干旱胁迫对锦灯笼种子萌发及幼苗生理特性的影响

以锦灯笼种子为试材,用3%、5%、8%和10%4个浓度的PEG-6000溶液模拟不同的干旱胁迫条件,研究锦灯笼种子萌发情况和幼苗生理特性,以期了解其抗旱性。结果表明:1)随着PEG-6000浓度的加大,锦灯笼种子的发芽率和发芽势先增加后减少,浓度为5%时最大,株高也是在胁迫浓度为5%时达到最高,这说明一定程度的干旱胁迫可以促进种子萌发及幼苗生长。2)丙二醛含量、可溶性糖含量和电导率随着PEG-6000浓度的增加表现为持续上升的趋势,过氧化物酶(POD)活性则呈现先上升后降低的趋势。     

氯化胆碱对烟草植株生长的促进效应

对烟草喷施不同浓度（０，５０，２００，３００，５００和１０００ｍｇ·Ｌ－１）的氯化胆碱（ＣＣ）后，可提高烟草的株高，尤其对茎粗生长、叶数和叶面积等有明显的促进作用。ＣＣ对增强烟草苗期根系活力和提高苗期的抗寒性也有明显作用。其中以喷施２００和３００ｍｇ·Ｌ－１的ＣＣ者对烟草生长的促进效果最大。     

干旱胁迫与抗蒸腾剂对喜树几项生理指标及喜树碱含量的影响

经过12d的干旱胁迫，喜树叶内Fpro和MDA含量分别升高了46．7％和19．06％，是同期对照的138．93％的117％；Pn降为负值；Tr和Sc显著下降，降低幅度分别为58．28％和75％；且随着胁迫时间的延长，变化幅度逐步增大。抗蒸腾剂可有效地缓解胁迫对喜树的不良影响。短期干旱胁迫可使叶内喜树碱的含量明显提高，在生产中可由此而提高喜树碱的产量。     

Effects of Ammonium Nitrate and Monosodium Glutamate in Waste Water on the Growth,Antioxidant Activity,and Nitrogen Assimilation of Lettuce (Lactuca sativa L.)

It has been hypothesized that the uptake of organic as opposed to inorganic nitrogen compounds found in wastewater can be properly substituted for plant nutrients. The objective of this study was to compare effects of applying monosodium glutamate wastewater (MGW) and ammonium nitrate (NH₄NO₃) (AN) on nitrogen metabolism and growth of lettuce. The results showed that while NH₄NO₃ (AN), NO₃^-, nitrite content and NR activity increased the protein content of lettuce. Applying MGW with a high concentration of 17 amino acids and macro- and microelements improved the fresh weights of shoot and root as well as the protein content of lettuce. Antioxidant activities were not affected by AN and MGW, and their interaction effects only increased POD after 8 weeks. In conclusion, substituting a portion of the chemical fertilizers with MGW improved lettuce growth, but did not increase NO₃^- accumulation in leaves.     

Hydrogen peroxide localization and antioxidant status in the recovery of apricot plants from European Stone Fruit Yellows

Hydrogen peroxide (H₂O₂) localization and roles of peroxidases, malondialdehyde and reduced glutathione were compared in leaves of apricot (Prunus armeniaca) plants asymptomatic, European Stone Fruits Yellows (ESFY)-symptomatic and recovered. Nested PCR analysis revealed that Candidatus Phytoplasma prunorum, is present in asymptomatic, symptomatic and recovered apricot trees, confirming previous observations on this species, in which recovery does not seem to be related to the disappearance of phytoplasma from the plant.H₂O₂was detected cytochemically by its reaction with cerium chloride, which produces electron-dense deposits of cerium perhydroxides. H₂O₂was present in the plasmalemma of the phloem cells of recovered apricot plant leaves, but not in the asymptomatic or symptomatic material. Furthermore, by labelling apricot leaf tissues with diaminobenzidine DAB, no differences were found in the localization of peroxidases.Protein content in asymptomatic, symptomatic and recovered leaves was not significantly different from one another. In contrast, guaiacol peroxidase activity had the following trend: symptomatic > recovered > asymptomatic, whereas reduced glutathione content followed the opposite trend: asymptomatic > recovered > symptomatic. Moreover, no differences were observed in malondialdehyde concentrations between asymptomatic, symptomatic and recovered leaves. The overall results suggest that H₂O₂ and related metabolites and enzymes appear to be involved in lessening both pathogen virulence and disease symptom expression in ESFY-infected apricot plants.     

Cytotoxic, cytoprotective and antioxidant effects of isolated phenolic compounds from fresh ginger

Twenty-nine phenolic compounds were isolated from the root bark of fresh (Yunnan) ginger and their structures fully characterized. Selected compounds were divided into structural categories and twelve compounds subjected to in-vitro assays including DPPH radical scavenging, xanthine-oxidase inhibition, monoamine oxidase inhibition, rat-brain homogenate lipid peroxidation, and rat pheochromocytoma PC12 cell and primary liver cell viability to determine their antioxidant and cytoprotective properties. Isolated compounds were also tested against nine human tumor cell lines to characterize anticancer potency. Several diarylheptanoids and epoxidic diarylheptanoids were effective DPPH radical scavengers and moderately effective at inhibiting xanthine oxidase. An enone–dione analog of 6-shogaol (compound 2) was isolated and identified to be most effective at protecting PC12 cells from H₂O₂-induced damage. Almost all tested compounds inhibited lipid peroxidation. Three compounds, 6-shogaol, 10-gingerol and an enone-diarylheptanoid analog of curcumin (compound 6) were identified to be cytotoxic in cell lines tested, with KB and HL60 cells most susceptible to 6-shogaol and the curcumin analog with IC₅₀ < 10 μM. QSAR analysis revealed cytotoxicity was related to compound lipophilicity and chemical reactivity. In conclusion, we observed distinct compounds in fresh ginger to have biological activities relevant in diseases associated with reactive oxygen species.     

Response of Osmotic Regulation Substance Content and Protective Enzyme Activities to Shading in Leaves of Different Rice Genotypes

Effects of shading at the flowering and grain filling stages on osmotic regulation substance content and protective enzyme activities in the leaves of different rice genotypes (e.g.,IIyou 498,Gangyou 188,Dexiang 4103,Gangyou 527 and Chuanxiang 9838) were investigated.The results showed that the malondialdehyde content of Gangyou 188 significantly increased under shading,whereas those of IIyou 498,Dexiang 4103,Gangyou 527 and Chuanxiang 9838 showed no significant differences compared to the control.The soluble sugar content significantly decreased in IIyou 498,Gangyou 188,Dexiang 4103 and Chuanxiang 9838,whereas it did not significantly increase in Gangyou 527 under the weak light conditions (shading).Moreover,the soluble protein content in the leaves of different genotypes tended to decrease under shading.Further,the protective enzyme activities in the leaves varied in different rice genotypes under the shading treatment.Based on the osmotic regulation substance content and the protective enzyme activities in the leaves of different rice genotypes,it was concluded that Gangyou 188 and Gangyou 527 had strong abilities to adapt to the low light conditions.In addition,the mechanism of damage to rice leaves in different genotypes under shading was discussed.     

Oxidant related biochemical traits are significant indices in triticale grain yield under drought stress condition

Two separate experiments, one as drought stress conditions and the other one as the normal irrigation conditions based on randomized complete block design with three replications were implemented to examine 20 triticale (Triticoseclae wittamack X) genotypes of which 19 genotypes have recently been generated by crossing different parent lines and the other one was Javaniloo, a common cultivar. Based on the results of different statistical techniques and comparing relationships among traits for normal irrigation and stress condition, enzymatic antioxidant could be used as criteria for screening tolerant genotypes of triticale. On the other hand, it is pointed out that superoxide dismutase are the most important criteria to achieve higher tolerant genotypes through indirect selection. Furthermore, hydrogen peroxide and malondialdehyde content having high relationship with rain yield are also the different possible criteria for screening triticale genotypes for water stress conditions in which genotypes with lower content of these traits could be screened.     

Relationships between ultimate pH and antioxidant enzyme activities and gene expression in pork loins

Ultimate pH (pH_u) is a major determinant factor of meat quality. In this study, we investigated the effects of pH_u on the muscle antioxidant capacity, and the relationship between pH_u and muscle antioxidant capacity of pigs. A total of 137 pigs from three pig breeds with the same feeding condition were slaughtered and used to measure the pH_u, superoxide dismutase (SOD), glutathione peroxidase (GSH‐PX), total antioxidant capacity (T‐AOC), and malondialdehyde (MDA) content, and gene expression of SOD1 and GPX4. Loins from 137 pigs of three breeds were classified based on pH_u into three groups: low (L‐pH: ≤5.50), intermediate (I‐pH: 5.51‐5.90), and high (H‐pH: ≥5.91). A majority of loins (47.5%–52%) were classified into the intermediate group. The results suggested that the pH_u value was correlated with the activity of SOD, GSH‐PX, T‐AOC, and MDA, and gene expression of SOD1 and GPX4 in all pigs. In addition, our results also indicated a linear relationship between the pH_u value and antioxidant traits. The pH_u value accounted for 23%–40% of the variation in the antioxidant traits. These results suggested that increased pH_u reduce the lipid peroxidation, and also indicated that pHu may be a key factor explaining the variation in the activity of antioxidant enzymes and gene expression in pork loins.     

卫星搭载处理对辣椒萌发过程中抗氧化酶活性的影响

测定经卫星搭载后的辣椒种子萌发过程中抗氧化酶的活性。结果表明:辣椒种子经卫星搭载处理后,其发芽势和发芽率分别比对照提高了3.5%和5.3%;在萌发过程中,可溶性蛋白质MDA含量低于地面对照,但SOD活性高于对照;卫星搭载的种子在萌发13d的幼苗体内SOD、G-POD、APX和CAT活性分别较对照提高了14.29%、25.23%、1.84%和21.52%。表明卫星搭载处理提高了辣椒种子和幼苗体内抗氧化酶活性,对萌发初期保护膜系统的修复具有重要的意义。