（当代）大豆植株的生长发育和籽粒产量有明显的抑制作用，不同剂量，以及同一剂量的不同剂量率间，对株高，每株荚数，叶片的长宽比等性状的影响不同，而且出现种子急性照射从未有过的变化，如出现１、２、４小叶的复叶，２个以上的多生长点，Ｍ２代幼苗出现１片３片真叶或子叶，且子叶连体或皱折，小剂量率的辐射效果大于大剂量率。苗期慢照射可以     

塑料大棚内辐射分量的日变化特点

本文根据塑料大棚内外各辐射分量的实测资料,计算了闭膜和揭膜两种处理条件下棚内外直接辐射、散射辐射、总辐射、辐射平衡及逆辐射的日变化值,并分析了辐射分量的某些日变化特点.     

铈对UV-B胁迫下大豆幼苗光合原初反应的影响

用水培法研究了Ce（Ⅲ）对紫外辐射（UV-B,280～320nm）胁迫下大豆幼苗光合原初反应的影响。结果表明,20mg·L-1CeCl3能有效减缓紫外辐射（T1/3.34kJ·m-2和T2/11.76kJ·m-2）胁迫所导致的叶绿素与类胡萝卜素含量减少、光能转换效率（Fv/Fm）及传递能力（Fv/F0）降低,且对低剂量胁迫的调控效果优于高剂量,即以上指标Ce＋T1〉T1,Ce＋T2〉T2,Ce＋T1〉Ce＋T2。从光合原初反应的能量分配看,Ce（Ⅲ）能促使大豆叶片吸收光能的总量增加,加快内囊体膜上光电的转换和电子的传递,降低UV-B辐射伤害而导致的过剩激发能积累,从而消除过剩激发能诱发的膜脂过氧化对光合器官的潜在威胁。     

利用昆虫辐射不育技术防治光肩星天牛的可行性

利用昆虫辐射不育技术防治光肩星天牛的适照时期为羽化后7－10d，适宜的辐照剂量为70－90Gy，剂量率为1.5Gy/min。田间纱笼释放试验表明，释放比为5：1可压低野生虫口数量。利用昆虫不育技术防治光肩星天牛的难点是人工饲养。     

γ辐照对鸡枞菌保鲜的研究

以野生鸡枞菌子实体为供试材料 ,经γ射线 0、0 2 5、0 5和 1kGy的剂量辐照后 ,在 1 4℃打孔自发气调储存。结果表明。辐照抑制了鸡枞菌膜脂的过氧化过程 ,保持了膜结构的完整性 ,延缓了鸡枞菌的衰老过程。其中 0 5kGy辐照处理可得到较好的储藏效果。     

Antioxidant activities of phenolic acids on ultraviolet radiation-induced erythrocyte and low density lipoprotein oxidation

The exposure of mammalian cells to UV light induces various deleterious responses. Some of the major harmful effects are DNA damage, cell membrane peroxidation, systemic immune suppression, and aging acceleration. Reactive oxygen species and free radicals are believed to be largely responsible for some of the deleterious effects of UV upon cells. Typical administration of antioxidants has recently proved to represent a successful strategy for protecting the cells against UV-mediated oxidative damage. The objective of this study was to investigate the inhibitory effect of phenolic acids (caffeic acid, ferulic acid, gallic acid, and protocatechuic acid) on oxidative damage in human erythrocytes and low-density lipoprotein (LDL) induced by UVB radiation. The results revealed that the thiobarbituric acids reactive substances induced by UVB were decreased from 2.78 to 0.12-0.89 nmol MDA/mg protein in erythrocyte ghost and from 0.72 to 0.14-0.43 nmol MDA/mg protein in LDL by the addition of phenolic acids (100 muM). Caffeic acid, ferulic acid, and gallic acid exhibited over 85 and 60% inhibitory effect toward UVB-induced oxidation in erythrocytes and LDL, respectively. Phenolic acids, especially gallic acid, could maintain the normal glutathione levels and glutathione peroxidase activity in hemolysate from erythrocytes that were exposed to UVB radiation in comparison with untreated control. The results indicate that the antioxidant activities of caffeic acid and ferulic acid play a potential role in protection against UVB oxidative damage to human erythrocytes and LDL.     

辐照山茶扦插生根特性研究

以12个山茶种和品种的嫩枝插条为材料,对60Co辐照山茶扦插生根特性进行了研究。结果表明,山茶扦插成活率在辐照剂量为5、10或15Gy时升高,部分高于对照,在20、25Gy时明显降低,且远低于对照。辐照的山茶扦插生根的根数和长度不完全一致,随剂量升高呈先升高再降低的趋势或波动性变化;5~15Gy为适宜辐照剂量,在此范围内,平均根数、平均根长和最长根长均达最大值,且高于对照。     

γ辐照对草菇保鲜及其生理机制的研究

以草菇V84 子实体为供试材料,用60 Co γ射线0-8 、1-2 和1-6kGy 辐照,在16 ℃下打孔自发气调贮藏,结果表明,在一定的范围内,辐照抑制了膜脂过氧化过程,保持了膜结构的完整性,因而延缓了草菇的衰老进程,延长了贮藏保鲜期。0-8kGy 辐照处理将草菇的贮藏保鲜期延至6d 。     

Antioxidative effect of kaempferol and its equimolar mixture with phenyltin compounds on UV-irradiated liposome membranes

The work investigates the possibility of the protective action of kaempferol on phosphatidylcholine liposome membranes exposed to the pro-oxidative action of diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT) induced by UV radiation (lambda = 253.7 nm). The concentrations of kaempferol and its equimolar mixtures with DPhT and TPhT were determined so that they induce 50% inhibition in oxidation of liposomes irradiated with UV. They are 11.6, 10.0, and 4.5 microM/L, which constitute the following sequence of antioxidative activity: kaempferol/triphenyltin > kaempferol/diphenyltin > kaempferol. This relationship is confirmed by the results on the antiradical ability of kaempferol and its mixtures with DPhT and TPhT toward the free radical 2,2-diphenyl-1-picrylhydrazyl. Similar sequences obtained in both studies suggest a possible mechanism of the antiradical action of the mixtures as free radical scavengers. Kaempferol's ability, then documented, to form complexes with phenyltins indicates (a) a possible way to liquidate the peroxidation caused by the free radical forms of phenyltins and (b) the stabilizing role of chelating in the antioxidative action of the kaempferol/phenyltins. The differentiation in the action of the compounds studied may, among others, result from different localizations in the liposome membrane, which is indicated by the results of the fluorometric studies.     

Evaluation of antioxidative activity of extracts from a brown seaweed,Sargassum siliquastrum

Antioxidative activities of the extracts from Sargassum siliquastrum were determined using the inhibition of red blood cell (RBC) hemolysis induced by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) radicals, suppression of lipid peroxidation using rat brain homogenate, and scavenging activity of superoxide radicals. The dichloromethane fraction isolated from the methanol crude extract by differential solvent extractions exhibited the strongest antioxidant activity in both RBC hemolysis and lipid peroxidation assays. This fraction was further fractionated into four subfractions F1-F4 by silica gel column chromatography. F1 was found to be most effective in protecting RBC against AAPH radicals and in inhibiting lipid peroxidation. On the basis of thin-layer chromatography and UV and IR spectra analyses, all subfractions contained phenolic compounds. However, there was no correlation between the above antioxidant potency and total phenolic compounds estimated by using the Folin-Ciocalteau method.     

Quantitative analysis of beta-sitosterol oxides induced in vegetable oils by natural sunlight, artificially generated light, and irradiation

UV radiation is able to induce lipid peroxidation. Photooxidation-induced beta-sitosterol oxides were monitored in four vegetable oils exposed to sunlight for 10, 20, and 30 days during May 2005 (northeastern France), exposed to artificial light generated by a high-pressure Hg lamp for 21, 42, and 63 h at room temperature, and exposed to a 10 MeV electron beam at 0.93, 2.69, and 9.30 kGy at 8 degrees C. Quantification was performed by capillary gas chromatography-mass spectrometry according to the total ion current mode and using a reconstructed ion trace chromatogram with specific ion fragments. Sunlight induced the formation of higher amounts of oxides than UV light, while no significant oxidizing effect was observed with electron beam irradiation. However, data suggested that the amount of the main oxides formed was strongly dependent on the dose rate (length of exposure). Accordingly, shorter but more intense treatments had lower oxidizing effects.     

SUGAR CANE BORER CONTROL THROUGH F-1 ST ERILIZATION

<正> To induce sterilization into the F—l generation,pupae of the sugar-cane borer Diatraea saccharalis(F.)were irradiated at the age of six days.The radiation source was a Gammabeam 650 Cobalt-60 irradiator.The pu-pae were irradiated at the dose rate of 340 kGy per hour,at O(control),50,100,150,200,250,300,350,400,450,and 500 Gy doses,The hatching     

快中子辐照对蝴蝶兰离体茎段生理特性的影响

为了探究蝴蝶兰对快中子辐照注量的耐受性,利用快中子脉冲堆对蝴蝶兰Phalaenopsis Taisuco Firebird和Phalaenopsis Neyshanguniang的组培苗茎段进行辐照处理,研究了不同辐照注量对植株抗氧化酶活性、渗透调节物质和膜脂过氧化作用的影响。结果表明,茎段形成的叶片组织内过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化歧化酶(SOD)活性,随着辐照注量的增加均呈现先升高后降低的趋势。较低注量(300×10~8n·cm~(-2))辐照促进抗氧化酶活性增强,提高蝴蝶兰茎段的抗辐射能力;高注量(2 500×10~8n·cm~(-2))辐照显著抑制抗氧化酶活性,造成蝴蝶兰茎段损伤。快中子辐照注量与可溶性蛋白质含量呈极显著负相关(r=-0.734,r=-0.669,P0.01),低注量辐照促进可溶性蛋白质合成代谢,与丙二醛(MDA)含量呈极显著正相关(r=0.929,r=0.926,P0.01),高注量辐照会加剧膜脂过氧化作用。Taisuco Firebird茎段比Neyshanguniang茎段更易受快中子辐照的影响。本研究结果为花卉快中子辐照诱变育种研究提供了一定的理论依据和技术参考。