CO_2浓度倍增对城市银杏(Ginkgobiloba)叶片膜脂过氧化与抗氧化酶活性的影响

以生长在沈阳市区内的银杏为试材,使用开顶箱模拟法对倍增CO2浓度(700μmolmol-1)和正常空气CO2浓度(≈350μmolmol-1)条件下银杏生长参数,超氧阴离子自由基(O2-.)产生速率,丙二醛(MDA)含量,抗坏血酸(ASA)含量,超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)及谷胱甘肽还原酶(GR)活性动态变化进行分析,探讨高浓度CO2对银杏膜脂过氧化与抗氧化酶活性的影响。结果表明,在短期(60d)内CO2浓度倍增使银杏细胞内O2-.产生速率与H2O2含量减少,而ASA含量与SOD、APX、GR活性升高。与对照相比,大多数测定显示出显著差别。但较长期(70d以上)CO2浓度倍增处理则使试验结果发生逆转,活性氧O2-.产生速率略有升高,SOD、APX、GR活性略有下降,ASA含量仍略高于对照(但与对照相比差异并不显著),长期CO2浓度倍增处理可能使试验结果发生逆转。

CO_2浓度倍增对城市油松抗氧化酶活性的影响

利用OTC(开顶箱)法模拟未来CO2浓度,于CO2倍增浓度(700μmol·mol-1)和正常空气CO2浓度(≈350μmol·mol-1)条件下,测定了沈阳市区油松(Pinustabulaeformis)针叶超氧自由基(O2.-)产生速率、过氧化氢(H2O2)含量、超氧化物歧化酶(SOD)与抗坏血酸-谷胱甘肽循环(ASA-GSHcycle)主要酶活性动态变化,探讨高浓度CO2对油松抗氧化酶活性的影响。结果表明:在短期(60d)内CO2浓度倍增使油松超氧自由基(O2.-)产生速率与过氧化氢(H2O2)含量减少,而SOD、抗坏血酸过氧化物酶(APX)、单脱氢抗坏血酸还原酶(MDAR)、脱氢抗坏血酸还原酶(DHAR)、谷胱甘肽还原酶(GR)活性升高;植株抗氧化能力增强,对活性氧清除能力提高;但长期(70d以上)CO2浓度倍增处理则可能使试验结果发生逆转。

CO_2浓度升高对两种沈阳城市森林树种光合特性的影响

利用开顶式气室,研究了CO2浓度升高条件下城市森林主要树种油松(Pinus tabulaefomis)和银杏(Ginkgo biloba)主要光合特性的变化。结果表明,整个生长季,CO2浓度升高(700μmol.mol-1)条件下2树种叶片的净光合速率、可溶性糖、淀粉和可溶性蛋白含量均接近或高于相应对照(自然CO2浓度)值,但不同树种增加的幅度不同;而2树种的叶绿素含量和Chla/Chlb值对CO2浓度升高反应不一,表现为CO2浓度升高条件下油松的叶绿素含量较对照值高,Chla/Chlb值降低,银杏的叶绿素含量为前期升高,后期降低,Chla/Chlb值变化与之正好相反,说明城市森林组成树种对CO2浓度升高的响应具有复杂性。CO2浓度升高条件下,两树种均未发生光合适应现象。

CO_2质量浓度对沈阳市银杏生长及光合固碳能力的影响

以生长在沈阳市区内的银杏为试材,使用开顶箱模拟法对倍增CO2质量浓度(700μmol．mol-1)和正常空气CO2质量浓度(≈350μmol．mol-1)条件下,银杏生长参数、叶面积指数、不同天气中净光合速率日变化进行了初步研究,探讨了高质量浓度CO2对单株银杏光合固碳能力的影响。结果表明:CO2质量浓度增高可以显著提高银杏枝条的生长量和银杏的叶面积指数。经高质量浓度CO2处理后,银杏不同天气下光合速率日变化趋势与对照一致,即晴天为双峰曲线,多云天气为单峰曲线,但净光合速率显著高于对照(P<0．001)。由于净光合速率和叶面积指数升高,高质量浓度CO2也显著提高了单株银杏的固碳释氧能力(P<0．01),晴天比对照提高了119．5％,阴天提高了175．4％。

O_3与CO_2浓度倍增对油松针叶抗氧化酶活性的影响

以4年生的油松幼苗为试材,采用开顶箱内气体熏蒸实验,对经高浓度O3(80nmol.mol-1)和CO2(700μmol.mol-1)单一及复合处理3年后,油松当年生针叶内丙二醛(MDA)含量、活性氧自由基和抗氧化酶等逆境生理指标进行了分析。结果表明:超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)和脱氢抗坏血酸还原酶(DHAR)活性经O3处理后显著升高,分别比对照上升了43.1%、18.9%、283.5%和142.6%,而CO2和复合处理仅对APX和CAT活性有明显的诱导作用,但均低于O3处理;O3处理导致MDA含量上升51.8%,而外加CO2则能有效逆转这一趋势;超氧阴离子(O2.-)产生速率和H2O2含量在所有处理组合间均无显著差异。上述结果说明,O3能有效地激活油松当年生针叶内的抗氧化酶系统,而CO2能缓解O3所带来的不利影响,但并非通过提高抗氧化酶活性这一途径。

OTC-Ⅰ型开顶式气室优化设计与性能分析

为了模拟CO2、O3质量浓度升高的环境条件,OTC-Ⅰ型优化开顶式气室设计实现计算机自动控制气室内的气体质量浓度,其它环境条件接近自然状态,气室内空间适合木本植物生长。对气室性能试验分析结果表明,高质量浓度CO2处理(700μmol/mol)的变异量≤4%,高质量浓度O3处理(80mmol/mol)的变异量≤9%,说明处理气室内CO2与O3质量浓度比较稳定,各重复气室之间控制气体质量浓度无显著差异。本套系统可用于植物对气候变化的响应研究,所得数据相对可靠,是模拟气体环境的较好装置,适用于长期的监测研究。

SBR法处理高盐度海产品加工废水

采用SBR工艺对高盐度海产品加工废水进行了试验研究,结果表明,海产品加工废水中氯离子浓度不超过10000mg/L的情况下,采用具有一定耐盐度冲击负荷能力的SBR工艺是可行的;当进水中COD_(Cr)浓度为700～1000mg/L、NH4+-N浓度为80～120mg/L、[Cl-]≤8000mg/L的情况下,出水COD_(Cr)、NH3-N去除率分别为77.9%～81.2%、69.5%～76.6%,当进水中氯离子浓度继续增加,系统受盐度的影响加剧,处理效果变差。

不同二氧化碳浓度条件下红松和长白赤松幼苗根际土壤微生物数量研究

以连续5年不同CO2浓度(开顶箱700μmol·mol-1、500μmol·mol-1、对照箱和裸地)处理的长白赤松和红松幼苗为研究对象,在2003年7～9月分别对幼苗根际土壤细菌、真菌、放线菌数量进行比较研究.结果表明,高浓度CO2处理对长白赤松幼苗根际土壤细菌数量起显著的(P≤0.001)促进作用,对根际真菌和放线菌数量的促进作用却不明显;对红松来说,除8月份700μmol·mol-1CO2处理和7月份500μmol·mol-1CO2处理之外,在各月份中受高浓度CO2处理的根际土壤细菌数量均较对照箱和裸地显著增多(P≤0.001),而根际土壤真菌数量变化除9月份(P≤0.001)外均不明显,放线菌数量受高浓度CO2的影响亦不明显.

长白赤松和红松土壤微生物活性对高浓度CO_2的响应(英文)

研究了2003 年夏季长白赤松和红松土壤微生物活性对高浓度CO2的响应规律。结果表明,长白赤松和红松土壤细菌数量受高浓度CO2影响显著(p < 0.05)减少;与对照箱(350 μmol ·mol-1 CO2)和裸地(350 μmol ·mol-1 CO2)相比,红松土壤淀粉酶和转化酶活性降低,而长白赤松土壤淀粉酶和转化酶活性却表现为增加;同时发现受700 μmol ·mol-1 CO2处理的红松和长白赤松土壤微生物生物量碳均表现为显著降低。DGGE 结果表明:受高浓度CO2 的影响,长白赤松和红松土壤细菌群落结构发生了明显的变化。研究结果表明土壤微生物对高浓度CO2的响应规律与所研究的的树种有关。图2 表2 参29。

长白山北坡不同海拔植物群落物种丰富度估计(英文)

应用梯度格局法在长白山北坡海拔700-2600 m 之间,海拔每上升100 m设置一块样地,共20块样地。以具体的样地观测数据为基础,应用刀切法和自助法等非参数估计法对各海拔群落的物种丰富度进行了估计,结果表明,用自助法所得到的物种估计数,与客观实际更为接近。同时,根据各海拔群落观测物种数与估计物种数的差异,进一步验证了最小取样面积的合理性。表4参12。

长白山北坡植物群落间物种共有度的海拔梯度变化(英文)

应用梯度格局法在长白山北坡海拔700-2600 m之间每100 m设置一样地，共计20块样地，应用Jaccard指数，对植物群落间物种共有度的海拔梯度变化进行了分析。不同海拔群落间的共有度，无论以哪一层次的植物种来表达，基本都以与其最相邻海拔的群落之间为最高。相邻海拔群落的不同层次物种间的共有度变化存在相似性和相异性；但如相邻海拔的两个群落属于不同植被类型，其共有度则较低。群落间物种共有度的峰值与谷点反映了植被的海拔梯度格局，且灌木种的物种更替在这些地段具有非常明显的规律。在同一海拔差群落间的共有度数值都非常接近，并均随着海拔差的增加呈明显的下降趋势，表明群落各层次物种的构成有很大的相关性。

Ultrafast dynamics of dye molecules in solution as a function of temperature

Femtosecond time-resolved studies using fluorescence depletion spectroscopy were performed on Rhodamine 700 in acetone solution and on Oxazine 750 in acetone and formamide solutions at different temperatures. The experimental curves that include both fast and slow processes have been fitted using a biexponential function. Time constants of the fast process, which corresponds to the intramolecular vibrational redistribution (IVR) of solute molecules, range from 300 to 420 fs and increase linearly as the temperature of the environment decreases. The difference of the average vibrational energy of solute molecules in the ground state at different temperatures is a possible reason that induces this IVR time-constant temperature dependence. However, the time constants of the slow process, which corresponds to the energy transfer from vibrational hot solute molecules to the surroundings occurred on a time scale of 1-50 ps, changed dramatically at lower temperature, nonlinearly increasing with the decrease of temperature. Because of the C-H...O hydrogen-bond between acetone molecules, it is more reasonable that acetone molecules start to be associated, which can influence the energy transfer between dye molecules and acetone molecules efficiently, even at temperatures far over the freezing point.

Ultrafast vibrational and thermal relaxation of dye molecules in solutions

Intra- and intermolecular relaxations of dye molecules are studied after the excitation to the high-lying excited states by a femtosecond laser pulse, using femtosecond time-resolved stimulated emission pumping fluorescence depletion spectroscopy (FS TR SEP FD). The biexponential decays indicate a rapid intramolecular vibrational redistribution (IVR) depopulation followed by a slower process, which was contributed by the energy transfer to the solvents and the solvation of the excited solutes. The time constants of IVR in both oxazine 750 and rhodamine 700 are at the 290-360 fs range, which are insensitive to the characters of solvents. The solvation of the excited solutes and the cooling of the hot solute molecules by collisional energy transfer to the surrounding takes place in the several picoseconds that strongly depend on the properties of solvents. The difference of Lewis basicity and states density of solvents is a possible reason to explain this solvent dependence. The more basic the solvent is, which means the more interaction between the solute and the neighboring solvent shell, the more rapid the intermolecular vibrational excess energy transfer from the solute to the surroundings and the solvation of the solutes are. The higher the states density of the solvent is, the more favorable the energy transfer between the solute and solvent molecules is.

Promotional effect of colloidal alumina on the activity of the In/HZSM-5 catalyst for the selective reduction of NO with methane

Colloidal alumina was used to improve the activity of an In/HZSM-5 catalyst for the selective reduction of NO with CH4 in the excess of oxygen. Compared with In/HZSM-5, the In/HZSM-5/Al2O3 catalyst showed higher activity in a wide range of reaction temperatures. It is visualized that a synergetic effect between In/HZSM-5 and Al2O3 enhances the conversion of NOx. The addition of Al2O3 improved the conversion of NO to NO2 and facilitated the activation of methane. An In/HZSM-5/Al2O3 pre-treated with steam for 15 h at 700 degreesC still showed a high activity for the removal of NOx with methane, while an In/HZSM-5 similarly pre-treated with steam showed a lower activity than the fresh sample. The activity of the In/HZSM-5/Al2O3 catalyst could be restored completely after water vapor was removed from the feed gas. Furthermore, it was found that the In/HZSM-5/Al2O3 remained fairly active under high GHSV and O-2 concentration conditions. It was also interesting to find that an increase in NO content could enhance the conversion of methane, and this illustrates that the existence of NO is beneficial for the activation of methane. (C) 2002 Elsevier Science B.V. All rights reserved.

大气CO_2倍增对长白山不同树种的苗木的影响(英文)

组成长白山阔叶红松林的主要树种红松、云杉、落叶松、大青杨、白桦、椴树、水曲柳和色木的幼树,盆栽于模拟自然光照和人工调节CO2浓度为700祄olmol-1、400祄olmol-1的气室内两个生长季(1998-1999),以生长在400祄olmol-1下的幼树为对照组。研究结果表明:高CO2浓度下生长的红松、云杉、落叶松、大青杨、白桦、椴树、水曲柳和色木的高生长比对照组的幼树提高10%~40%。水分利用效率均有不同程度的提高,但不同树种叶绿素含量和蒸腾速率对高CO2浓度反应不一。长期高CO2浓度环境下生长的阔叶树对大气CO2浓度升高反应较针叶树敏感,供试8个树种对CO2浓度的升高均发生光合驯化现象。图2表2参24。