叶轮式增氧机对鱼池溶氧日变化影响的模拟模型初步研究

针对鲜有鱼池溶氧模型考虑增氧机对鱼池溶氧日变化影响的现实,在传统的描述鱼池水温和溶氧日变化多层模型的基础上,通过分析叶轮式增氧机水跃和液面更新对鱼池多层水体中各能量要素和溶氧变化因子的影响,构建了能反映叶轮式增氧机增氧效果的鱼池水温和溶氧日变化模拟模型.通过实验数据对模型的校参和验证,发现溶氧逐小时模拟值与观测数据的均...     

立式泵站盘车连续摆度测量法及分析处理系统开发

为了解决难以控制盘车角速度从而导致的测量摆度数据无法与角度对应的问题,通过使用电涡流传感器与新型光栅传感器结合的装置,采用变速盘车自适应的连续摆度测量法,研发基于Matlab开发的摆度分析处理系统,准确计算了泵轴固定测点上的摆度数据,并给出了相应的轴线调整方案,相关成果可应用于大型立式泵站盘车及摆度测量中.     

Myo-inositol prevents oxidative damage, inhibits oxygen radical generation and increases antioxidant enzyme activities of juvenile Jian carp (Cyprinus carpio var. Jian)

This study was conducted to evaluate the effects of dietary myo -inositol (MI) on the antioxidant status of juvenile Jian carp ( Cyprinus carpio var. Jian). A total of 1050 Jian carp (22.28±0.07 g) were randomly distributed into seven groups of three replicates each, feeding diets containing graded levels of MI (163.5, 232.7, 384.2, 535.8, 687.3, 838.8 and 990.3 mg kg⁻¹ diet) for 60 days. Results indicated that the malondialdehyde content was the lowest for fish fed diets containing ≥384.2 mg MI kg⁻¹, and the highest for fish fed the MI-unsupplemented basal diet ( P <0.05). The protein carbonyl content was decreased with increasing dietary MI levels up to 535.8 mg kg⁻¹ diet, and no differences were found with a further increase in the MI concentration. The anti-superoxide anion capacity (ASA) and anti-hydroxyl radical capacity (AHR) were increased with increasing MI levels up to 535.8 mg kg⁻¹ diet, and plateaued thereafter. The superoxide dismutase and glutathione- S -transferase activities showed the same tendency with the ASA capacity. Catalase, glutathione peroxidase and glutathione reducase activities were improved with increasing MI levels up to 838.8, 384.2 and 687.3 mg kg⁻¹ diet, respectively, and remained nearly constant thereafter. These results suggested that MI could inhibit oxygen radical generation, increase enzymatic antioxidant capacity and prevent oxidative damage of carp. Dietary MI requirements for ASA and AHR activities of juvenile Jian carp were 567.94 and 517.22 mg MI kg⁻¹ diet respectively.     

植物根尖分生组织传感器的构建及其对尿素传感动力学研究

为探寻植物根尖组织对尿素的传感能力和两者相互作用的动力学规律。以海藻酸钠—淀粉凝胶作固定剂,将玉米、辣椒、花椰菜和黄瓜的根尖分生组织固定到2片核微孔膜之间,制成“三明治”式尿素传感膜,然后将其固定并密封到玻碳电极上,制成植物根尖分生组织传感器。通过电化学工作站和时间—电流曲线法测定尿素与玉米、辣椒、花椰菜和黄瓜的根分生组织传感器互作所产生电化学信号的变化。与对照组相比,4种植物根尖分生组织传感器对不同浓度的尿素均呈现明显的函数关系。根分生组织传感器对不同浓度的尿素传感动力学测定结果表明:玉米、辣椒、花椰菜和黄瓜分别在10^-8~10^-4、10^-16~10^-6、10^-19~10^-10和10^-20~10^-10 mol·L^-1的尿素范围内呈现类似于酶和底物响应的酶促反应特征(联动变构效应)。进一步分析显示:玉米、辣椒、花椰菜、黄瓜和尿素的联动变构常数Ka(类似于酶—底催化动力学的米氏常数Km)分别为:7.197 0×10^-9、4.537 0×10^-16、9.908 5×10^-20和6.462 8×10^-21 mol·L^-1,表明玉米对尿素的传感能力至少比其他3种植物差7个数量级以上。在以尿素为唯一外源氮营养的条件下培养玉米和辣椒,实验结果证明,在低于玉米传感尿素能力下限(1×10^-10 mol·L^-1)时,玉米10~15 d枯黄死亡,而辣椒可以正常生长。证明联动变构常数Ka反映了植物根尖分生组织对尿素的真实传感能力,而且玉米对尿素的传感存在某种程度上的缺陷。     

不同诱导因子对膜脂过氧化与对超微结构影响的关系

为了阐明诱导因子诱导系统获得性抗性机制,研究了百草枯PQ,钛铁试剂Tiron和稻白叶枯菌弱毒株XOO75-1等诱导因子对稻白叶枯病的系统获得抗性、诱导叶活性氧代谢及挑战接种叶超微结构的影响.结果表明,PQ和XOO75-1可诱导系统获得抗性.XOO75-1使处理稻叶SOD和CAT活性降低,使POD活性、O2i产生速率及MDA含量升高;PQ使SOD,CAT,POD活性、O2i产生速率及MDA含量升高;两者均使处理稻叶膜脂IUFA降低,饱和脂肪酸相对含量升高.PQ和XOO75-1使挑战接种叶病斑附近组织结构受保护,比未处理叶的细胞结构损伤小,较接近正常叶,细胞内结构以叶绿体变化最为显著.Tiron处理使PQ和XOO75-1诱导的系统获得抗性减弱,诱导局部的活性氧变化减小以及病斑附近的结构改变更显著.证明O2i在XOO系统获得抗性中起重要作用.     

水稻与基腐病菌互作中的活性氧代谢

对水稻与基腐病菌互作中活性氧及其相关酶系与抗性关系进行了研究。结果表明:超氧阴离子自由基(O2.-)、H2O2、MDA在接种后24 h达到高峰,且抗病品种的含量比感病品种高;SOD在抗感品种接种病菌24 h后活性增加,均达到高峰,然后开始下降,但总趋势为抗病品种低于感病品种;CAT在接种后24 h和96 h,感病品种出现2个高峰,而抗病品种的活性在整个过程中变化不明显。     

Anti-oxidant status in embryonic,post-hatch and larval stages of Asian seabass (<Emphasis Type="Italic">Lates calcarifer</Emphasis>)

The concentrations of anti-oxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (SeGPx), and low molecular weight free-radical scavengers such as reduced glutathione (GSH) and ascorbic acid (vitamin C) were evaluated during the period from gastrulation (GS) to 25 days post-hatch (dph) in the larvae of Asian Seabass, Lates calcarifer. Oxidative damage due to lipid peroxidation (LPO) was also assessed, by evaluation of the formation of malondialdehyde (MDA). All the three anti-oxidant enzymes, SOD, CAT and GPx, showed high activities during gastrulation, suggesting an increased metabolic rate during the period of embryonic development. Though the SOD activity apparently decreased progressively during 3–20 dph of larval development, the difference was not significant. CAT showed high activity during gastrulation and remained constant up to 3 dph, suggesting an increased need to metabolise hydrogen peroxide (H₂O₂) and organic peroxides. In contrast, SeGPx activity increased progressively from 5 dph to 25 dph during larval development, indicating an increased need to detoxify lipid peroxides. This is evident from the observation of increased lipid peroxidation from 10 dph to 25 dph during larval development. GSH levels were low at gastrulation, indicating increased metabolic rate and formation of lipid radicals during this period, corresponding to the decrease in the level of ascorbic acid, which is consumed for regeneration of GSH.     

Oxygen consumption of the ascidian Styela clava in relation to body mass,temperature and salinity

The metabolic physiological response to body mass, temperature (12–28 °C) and salinity (20–36 g L^?1) was examined in this paper. Oxygen consumption rate, which is dependent on environmental conditions, was exponentially related to body mass and varied from 0.045 to 1.11 mg h^?1 g^?1. Oxygen consumption rate increased as salinity increased from 20 to 36 g L^?1, and increased with increasing temperature. The effect of temperature gradient between experimental treatments on oxygen consumption rate was evaluated by calculating Q₁₀ (the Arrehenius relationship for increase with temperature). The Q₁₀ value within the temperature range from 12 to 16 °C was much higher than the value within the temperature range from 16 to 20 °C, 20 to 24 °C and 24 to 28 °C, indicating a reduced temperature dependence of ascidian metabolism at a high temperature.     

Sensing of tomato plant response to hypoxia in the root environment

A severe drawback in hydroponic production systems and irrigated field cultivation arises due to the risk of hypoxia, provoked by water logging in the root environment. The effects of hypoxia become temporarily visible when plants are irreversibly damaged. For this reason, non-invasive methods are required for detecting hypoxia in good time. In five experiments, tomato plants at two stages of development were grown in containers in aerated nutrient solution. Aeration was interrupted to trigger hypoxic conditions in the root environment. Whereas young plants were able to adapt to hypoxia in the root environment and survived, mature plants wilted two days after aeration interruption and died rapidly. A decrease in leaf photosynthesis, leaf transpiration rates and efficiency of the photosystem II was observed in older plants, while leaf diffuse reflectance changed slowly. On the other hand, if young plants were able to adapt to hypoxia in the root environment and survived, no clear reduction of leaf photosynthesis and the efficiency of the photosystem II arose, although the dry matter growth was decreased by 50%. Changes in leaf colour and reflectance spectra occurred. The latter indicated changes in the profile of the carotenoids. The ratio of intensities at 550 and 455 nm in particular provided a sensitive and diagnostic parameter for hypoxia in the root zone of adapted plants which, nevertheless, displayed severe growth limitation.     

Effect of silicon on antioxidant and stomatal response of two grapevine (Vitis vinifera L.) rootstocks grown in boron toxic,saline and boron toxic-saline soil

We investigated individual and combined effects of B toxicity and salinity in the presence or absence of silicon on the shoot growth, concentrations of sodium (Na), chloride (Cl), boron (B) and silicon (Si), and stomatal resistance (SR), lipid peroxidation (MDA), proline accumulation, H₂O₂ accumulation and the activities of major antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT and ascorbate peroxidase, APX) activity grapevine rootstocks of 41B (V. Vinifera × V. Berlandieri) and 1103P (V. Berlandieri × V. Rupestris). Applied Si counteracted the deleterious effects of salinity and boron toxicity on shoot growth by lowering the accumulation of Na in 1103P, and B and Cl in the both rootstocks. Stomatal resistance, MDA, and the concentrations of H₂O₂ and proline were higher in the plants grown in conditions of B toxicity, salinity and their combination while applied Si lowered these parameters. Lowering SOD and CAT but increasing APX, Si treatment significantly affected the enzyme activities of both rootstocks. Based on the present work, it can be concluded that Si alleviates the adverse effects of salinity, B toxicity and combined salinity-B toxicity on grapevine rootstocks by preventing both oxidative membrane damage and translocation of Na and B from root to shoots and/or soil to plant, and also lowering the phytotoxic effects of Na and B within plant tissues. When considering the antioxidative response and membrane systems, it was concluded that the rootstock 1103P was responsive to Si under stress conditions. To our knowledge, this is the first report that Si improves the combined salt and B tolerance of grapevine grown under saline, B toxic, and B toxic and saline conditions which describes membrane related parameters and antioxidant responses.