Genotypic Differences in Antioxidative Stress and Salt Tolerance of Three Poplars Under Salt Stress

To evaluate genotypic difference in antioxidative ability and salt tolerance in poplars, the authors investigated the effects of increasing content of soil NaCl on salt concentration in leaves, superoxide dismutase (SOD) and peroxidase (POD) activities, malondialdehyde (MDA) content, and membrane permeability (MP) in Populus euphratica Oliv., P. popularis “35–44,” and P. × euramericana cv. I-214 (hereafter abbreviated as P. cv. I-214). Na⁺ and Cl⁻ concentrations in leaves of P. popularis increased markedly over the increase of the duration of exposure to salinity, and culminated after 28 days of salt stress. SOD and POD activities declined correspondingly, followed by significant increases of MDA and MP, and leaf injury was finally observed. Compared with P. popularis, leaf Na⁺ and Cl⁻ in P. cv. I-214 exhibited a trend similar to P. popularis, but a lower salt-induced increase of MDA and permeability was observed and lighter leaf necrosis occurred. In contrast to P. popularis and P. cv. I-214, SOD and POD activities in P. euphratica leaves increased rapidly at the beginning of salt stress with a light soil NaCl concentration of 58.5 mmol/L. Furthermore, salt ion concentration, MDA content, and MP in P. euphratica leaves did not increase significantly during 28 days of increasing salt stress. Therefore, the increase in MP in P. popularis and P. cv. I-214 had a close relationship with a salt buildup in leaves under increasing salt stress. Salt-induced declines of SOD and POD activities might accelerate lipid peroxide and consequently resulted in ion leakage. P. euphratica rapidly activated antioxidant enzymes after the onset of salt stress, which might reduce the accumulation of reactive oxygen species and the subsequent acceleration of lipid peroxide. P. euphratica leaves exhibited a higher capacity to exclude salt in a longer period of increasing salinity, thus limited salt-induced lipid peroxide and MP, which contributed to membrane integrity maintenance and salt tolerance of P. euphratica. Translated from Journal of Beijing Forestry University, 2005, 27(3) (in Chinese)     

Selenium and vitamin E, natural antioxidants, protect rat cerebral cortex against dimethoate-induced neurotoxicity

Pesticides have been used in agriculture to enhance food production by eradicating unwanted insects and controlling disease vectors, nevertheless occupational exposure to high levels of these compounds can lead to neurodegenerative disorders, characterized by serious oxidative and neurotoxic effects. However, there is a lack of consensus as to which determinations are best used to quantify future risks arising from xenobiotic exposure and natural antioxidant interventions. Our study aims to determine the potential ability of selenium and/or vitamin E, used as nutritional supplements, to alleviate oxidative stress in cerebral cortex tissue induced by dimethoate, an organophosphorus pesticide. Adult Wistar rats were exposed either to dimethoate (0.2 g/L of drinking water), dimethoate + selenium (0.5 mg/kg of diet), dimethoate + vitamin E (100 mg/kg of diet), or dimethoate + selenium + vitamin E, for 30 days. Exposure to dimethoate increased malondialdehyde levels, protein carbonyl groups and advanced oxidation protein products, while Na⁺K⁺-ATPase, acetylcholinesterase and butyrylcholinesterase activities decreased in the cerebral cortex. An increase in glutathione peroxidase, superoxide dismutase and catalase activities and a decrease in glutathione, non-protein thiols and vitamin C levels were observed. Administration of selenium and/or vitamin E through the diet in dimethoate treated rats ameliorated the biochemical parameters cited above. The histological findings confirmed the biochemical results. The model of this study that we employed characterized the relationships between dimethoate-induced neurotoxicity and its alleviation by natural antioxidants like selenium and vitamin E. These elements may be considered beneficial for the protection of cerebral cortex against injury induced by dimethoate.     

芝芪菌素对蛋鸡抗氧化功能的影响

通过检测鸡蛋蛋黄中丙二醛(MDA)含量和蛋清与蛋黄中蛋白质含量,以探讨芝芪菌素对蛋鸡抗氧化功能和蛋品质的影响.选择140日龄罗曼商品代褐壳蛋鸡960只,采取单因子完全随机设计,随机分为4组,分别按0.2%、0.35%、0.5%3个剂量将芝芪菌素添加到蛋鸡日粮中,不添加芝芪菌素设置为对照组.饲养180、210、240 d...     

Olive leaves (Olea europea L.) and α‐tocopheryl acetate as feed antioxidants for improving the oxidative stability of α‐linolenic acid‐enriched eggs

Ninety‐six brown Lohmann laying hens were equally assigned into four groups with six replicates. Hens within the control group were fed a corn–soybean‐based diet supplemented with 4% linseed oil. Two other groups were given the same diet further supplemented with 5 or 10 g ground olive leaves/kg feed, while the diet of the fourth group was further supplemented with 200 mg α‐tocopheryl acetate/kg. Supplementing diets with olive leaves had no effect on egg production, feed intake and egg traits. Eggs collected 28 days after feeding the experimental diets were analysed for lipid hydroperoxides and malondialdehyde (MDA) content, fatty acid profile, α‐tocopherol concentrations and susceptibility to iron‐induced lipid oxidation. Olive leaves were also analysed for total and individual phenolics, and total flavonoids, whereas their antioxidant capacity was determined using both the DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) and ABTS (2,2‐azinobis3‐ethylbenzothiazoline‐6‐sulphonic acid) radical scavenging activity assays. Results showed that neither α‐tocopheryl acetate nor olive leaves supplementation exerted (p > 0.05) any effect on the fatty acid composition of n‐3 eggs. Supplementing the diet with 5 g olive leaves/kg had no (p > 0.05) effect on the hydroperoxide levels of n‐3 eggs, while supplementing with 10 g olive leaves/kg or 200 mg α‐tocopheryl acetate/kg, the lipid hydroperoxide levels were reduced (p ≤ 0.05) compared to control. However, although hydroperoxides were reduced, MDA, a secondary lipid oxidation product, was not affected (p > 0.05). Iron‐induced lipid oxidation increased MDA values in eggs from all groups, the increase being higher (p ≤ 0.05) in the control group and the group supplemented with 5 g olive leaves/kg. The group supplemented with 10 g olive leaves/kg presented MDA values lower (p ≤ 0.05) than the control but higher (p ≤ 0.05) than the α‐tocopheryl acetate group, which presented MDA concentrations lower (p ≤ 0.05) than all other experimental diets at all incubation time points.     

添加KCl对高盐胁迫下红豆草生长及生理特性的影响

为探究K^+对高盐胁迫下红豆草生长及相关生理指标的影响,在高盐胁迫(100 mmol·L^-1 NaCl)下添加不同浓度(5、10、25和50 mmol·L^-1)KCl对4周龄幼苗处理7d后进行测定。结果表明,高盐胁迫显著抑制了红豆草幼苗的生长;然而,添加不同浓度KCl明显减轻了高盐胁迫对幼苗生长的抑制作用。高盐胁迫下,随着KCl浓度的升高,红豆草幼苗的鲜重、干重、组织含水量和叶绿素含量逐渐增加,当浓度为25 mmol·L^-1时达到最大值,随后有所降低;叶和根中的Na^+浓度逐渐降低,而K^+浓度和K^+/Na^+呈逐渐升高趋势;脯氨酸、可溶性糖和可溶性蛋白含量在KCl浓度为25 mmol·L^-1时达到峰值,而后下降;丙二醛(MDA)含量、细胞壁、细胞质和液泡转化酶活性逐渐减小,而超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物(APX)、蔗糖合成酶(SS)及蔗糖磷酸合成酶(SPS)活性、蔗糖和葡萄糖含量呈逐渐增加趋势。添加K^+可通过维持植株体内K^+、Na^+稳态平衡、提高抗氧化酶活性和增强蔗糖的合成与积累,来减轻高盐胁迫对红豆草幼苗的毒害作用。     

Short‐term effects of T‐2 toxin exposure on some lipid peroxide and glutathione redox parameters of broiler chickens

The purpose of this study was to investigate the short‐term effects of T‐2 toxin exposure (3.09 mg/kg feed) on lipid peroxidation and glutathione redox system of broiler chicken. A total of 54 Cobb 500 cockerels were randomly distributed to two experimental groups at 21 days of age. Samples (blood plasma, red blood cell, liver, kidney and spleen) were collected every 12 h during a 48‐h period. The results showed that the initial phase of lipid peroxidation, as measured by conjugated dienes and trienes in the liver, was continuously, but not significantly higher in T‐2 toxin‐dosed birds than in control birds. The termination phase of lipid peroxidation, as measured by malondialdehyde, was significantly higher in liver and kidney as a result of T‐2 toxin exposure at the end of the experimental period (48th hour). The glutathione redox system activated shortly after starting the T‐2 toxin exposure, which is supported by the significantly higher concentration of reduced glutathione and glutathione peroxidase activity in blood plasma at 24 and 48 h, in liver at 12, 24 and 36 h, and in kidney and spleen at 24 h. These results suggest that T‐2 toxin, or its metabolites, may be involved in the generation of reactive oxygen substances which causes an increase in lipid peroxidation, and consequently activates the glutathione redox system, namely synthesis of reduced glutathione and glutathione peroxidase.     

离体条件下盐胁迫对马铃薯试管苗叶绿素含量,脯氨酸累积和抗氧化酶活性的影响

离体条件下,研究了2个马铃薯品种在0～80 mmol NaCl胁迫下的试管苗生长、叶绿素含量、脯氨酸和丙二醛含量及氧化酶活性的反应.2品种苗高随盐浓度增加及培养时间的延长而显著降低.与品种紫花白相比,同一盐浓度下静石2号在苗鲜重、根长和根数等方面受抑制程度更强.盐胁迫培养3周后,试管苗叶片中叶绿素a,b与总量及类胡萝卜素含量在40～80 mmol高盐浓度下显著降低.两个品种试管苗中脯氨酸和丙二醛含量随盐浓度的增加而增加,而静石2号中脯氨酸和丙二醛的累积量和累积率都高于紫花白,表明在盐胁迫下静石2号膜脂过氧化程度相对较高.2品种SOD和POD活性均在低盐浓度(20 mmol)下显著增加而高盐浓度下降低.离体条件下,紫花白试管苗呈现出比静石2号高的SOD、POD活性以及较强的耐盐能力,表明其具有进一步在田间进行耐盐基因型筛选的必要性.     

两种菊芋耐盐差异研究

To explore genetic variability for two Jerusalem artichoke (Helianthus tuberosus) cultivars, N1 (the sixth-generation cultivated with 75% seawater irrigation for six years) and N7 (a general variety), a experiment was conducted to study the changes in physiological attributes under different concentrations (0%, 10% and 25% of seawater concentration in greenhouse and 0%, 30% and 50% of seawater concentration in the field) of seawater salinity stress. In the greenhouse experiment, decreases of dry growth rate, but increases of dry matter percentage and membrane injury occurred in both the genotypes at 10% and 25% seawater treatments, although lesser cell membrane damage was observed in N1 than N7. N1 accumulated greater contents of Na⁺, Cl^-, soluble sugar and proline in leaves compared with N7. In the field experiment, the yields of shoot, root and tuber, and the contents of total-sugar and inulin in tubers of N1 were higher than those of N7. Lesser degree of salt injury in N1 indicated that the relatively salt-tolerant cultivar had higher K⁺/Na⁺ ratio, lower Na⁺/Ca²⁺ ratio, and the salt-induced enhancement of osmotic adjustment.