Oxidative stress response after prolonged exposure of domestic rabbit to a lower dosage of extracted microcystins

Oxidative stress response after prolonged exposure to a low dose of microcystins (MCs) was studied in liver, kidney and brain of domestic rabbits. Rabbits were treated with extracted MCs (mainly MC-LR and MC-RR) at a dose of 2 MC-LReq. mu g/kg body weight or saline solution every 24 h for 7 or 14 days. During the exposure of MCs, increase of lipid peroxidation (LPO) levels were detected in all the organs studied, while antioxidant enzymes responded differently among different organs. The enzyme activities Of Superoxide dismutase (SOD). catalase (CAT) and glutathione reductase (GR) in liver decreased in the MCs treated animals. In brain, there were obvious changes in glutathione peroxidase (GPx) and GR, while only CAT was obviously influenced in kidney. Therefore, daily exposure at a lower dosage of MCs, which mimicked a natural route of MCs. could also induce obvious oxidative stress in diverse organs of domestic rabbits. The oxidative stress induced by MCs in brain was as serious as in liver and kidney, suggesting that brain may also be a target of MCs in mammals. And it seems that animals may have more time to metabolize the toxins or to form an adaptive response to reduce the adverse effects when exposed to the low dose of MCs. (C) 2008 Elsevier B.V. All rights reserved.

Effects of dietary ascorbic acid supplementation on the growth performance, immune and stress response in juvenile Leiocassis longirostris Gunther exposed to ammonia

This experiment was designed to investigate the effect of dietary supplemental ascorbic acid (AA) on the feed intake, growth, serum lysozyme, hepatic superoxide dismutase (SOD) and handling stress response in Chinese longsnout catfish (Leiocassis longirostris Gunther) exposed to three levels of unionized ammonia nitrogen (UIA-N). Juvenile Chinese longsnout catfish were reared in 54 fibreglass tanks with a 3 x 3 factorial design treatment consisting of three supplemental AA levels in ascorbyl 2-monophosphate (38, 364 and 630 mg AA equivalent kg(-1) diet) and three UIA-N concentrations [0.004 (the control), 0.037 and 0.292 mg L-1]. The fish were sampled on the 11th, 32nd and 60th day. On the 62nd day, the remaining fish were subjected to an acute stress by being held in a dipnet out of water for 60 s, and sampled at 30 min post handling. The results showed that the specific growth rate (SGR) in 32 days significantly decreased with increased water UIA-N (P=0.0476) but was not affected by dietary supplemental AA (P > 0.05). After 60 days, SGR, feeding rate (FR) and feed conversion efficiency (FCE) significantly increased with increased dietary supplemental AA (P < 0.001) while remaining unaffected by water UIA-N (P > 0.05). There was no significant interaction between dietary AA and UIA-N for growth responses (P > 0.05). The serum lysozyme activity on the 11th day and the hepatic SOD activity on the 32nd day were significantly affected at high (0.292 mg L-1) water UIA-N. On the 62nd day, the increase in cortisol resulting from acute stress significantly decreased by higher UIA-N (P=0.038). It is suggested that Chinese longsnout catfish displayed an adaptive response after long-term UIA-N exposure, and AA had beneficial effects on the growth and feed intake of catfish and alleviated the negative effects of chronic ammonia stress. A chronically higher ammonia level shows a tendency to inhibit the cortisol response to another acute stressor.

Comparative proteomic profiles of the hepatopancreas in Fenneropenaeus chinensis response to hypoxic stress

Hypoxia, as one suboptimal environmental condition, can affect the physiological state of shrimp during pond aquaculture. To better understand the mechanism of response to hypoxic stress in Chinese shrimp Fenneropenaeus chinensis, proteome research approach was utilized. Differentially expressed proteins of hepatopancreas in adult Chinese shrimp between the control and hypoxia-stressed groups were screened. By 2-DE analysis, 67 spots showed obvious changes after hypoxia. Using LC-ESI-MS/MS, 51 spots representing 33 proteins were identified including preamylase, arginine kinase, phosphopyruvate hydratase, citrate synthase, ATP synthase alpha subunit, chymotrypsin BI, chitinase, ferritin, C-type lectin receptors, transketolase, formylglutathione hydrolase, formyltetrahydrofolate dehydrogenase, aldehyde dehydrogenase, glutathione peroxidase, cytosolic manganese superoxide dismutase, protein disulfide isomerase, beta-actin, oncoprotem nm23, crustacyanin-Cl and so on. These proteins could be functionally classified into several groups such as proteins related to energy production, metabolism-related proteins, immune-related proteins, antioxidant proteins, chaperones, cytoskeleton proteins and ungrouped proteins. The transcription levels of ten selected genes encode the identified proteins were analyzed by real-time PCR at different sampling times of hypoxia. This study is the first analysis of differentially expressed proteins in the hepatopancreas of shrimp after hypoxia and provides a new insight for further study in hypoxic stress response of shrimp at the protein level.

Enhanced protection against oxidative stress in an astaxanthin-overproduction Haematococcus mutant (Chlorophyceae)

Many unicellular green algae can become yellow or red in various natural habitats due to mass accumulation of a secondary carotenoid, such as lutein, or astaxanthin. The accumulation of secondary carotenoids is generally thought to be a survival strategy of the algae under photo-oxidative stress or other adverse environmental conditions. The physiological role of the carotenoids in stress response is less well understood at the subcellular or molecular level. In this study, a stable astaxanthin overproduction mutant (MT 2877) was isolated by chemical mutagenesis of a wild type (WT) of the green microalga Haematococcus pluvialis Flotow NIES-144. MT 2877 was identical to the WT with respect to morphology, pigment composition, and growth kinetics during the early vegetative stage of the life cycle. However, it had the ability to synthesize and accumulate about twice the astaxanthin content of the WT under high light, or under high light in the presence of excess amounts of ferrous sulphate and sodium acetate. Under stress, the mutant exhibited higher photosynthetic activities than the WT, based on considerably higher chlorophyll fluorescence induction, chlorophyll autofluorescence intensities, and oxygen evolution rates. Cell mortality caused by stress was reduced by half in the mutant culture compared with the WT. Enhanced protection of the mutant against stress is attributed to its accelerated carotenogenesis and accumulation of astaxanthin. Our results suggest that MT 2877, or other astaxanthin overproduction Haematococcus mutants, may offer dual benefits, as compared with the wild type, by increasing cellular astaxanthin content while reducing cell mortality during stress-induced carotenogenesis.

pkn22 (alr2502) encoding a putative Ser/Thr kinase in the cyanobacterium Anabaena sp PCC 7120 is induced by both iron starvation and oxidative stress and regulates the expression of isiA

In cyanobacteria, the isiA gene is required for cell adaptation to oxidative damage caused by the absence of iron. We show here that a putative Ser/Thr kinase gene, pkn22 (alr2052), is activated by iron deficiency and oxidative damage in Anabaena sp. PCC 7120. A pkn22 insertion mutant is unable to grow when iron is limiting. pkn22 regulates the expression of isiA (encoding CP43') but not of isiB (encoding flavodoxin) and psbC (CP43). Fluorescence measurement at 77 K reveals the absence of the typical signature of CP43' associated with photosystem I in the mutant under iron-limiting conditions. We propose that Pkn22 is required for the function of isiA/CP43' and constitutes a regulatory element necessary for stress response. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Influence of secondary void damage in the matrix material around voids

The mechanism of ductile damage caused by secondary void damage in the matrix around primary voids is studied by large strain, finite element analysis. A cylinder embedding an initially spherical void, a plane stress cell with a circular void and plane strain cell with a cylindrical or a flat void are analysed under different loading conditions. Secondary voids of smaller scale size nucleate in the strain hardening matrix, according to the requirements of some stress/strain criteria. Their growth and coalescence, handled by the empty element technique, demonstrate distinct mechanisms of damage as circumstances change. The macroscopic stress-strain curves are decomposed and illustrated in the form of the deviatoric and the volumetric parts. Concerning the stress response and the void growth prediction, comparisons are made between the present numerical results and those of previous authors. It is shown that loading condition, void growth history and void shape effect incorporated with the interaction between two generations of voids should be accounted for besides the void volume fraction.

Ultraviolet-B exposure induces photo-oxidative damage and subsequent repair strategies in a desert cyanobacterium Microcoleus vaginatus Gom.

Biological soil crusts are important in reversing desertification. Ultraviolet radiation, however, may be detrimental for the development of soil crusts. The cyanobacterium Microcoleus vaginatus can be a dominant species occurring in desert soil crusts all over the world. To investigate the physico-chemical consequences of ultraviolet-B radiation on M. vaginatus, eight parameters including the contents of chlorophyll a, reactive oxygen species, malondialdehyde and proline, as well as the activities of photosynthesis, superoxide dismutase (EC 1.15.1.1), peroxiclase (EC 1.11.1.7) and catalase (EC 1.11.1.6) were determined. As shown by the results of determinations, ultraviolet-B radiation caused decreases both in contents of chlorophyll a and in ratios of variable fluorescence over maximum fluorescence that indicate the growth and photosynthesis of M. vaginatus, besides, increases both in levels of reactive oxygen species and in contents of malondialdehyde and proline, while intensified activities of superoxide dismutase, peroxiclase and catalase reflecting the abilities of enzymatic preventive substances to oxidative stress of the treated cells. Therefore, ultraviolet-B radiation affects the growth of M. vaginatus and leads to oxidative stress in cells. Under ultraviolet-B radiation, the treated cells can improve their antioxidant abilities to alleviate oxidative injury. The change trends of reactive oxygen species, superoxide dismutase, peroxiclase and catalase are synchronous. These results suggest that a balance between the antioxidant system and the reactive oxygen species content may be one part of a complex stress response pathway in which multiple environmental factors including ultraviolet-B radiation affect the Survival of M. vaginatus. (C) 2009 Elsevier Masson SAS. All rights reserved.

Changes in plasma thyroid hormones and cortisol levels in crucian carp (Carassius auratus) exposed to the extracted microcystins

The endocrine response of crucian carp injected intraperitoneally with extracted microcystins (MC) was investigated in this study. Fish were injected intraperitoneally either with 0.75% NaCl (control) and Microcystis extract corresponding to 150 and 600 mu g microcystins per kg body weight. The plasma levels of triiodothyronine (T-3), thyroxine (T-4), free triiodothyronine (FT3), free thyroxine (FT4), and cortisol were determined at 0, 1, 3, 12, 24. and 48 h post-administration of MC-containing extract. Treated fish displayed abnormal behaviors, Such as a startle response and disoriented swimming, as well as changes in ventilation rates. Plasma cortisol concentrations of fish in both dose groups significantly increased after administration of extracted MC and remained high throughout the experiment, which suggested that MC elicited a stress response in treated fish. The profiles of cortisol changes in treated fish appeared to be dose dependent, indicating that fish in the high dose group experienced greater MC-incluced disturbance. Mortality occurred after 12 h in the high dose group. Plasma levels of T-4, T-3, FT4, and FT3 did not vary significantly between the control fish. In contrast to this, fish exposed to MC-containing extract showed significant declines in T-3, FT4, and FT3 levels in a dose-depenclent manner throughout the experiment. Plasma T4 levels, however, did not vary significantly in the low dose group, whereas they decreased significantly it 48 h post injection in the high dose group. This study demonstrates that administration of microcystins-containing extract causes a stress response and reduces the plasma levels of thyroid hormones in crucian carp. These results illustrate that microcystins exerted potent effects on the endocrine system of crucian carp, through activating their hypothalamus-pituitary- interrenal axis and disturbing thyroid function. (c) 2008 Elsevier Ltd. All rights reserved.

Enzyme-linked immunosorbent assay of changes in serum levels of growth hormone (cGH) in common carps (Cyprinus carpio)

The aim of the present study was to purify the common native carp growth hormone (ncGH), produce monoclonal antibodies (mAbs) to common native carp growth hormone (ncGH), and further enhance the sensitivity of enzyme-linked immunosorbent assays (ELISA) for ncGH. Additionally, we investigated changes in serum ncGH levels in carps raised in different environmental conditions. The recombinant grass carp (Ctenopharyngodon idella) growth hormone was purified and used as antigen to immunize the rabbit. The natural ncGH was isolated from the pituitaries of common carp. SDS-PAGE and Western blot utilizing the polyclonal anti-rgcGH antibody confirmed the purification of ncGH from pituitaries. Purified ncGH was then used as an immunogen in the B lymphocyte hybridoma technique. A total of 14 hybridoma cell lines (FMU-cGH 1-14) were established that were able to stably secrete mAbs against ncGH. Among them, eight clones (FMU-cGH1-6, 12 and 13) were successfully used for Western blot while nine clones (FMU-cGH 1-7, 9 and 10) were used in fluorescent staining and immunohistochemistry. Epitope mapping by competitive ELISA demonstrated that these mAbs recognized five different epitopes. A sensitive sandwich ELISA for detection of ncGH was developed using FMU-cGH12 as the coating mAb and FMU-cGH6 as the enzyme labeled mAb. This detection system was found to be highly stable and sensitive, with detection levels of 70 pg/mL. Additionally, we found that serum ncGH levels in restricted food group and in the net cage group increased 6.9-and 5.8-fold, respectively, when compared to controls, demonstrating differences in the GH stress response in common carp under different living conditions.

Identification and characterization of a MBP isoform specific to hypothalamus in orange-spotted grouper (Epinephelus coioides)

Myelin basic protein (MBP), as a major component of the myelin sheath, has been revealed to play an important role informing and maintaining myelin structure in vertebrate nervous system. In teleost, hypothalamus is an instinctive brain center and plays significant roles in many physiological functions, such as energy metabolism, growth, reproduction, and stress response. In comparison with other MBP identified in vertebrates, a smallest MBP is cloned and identified from the orange-spotted grouper hypothalamic cDNA plasmid library in this study. RT-PCR analysis and Western blot detection indicate that the EcMBP is specific to hypothalamus, and expresses mainly in the tuberal hypothalamus in adult grouper. Immunofluorescence localization suggests that EcMBP should be expressed by oligodendrocytes, and the expressing cells should be concentrated in hypothalamus and the area surrounding hypothalamus, such as NPOpc, VC, DP, NLTm, and NDLI The studies on EcMBP expression pattern and developmental behaviour in the brains of grouper embryos and larvae reveal that the EcMBP-expressing cells are only limited in a defined set of cells on the border of hypothalamus, and suggest that the EcMBP-expressing cells might be a subpopulation of oliaodendrocyte progenitor cells. This study not only identifies a smallest MBP isoform specific to hypothalamus that can be used as a molecular marker of oligodendrocytes in fish, but also provides new insights for MBP evolution and cellular distribution. (C) 2007 Elsevier B.V.. All rights reserved.

镉对花生品质影响及胁迫响应机制研究

近年来，我国花生重金属镉超标的现象屡见不鲜，致使花生在我国出口创汇的能力受到了严重影响。因此，本项研究选用北方两种花生－锦花5号和阜花13号为供试材料，采用室外盆栽方式，初步探讨了镉胁迫对花生品质的影响及花生对镉胁迫的响应机制，揭示了花生易富集镉和对镉高耐性的原因。 1．在外源高镉处理下，两品种花生的产量随镉处理浓度的增加而降低；籽实Cd含量均随土壤中Cd含量的增加而显著增加（p＜0.05），在土壤低Cd处理时，花生籽实更易富集Cd；花生受Cd胁迫后，籽实的亮氨酸含量受Cd的影响较为严重；氨基酸组成比例在较低镉处理剂量下未受到影响。 2．受Cd污染的花生籽实，种皮Cd含量较高；蛋白质是络合镉的主要营养部位，而脂肪中镉的含量甚微，研究处理范围内均低于食品中Cd的限量值0.2 mg•kg-1 ；因此供试花生籽实不能作为人体对植物蛋白的来源，但可以作为人体对食用油脂的来源。 3．花生籽实中存在植物螯合肽PC4，它在花生中镉的耐性方面发挥着重要的作用。尽管非蛋白巯基（NPT）、半胱氨酸（Cys）、PC4和脯氨酸（Pro）含量受作物品种和外源镉处理剂量的影响，但它们对籽实中重金属镉的络合发挥着作用。此外，脯氨酸（Pro）还可以作为花生受镉胁迫的生物指示物。

缺铁条件下植物对土壤镉的吸收及胁迫响应机制的研究

本文通过水培试验，盆栽试验研究缺铁条件下对重金属Cd的吸收与积累，供试植物为龙葵、番茄、玉米和小麦，主要考察了缺铁条件下不同Cd浓度处理下，不同植物对重金属Cd的吸收影响，根际环境的变化，根系分泌物的变化，以及植物铁载体分泌率的变化，同时研究了植物在铁缺乏条件下对重金属Cd的抗性机制和胁迫响应机理，得出以下主要结论： 液体培养条件下，营养液进行加铁和缺铁处理，不同Cd浓度处理中，缺铁处理植物的生物量低于相应的加铁处理，富集的Cd高于相应的加铁处理，缺铁处理转移系数与富集系数高于加铁处理。缺铁处理溶液酸碱度低于加铁处理，氧化还原电位高于加铁处理。缺铁处理促进了Cd的吸收和积累，主要是由于缺铁条件下对根系环境产生的变化，有助于植物对Cd的吸收。 液体培养条件下，营养液进行加铁和缺铁处理，不同Cd浓度处理中，基本上缺铁处理植物的根系分泌物中四种有机酸的含量显著高于相应的加铁处理。无论是加铁还是缺铁处理，四种有机酸的分泌量：酒石酸>苹果酸>柠檬酸>乙酸。通过相关分析，加铁处理龙葵与番茄根系分泌物中酒石酸含量与镉含量呈极显著正相关，而缺铁处理的呈极显著负相关，表明番茄与龙葵根系分泌物中酒石酸可以指示缺铁处理对Cd的积累。加铁处理与缺铁处理龙葵与番茄的柠檬酸与Cd积累无相关性。加铁处理与缺铁处理玉米苹果酸与Cd积累无相关性，其他有机酸与之呈现正相关，加铁处理与缺铁处理小麦与四种有机酸均呈现正相关。 液体培养条件下，营养液进行加铁和缺铁处理，不同Cd浓度处理中，缺铁处理植物的叶绿素、可溶性糖含量、SOD、POD和CAT活性低于相应的加铁处理，电导率、可溶性蛋白、脯氨酸和MDA含量高于相应的加铁处理。重金属Cd和缺铁处理导致植物膜脂过氧化作用，主要体现在MDA和细胞质膜膜透性升高，导致植株生物量降低，叶绿素含量降低，导致可溶性糖含量下降。脯氨酸和可溶性蛋白含量的升高是降低和缓冲植物重金属逆境胁迫产生的伤害，抗氧化酶系统的不同变化对缺铁和Cd胁迫所产生的伤害进行修复。 盆栽实验表明，缺铁处理的生物量低于相应的加铁处理，富集的Cd高于相应的加铁处理，转移系数与富集系数高于加铁处理。缺铁处理铁的地上部和根部含量显著低于相应的加铁处理。玉米与小麦加铁与缺铁的植物铁载体的分泌率随着Cd浓度升高呈现降低的趋势，并且缺铁处理植物铁载体的分泌率高于加铁处理。

Multi-mode Vortex-induced Vibration of Slender Cable Experiencing Shear Flow

The dynamic characteristics of slender cable often present serried modes with low frequencies due to large structure flexibility resulted from high aspect ratio (ratio of length to diameter of cable), while the flow velocity distributes non-uniformly along the cable span actually in practical engineering. Therefore, the prediction of the vertex-induce vibration of slender cable suffered from multi-mode and high-mode motions becomes a challenging problem. In this paper a prediction approach based on modal energy is developed to deal with multi-mode lock-in. Then it is applied to the modified wake-oscillator model to predict the VIV displacement and stress responses of cable in non-uniform flow field. At last, illustrative examples are given of which the VIV response of flexible cable in nonlinear shear flow field is analyzed. The effects of flow velocity on VIV are explored. Our results show that both displacement and stress responses become larger as the flow velocity increasing; especially higher stress response companied with higher frequency vibration should be paid enough attention in practical design of SFT because of its remarkable influence on structure fatigue life.

青杨(Populus cathayana Rehd)雌雄植株对锈病和干旱胁迫的生理响应及差异蛋白质组比较

雌雄异株植物对环境的不同响应一直是一个有趣而新颖的研究领域，由于雌雄个体不同的繁殖成本及不同的生存策略，使得雌雄植株在生长、存活、生殖格局、空间分布、资源配置等方面已经表现出明显的不同，在生理和分子水平上也表现出明显的性别间差异。干旱是制约农林业发展的环境因子之一，叶锈病是对杨树危害最严重的病害之一，由于长期进化的结果，不同性别的植物必然对生物和非生物胁迫有着不同的响应。本文以雌雄异株的青杨为模式植物，研究雌雄间在生理、生化、亚细胞结构和蛋白质水平上对生物和非生物胁迫的差异响应。主要研究结果如下： （1） 青杨雌雄植株对锈病胁迫的生理生化差异响应 在正常的对照组中，雄株叶片比雌株叶片有着较高的活性氧自由基产生速率、较高的SOD、POD、PPO 和较低的CAT 活性；在锈病感染的早期阶段， SOD、POD、CAT 活性、活性氧自由基产生速率、H2O2 含量、膜脂过氧化程度和细胞膜的电渗率在雌雄株中都增加，而PPO 仅在雄株中增加明显，APX 仅在雌株中增加明显，并且雌株比雄株有着更严重的锈病感染程度、细胞膜的伤害程度和光合系统II 的破坏程度，雌株有更多的净光合速率、气孔导度和叶绿素a 含量的降低，在同工酶变化上，雌雄间对锈病也显示出不同的表达模式。结果显示，雄株比雌株对锈病有着更好的抗性和更有效的ROS 清除系统。 （2） 青杨雌雄植株对干旱胁迫的生理生化及亚细胞结构的差异响应 与较好水分条件相比，干旱下雄株比雌株有着更高的A-Ci 响应参数，如Rubisco 最大羧化速率、光呼吸速率、暗呼吸速率和最大电子传递速率等。干旱显著地增加了膜脂过氧化程度和游离脯氨酸含量，并且雄株比雌株表现出较低的膜脂过氧化程度，较高的总蛋白和游离脯氨酸含量。无论是中度干旱还是极度干旱，除了CAT 外，雄株比雌株表现为较强的抗氧化酶活性，在同工酶谱带上，雌雄间表现出不同的变化模式，并且有些条带是干旱影响应的，而有些条带是性别特异性的，这些性别特异性条带能够作为鉴定性别快速而准确的标记。干旱显著地影响了线粒体、叶绿体和细胞壁的结构，尤其在中度干旱胁迫下，雄株线粒体和叶绿体比雌株呈现出较好的完整性，并且雄株细胞壁要比雌株更厚。因此， 雄株比雌株表现出更强的干旱忍耐性和更高效的抗氧化酶系统。 （3） 青杨雌雄植株对干旱胁迫的蛋白质组差异响应 用双相电泳检测到雌雄间近1000 个蛋白点，通过对比发现对照组雌雄间有54 个差异蛋白点，干旱下雌雄间有108 个差异点，其中102 个被质谱成功鉴定。对照组雌雄间的差异蛋白主要集中在与光合作用相关蛋白、抗氧化酶、胁迫防御蛋白和一些调节基因表达的蛋白；干旱胁迫下雌雄间差异蛋白明显增多，主要有参与信号转导、调节基因表达、蛋白质加工、转录产物的转录翻译后修饰的调节性蛋白蛋白和参与氧化还原平衡、抗胁迫、细胞壁合成、光合作用、能量代谢、氨基酸代谢和脂肪酸代谢等的功能性蛋白。干旱下这些蛋白的表达量在雌雄中有的表现出相同的表达模式，如干旱下雌雄株中Rubisco 激活酶、小热激蛋白等表达都增加，而有的表现出相反的表达模式，如Rubisco 大亚基的降解片段、羰酸酯酶等在雄株中表达量上调而在雌株中却是下调。因此，雌雄间在蛋白质水平上对干旱胁迫响应的差异是显著的，也是复杂的。 It is an interesting and novel topic that dioecious plants possess different responses to environmental stress. As for the different productive cost and different survive strategy, different sexual plants have shown obviously morphological, physiological and molecular differences. Drought is one of the most worldwidely important environmental stress factors that limit plant growth and ecosystem productivity. Rust disease is one of the economically important diseases in many trees. As a result of the long evolutionary process, male and female plants should show different responses to abiotic and biotic stress. In this paper, using a dioeious tree of Populus cathayana Rehd as a model, we study the sexual differences to drought and rust disease stress in physiological, biochemical, sub-cellular and proteomics levels. The main results are follows: (1) The sexual differences in physiology and biochemistry of poplar to rust disease In controls, males showed higher production of superoxide radicals, higher activities of SOD, POD, PPO and lower CAT activity. Under rust disease, the activities of antioxidant, the content of ROS and the degree of cellular member destroyed were increased in both sexes, except for PPO in diseased males and APX in diseased females. However, females showed more seriously disease severity and cellular member and PS II destroyed degrees. Net photosynthesis rate, transpiration rate and chlorophyll a content were decreased more in diseased females than in males. There were also some different changes inantioxidant isozymes under rust disease. The results suggested that male poplar possessed a more effectively antioxidant system and were more resistant to rut disease than females. (2) The sexual differences in physiology and biochemistry of poplar to drought stress Under drought stress, there were higher rates of RuBP-saturated CO2 assimilation, dark respiration, photorespiratory release of oxygen, the max electron transportrate in CO2-saturated and carboxylation efficiency in males than in females. And males showed lower TBARS and higher proline content. Except for CAT, the activities of other antioxidants were higher in males than in females. Meanwhile, there were obviously differences in isozyme changes between teo sexes. Drought stress obviously destroyed the integralities of chloroplasts and mitochondria and the sexual differences in sub-cellular level were obviously under the moderate water stress. Male cell walls were more sensitive to drought stress than did female. The results suggested males were more resistant to drought stress. (3) The sexual differences in proteomics of poplar to drought stress By 2-D and MS analysis, we identified 102 different protein spots between males and females. Under control conditions, the different proteins were mainly in photosynthesis related proteins, antioxidants, stress response proteins and some gene expression related proteins. Under drought stress, the different proteins were focused on (i) regulated proteins such as signaling conduction, kinase, HSP, gene expressional regulation and protein modification, (ii) functional proteins such as photosynthesis, energy metabolism, antioxidant, redox, stress response, lipid metabolism and amino acid metabolism. Some protein showed the same expressional pattern, while some showed contrary expressional pattern. Thus, the results suggested that sexual differences in proteomics were significant and complex.