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1.
百草枯和H2O2预处理提高盐泽螺旋藻对铅的耐受性   总被引:9,自引:1,他引:8  
用10μmol.L^-1的百草枯(Paraquat)和2mmol.L^-1的H2O2对盐泽螺旋藻(Spirulina subsalsa)作预处理,以诱导提高藻细胞内超氧物歧化酶(SOD),过氧化氢酶(CAT)和过氧化物酶(POD)的活性,随后用40mg.L^-1的Pb^2+进行肋迫试验,实验结果表明,预处理组的藻细胞生长量和光合速率的下降幅度明显较未预处理组小;预处理组的SOD、CAT活性虽有衰减  相似文献   

2.
谢家树  王亚秀 《地震》1994,(1):31-35
本文定义地震的时空距DST格时空转换系数C为:D^2ST=d^2+C^2(△t)^2,d为序列中连续发生的两次地震的空间距,△t为时间间隔。采用60年代来发生在我国5级以上有详细目录的地震序列23个,分别计算了主震后1天,2-3天,4-7天内C的值C1,C3,C7,计算中取DST为相应时间段内地震空间距的最大值。结果表明:(1)若C1>C3>C7,则无强余震发生;(2)若C1≌C3,或C1<C3<  相似文献   

3.
胡东生 《湖泊科学》1995,7(4):327-333
对柴达木盆地察尔汗盐湖区外围沙下盐湖的卤水及沉积进行了综合研究。沙下盐湖卤水化学组成与地表径流和开放性盐湖卤水之间存在明显的差异性,具有高Na^++Cl^-、低Mg^2++Ca^2++SO4^2-、贫K^++CO3^2-+HCO3^-等特征。沙下盐湖析盐层位含有新生矿物并夹带碎屑矿物,其盐类矿物组合为:石盐+羟氯镁铝石+光卤石。25℃等温蒸发相图表明,其卤水演化方向往光卤石析出区迁移,在穿越上覆盖  相似文献   

4.
首次提出用石笋中稳定同位素记录重建由降雨量和降水气团同位素组成所反映的古气候历史,从而为研究分辨率古季风气候信息开辟了新的途径,利用Hendy准则,洞穴温度,研究区水系的δ^18OH2O值以及温度公式,证实了同位素分析结果的可靠性CaCO3-H2O之间存在同位素平衡分馏,对采自石花洞的石笋样品进行了分辨率约在25a的δ^18O和δ^13C的分析测量,从而得到3000a以来,北京地区古气候和古环境的  相似文献   

5.
红河断裂北段土壤中断层气含量变化特征   总被引:1,自引:0,他引:1       下载免费PDF全文
介绍了作者在滇西地震预报实验场区进行的土壤中断层气研究结果.沿红河断裂带断层气组分H2,CO2,Hg和Rn含量很高.沿该断裂洱源测线断层气H2,CO2和Rn含量最低,向南H2,CO2含量逐渐升高,其中以定西岭测线的H2,CO2含量最高.表明在该段断裂活动强烈,而洱源一带断裂活动较弱.  相似文献   

6.
野外监测土壤CO2释放结果表明,土壤CO2释放量晴天高于雨天,洼地,垭口土壤CO2释放量高于坡地土壤CO2释放量,试验场土壤CO2年释放量在1057.8t(1.763kgm^-2)与552.6t(0.921kgm^-2)之间,估算值为810.0t(1.35kgm^-2)。野外溶蚀试验结果表明,试验场岩土作用过程年吸收CO2量为13.08t,岩溶系统年吸收CO2量为61.73t。土壤温室气体(CO2  相似文献   

7.
好氧和厌氧条件对霞浦湖沉积物-水界面氮磷交换的影响   总被引:55,自引:4,他引:55  
在实验室控制条件下,研究了日本霞浦湾和湖心区底泥中形态氮磷,在好氧和厌氧条件下水土界面交换量变化及差异,结果表明;好氧条件下,NO^-3-N,NO^-2-N,NH^+4,-N,和PO^3-4-P均有释放作用产生,量值多数较小,DTN和DTP则净释放作用接近零;厌氧条件下,NO^-3-N和NO^-2-N呈负释放状态,NH^+4-N和PO^3-4-P的释放速率是好氧条件下的2-8倍。  相似文献   

8.
太湖北部梅梁湾水域水质因子聚类   总被引:7,自引:5,他引:7  
刘元波  高锡芸 《湖泊科学》1997,9(3):255-260
计算了沿梁溪河河口到太湖湖心断面上10个监测点17个水质因子93组数据的Pearson相关系数和Kendall秩相关系数,进而运用最小距离法进行了因子聚类,正态分布检验和聚类结果表明,采用Kendall秩相关进行了聚类为宜,结果将诸因子聚为五大类:TDN,TN,CON,NO2-N,NH4-N,OH和CODMn归为一类,TDP,TP,PO^3+4和pH值归为一类;SS和SD归为一类,反映了该水域环境  相似文献   

9.
震源对地震动空间相关性影响的定量研究   总被引:5,自引:2,他引:3  
在震尖为线性破裂断层模型的假定下,本文根据震源理论和波谱随空间坐标的展开式,定量分析了震源对地震动空间相关性的影响,得到了场地上相距为d的a、b两点地震动的Fourier谱的关系式为Ab(f)=Aa(f)exp(a1δr0+a2δθ)。其中a1,a2为与震源参数、介质我和场地位置相关并随频率变化的两个复数,δr0与δθ为与台丫相对位置有关的参数。本文给出了计算a1和a2的理论公式,并对a1和a2的  相似文献   

10.
女山湖现代沉积速率和环境解释   总被引:6,自引:1,他引:6  
为探讨本世纪以来女山湖生态环境的演化历史,以^137Cs和^210Cb放射性同位素为测试手段,分析该湖近期沉积物中^137Cs和^210Pb的含量分布,并根据其沉降特征和衰减规律,对沉积物做了年代定位,分段推导出平均沉积速率,建立柱状沉积年代序列。在此基础上,利用沉积记录,对沉积速率的变化进行环境解释,探讨了本世纪以来湖泊环境的演化过程。结果表明,1929 ̄1938年沉积速率达4.8mm/a,是淮  相似文献   

11.
利用人工配制的生活污水先进行单胞藻(斜生栅落Scenedesmus obliquus Turp)的培养,再接种田螺(Cipangopaludina sp.)和短钝蚤(Daphnia obtusa Kurz)对栅藻密度的经时变化,短钝蚤种群增长及水体中氮,磷,碳在培养过程中的变化作了与分析。  相似文献   

12.
对于不同生长期、不同湿度条件下芦苇(Phragmites australis)茎、叶中多种类型植硅体含量变化的探讨,能够为植硅体形成机理研究和探讨植硅体对气候变化的响应提供理论依据.选取长春市南湖为实验样点,于5—10月在3种不同生境(旱生、季节性水生和水生生境)采集芦苇样品,并分别统计芦苇茎、叶植硅体形态和数量.实验结果显示:首先,茎、叶植硅体组合特征存在明显差异,茎中帽型及个体较大的尖型等植硅体多于叶中,而叶中硅化气孔含量明显高于茎中.其次,随着植株的生长,芦苇茎中硅化气孔含量先增加后减少,鞍型植硅体含量变化较小而帽型植硅体含量先减少后增加,棒型植硅体含量逐渐增加、尖型植硅体含量先增加后减少;芦苇叶中硅化气孔含量持续增加,鞍型、帽型等短细胞植硅体含量下降,尖型、扇型等个体较大的植硅体含量逐渐增加.最后,不同植硅体类型的含量在3种生境中的变化情况较为复杂,茎中植硅体的数量变化没有明显规律,而芦苇叶中硅化气孔含量由旱生生境向水生生境逐渐增加,可见叶中硅化气孔含量的增加可以指示相对湿润的生境条件.总之,芦苇茎、叶内不同类型植硅体的数量对植株生长及不同湿度环境有不同程度的响应,对芦苇植硅体的研究也有助于理解湿生植物植硅体与环境因子的关系,进而为探讨植硅体对古环境、古气候的响应提供理论基础.  相似文献   

13.
外源ASA对菹草(Potamogeton crispus)抗Cd2+毒害的实验分析   总被引:2,自引:0,他引:2       下载免费PDF全文
实验以高等水生沉水植物菹草为材料,研究在不同浓度Cd^2 毒害条件下外施乙酰水杨酸(ASA)对菹草叶中叶绿素含量、可容性蛋白含量、O2^v产生速率、保护酶——超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的影响结果表明,施用ASA可以显著提高叶绿素和可溶性蛋白的含量,增强保护酶的活性,降低O2^v产生速率、从而减轻了重金属Cd^2 胁迫对植物体造成的伤害.  相似文献   

14.
Cd2+和Cr6+对慈姑(Sagittaria sagittifolia L.)的毒害效应   总被引:3,自引:0,他引:3  
以水生经济植物慈姑(Sagittaria sagiuifolia L.)为实验材料,通过模拟水体Cd^2+和Cr^6+污染环境,研究了两种单一离子处理对慈姑的毒害影响.结果表明:随着水体Cd^2+、Cr^6+浓度增大,慈姑叶绿素含量与根细胞质膜透性先升高后降低;Cd^2+浓度增大,根和叶的POD活性,叶的SOD活性、丙二醛(MDA)含量及根的超氧阴离子(O2^-)产生速率均是先升后降;根和叶的CAT活性、根的SOD活性、MDA含量和叶的O2^+产生速率则逐渐升高;而Cr^6+处理时,MDA含量、根的SOD、CAT、POD活性均随浓度增大而升高,O2^-产生速率和叶的SOD、CAT、POD活性则升高后降低;Cd^2+和Cr^6+污染都对慈姑产生毒害,其毒害的效应既有相似性又有差异,同浓度条件下根的受害程度比叶严重.  相似文献   

15.
铅污染对钝顶螺旋藻生长及某些生理性状的影响   总被引:13,自引:1,他引:12       下载免费PDF全文
通过在Zarrouk培养基中加入不同浓度的Pb^2+,研究水环境污染对钝顶螺旋藻生长,藻蓝蛋白和光合作用,膜脂过氧化反应及以超氧化物歧化酶为代表的自由基清除系统的影响。发现当Pb^2+浓度高于20mg.L^-1时,钝顶螺旋藻生长受抑制,藻细胞随着浓度的和升高和时间的延长而黄化死亡。  相似文献   

16.
A structural mode was used to characterize vegetation composition at the plant leaf level and a flourishing-withering ratio was developed. The spectral responses of vegetation with different flourishing-withering ratios were analyzed, the change rates of the chlorophyll and moisture content indices of vegetation with different flourishing-withering ratios were compared, and correlations between the chlorophyll and moisture content indices were analyzed. The results reveal that leaves with an intermediate flourishing-withering ratio can increase the absorption signatures of vegetation and that band ranges of 570–700 nm and 1300–1540 nm can play a role in indicating changes in the flourishing-withering ratios of vegetation; NPQI, NPCI, R695/R420, R695/R760, R750/R700, the peak-value area of red selvedge, the red selvedge amplitude, the ratio between the red selvedge amplitude and the minimum amplitude, and the NDVI of vegetation change regularly with the change in flourishing-withering ratios, and these nine vegetation indices are highly related to the chlorophyll content. Vegetation indexes of NDWI and PRI are very sensitive to the flourishing-withering change in vegetation and are closely related to the moisture content, and the correlation coefficient is higher than 0.9. The derivative of the spectra is more effective in describing changes in the structural mode of vegetation with different flourishing-withering ratios, especially at band ranges of 552–628 nm and 630–686 nm, and it is more sensitive to the mixed flourishing-withering ratios of leaves rather than to the vegetation indices. The red selvedge position in the spectrum is highly related to the chlorophyll content and is not sensitive to changes in the structural mode of mixed flourishing-withering leaves. The red selvedge parameters are sensitive to changes in the flourishing-withering ratio at the peak-value area of the red selvedge amplitude and the ratio between the red selvedge amplitude and the minimum amplitude. The effect of a sand background on the spectrum of withering leaves is higher than that of flourishing leaves; the effect of a sand background increases with increasing proportions of withering leaves, the superposition effect of the sand background on mixed flourishing-withering leaves is about 7% at visible light bands of 400–700 nm and 1300–1540 nm, and is over 10% at the near infrared band range of 700–1300 nm.  相似文献   

17.
莼菜(Brasenia schreberi)冬芽对Cr6+污染的抗性反应   总被引:3,自引:0,他引:3  
研究了Cr^6 污染对Shun菜冬芽外部形态及过氧化物酶、硝酸还原酶活性,叶绿素、O^-2、MDA的含量等生理指标的影响,结果显示:Cr^6 对Shun菜毒害机制在于 制酶活性和损害细胞膜系统,在培养第三天时叶绿素的含量随着Cr^6 浓度的增加而降低;过化物酶的活性在10mg/L中最高;硝酸还原酶活性除在5mg/L中的略微升高外,在10-40mg/L之间随着Cr^6 培养浓度的升高而降低;O^-2的含量在5mg/L中的最高,在10mg/L中略高于对照,在随后培养中承学度的升高而降低,MDA的含量变化趋势和O^-2相似。  相似文献   

18.
淹水环境中芦苇幼苗对两种底质的生理响应及其恢复状况   总被引:1,自引:0,他引:1  
探讨湿地植物对淹水的响应及其恢复生长状况对于湖泊湿地的修复具有重要意义.以芦苇(Phragmites commu-nis)为对象,研究其在湖泊沉积物(LS)和农田土壤(AS)两种底质上完全淹水一个月内每隔5 d其叶片相对叶绿素含量(rChlc)、丙二醛含量(MDA)和叶绿素荧光特性的变化,并分别于淹水后的10、20和30 d对其恢复状况进行研究.结果表明:缓苗期间生长于LS上芦苇的rChlc和叶绿素荧光特性均高于生长于AS上的,淹水后rChlc逐渐下降,20 d后下降趋势更加明显,30 d时LS和AS上芦苇叶片的rChlc分别下降了40.82%和39.49%,MDA则逐渐升高,且生长于AS上的要高于LS上的;叶绿素荧光参数Fv/Fm和Y也均逐渐下降,且总体上与rChlc的变化呈显著正相关;LS上芦苇叶片的快速光响应曲线(RLCs)在淹水后缓慢下降,至25 d后下降明显,而AS上的则在15 d后即显著下降.淹水胁迫解除后,两种底质上芦苇的rChlc和叶绿素荧光特性均逐渐升高,总体上AS上芦苇的增幅大于LS上的,但LS上的各指标仍大于AS上的,而MDA逐渐下降,同样AS上的降幅要大于LS上的;随着淹水时间的延长,芦苇恢复到正常生长状态的时间有所增加,淹水30 d的芦苇叶片凋落并萌发出新叶和新的植株,同时LS上芦苇的恢复时间要短于AS上的.可见,淹水抑制了幼苗期芦苇的生长,且随着时间的延长其抑制程度逐渐加重;淹水时间短时芦苇能较快地恢复生长,淹水时间长时则需要长出新叶和萌发出新的植株来适应生长,同时营养状况良好的底质在增加芦苇耐淹性及加快其淹水后的恢复生长方面具有一定的积极意义.  相似文献   

19.
Temporal and spatial distributions of dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) were determined in the East China Sea and the Yellow Sea during June-July, 2006 and January-February, 2007. The concentrations of DMS and total DMSP in surface water in the study area were 5.64 (1.79-12.24) and 28.25 (13.98-44.93) nmol L−1 in summer, and were 1.79 (1.02-3.51) and 11.01 (6.90-17.98) nmol L−1 in winter, respectively. The distributions of DMS and DMSP in the study area were obviously influenced by the Yangtze River effluent and the Kuroshio water. Even under highly variable hydrographic conditions, a significant relationship was observed between DMS and chlorophyll a concentrations in summer as well as in winter, suggesting that phytoplankton biomass might play an important role in controlling DMS distribution in the study area. The summer ratios of DMS/chlorophyll a and DMSP/chlorophyll a were approximately twofold higher than winter values, corresponding with the temporal variation in phytoplankton community structure between summer and winter. The sea-to-air fluxes of DMS were estimated to be 5.32 and 11.92 μmol m−2 d−1 using the equations of Liss and Merlivat (1986) and Wanninkhof (1992), respectively.  相似文献   

20.
There is major uncertainty in the responses of litter decomposition to the inundation regimes in field studies, mainly because of the difficulties in identification of the individual effect of duration and frequency using field studies alone. The interactive role of inundation regime and litter quality also remains unclear. The responses of mass loss to simulated inundation regime (duration and frequency) and litter quality were investigated in leaves of Carex brevicuspis and leaves and stems of Miscanthus sacchariflorus from Dongting Lake, China. Three litter types differing in litter quality were incubated under seven different inundations over 360 days (three single inundations of 90, 180, and 360 days; three repeated 180-day inundations of 2, 3, and 6 times; and no inundations) in a pond near Dongting Lake. Initial N and P contents were highest in C. brevicuspis leaves, intermediate in M. sacchariflorus leaves, and lowest in M. sacchariflorus stems, whereas the organic C, cellulose, and lignin contents were ranked in the opposite order among the three litter types. Decomposition rate was highest in M. sacchariflorus leaves (0.00222–0.00900 day−1), intermediate in C. brevicuspis leaves (0.00135–0.00500 day−1), and lowest in M. sacchariflorus stems (0.00080–0.00100 day−1). The decomposition rate of both C. brevicuspis and M. sacchariflorus leaves increased with increasing inundation duration or decreasing frequency. However, both duration and frequency of inundation had no effect on decomposition of M. sacchariflorus stems. At the end of the incubation, N mineralization was complete in leaf litters with increasing rates with increasing inundation duration or decreasing inundation frequency, but accumulation was found in M. sacchariflorus stems. Organic C decayed quickly in both leaf litters compared with the stem litter. These data indicate that inundation regime has no effect on the decomposition of refractory stem litter while prolonged and stable inundation stimulates the degradation of labile leaf litter.  相似文献   

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