Effects of clonal integration on growth of invasive clonal plant Alternthera philoxeroides under two kinds of trampling stress were studied.The results are as follows.(1)Severed stolon connection decreased biomass,ramet number,total stolon length and leaf number of apical ramets;however,it obviously increased biomass of basal ramets.(2)Apical ramet trampling stress significantly decreased leaf number and relative chlorophyll content of apical ramets,and basal ramet trampling stress greatly decreased biomass and total stolon length of basal ramets.(3)Under basal ramet trample,stolon connection did not greatly affect ramet number,total stolon length,and leaf number of basal ramets;while it was obviously unfavorable for growth under apical ramet trampling stress.(4)The treatments of trample stress and stolon severing did not affect the performance of whole clonal fragments.
Submerged plants are commonly used in water purification and ecological restoration.The removal rates of four common submerged plants on nitrogen and phosphorus in the water of Houtan Park were analyzed through 30 days laboratory simulation and determination under six different planting densities.The results show that four submerged plants have significantly high removal rates of excessive nitrogen and phosphorus in eutrophic water.Removal efficiency of total nitrogen(TN) by Hydrilla verticillata reaches the highest 65% under planting density of 3 g·L-1,and the highest removal efficiency of total phosphorus(TP)by Potamogeton malaianus reaches 88%.Within the planting density range of 0.5 g·L-1-3 g·L-1,the removal rates of total nitrogen and phosphorus in four submerged plants increased with increasing planting density.
In recent years,bark beetles have seriously affected the local apricot resources in Turpan,Xinjiang.The preference of Scolytus seulensis Murayama and the Scolytus rugulosus Ratzeburg host on Armeniaca spp.to sticky traps with six colors(red,yellow,blue, green,black,and white)was investigated.The results showed that different sticky traps had various attraction effects on bark beetles. The best attraction effect of sticky trap on S.seulensis was found in red,followed by black;while the best attraction effect of sticky trap on S.rugulosus was observed in black,followed by red.Sticky traps with other colors had no obvious attraction effects.The average trapping number of S.seulensis was 11.8±5.0 for sticky trap in black,and average trapping number of S.rugulosus was 16.4±3.0 for sticky trap in red.Moreover,it also could be seen that these two kinds of bark beetle had different emergence peak period,which was in the beginning of June for S.seulensis,and in the middle of July for S.rugulosus.
In the condition of a determined water temperature(20±0.5)℃,the oxygen consumption rate and asphyxiation point of Barbodes schwanenfeldi were determined through the measurement of dissolved oxygen in control and experimental respiration chambers by Winkler's method.Meanwhile,ammonia excretion rate was also determined by Nessler's reagent method.The results indicated that the oxygen consumption rate decreased gradually with increase of body weight and was shown by Y=0.24X-0.09 (R2=0.9028);it also decreased gradually with increase of cultivation density and was shown by Y=-0.0296X+0.3301(R2=0.9291).The ammonia excretion rate decreased gradually with increase of body weight and was shown by Y=-0.0008X+0.2433(R2=0.9817);while it increased with increase of cultivation density and was shown by Y=0.0506X+0.4979(R2=0.9889).The oxygen consumption rate of B. schwanenfeldi was obviously higher during the nighttime(18:00-4:00) as compared to the daytime(6:00-16:00),which showed that B. schwanedfeldi hid in daytime and came out at night.Conversely,the ammonia excretion rate was relatively higher during the daytime. The asphyxiation point of B.schwanenfeldi was 1.2572 mg·L-1,suggesting it had poor tolerance to low dissolve oxygen.
After the investigation and analysis of benthons of Hengqin Island sea area in May 2008,33 species were found, including comate,mollusk,crustacean and Echinodermata.Comate was the dominant species,with a ratio of 42.42% of all the species.Paraprionospio pinnata,Heteromastus filiformis and Magelona crenulifrons were dominated.The total inhabitation density of benthons was 236.3 ind·m-2,and comate was the dominant species,with a ratio of 71.94% of the total inhabitation density.Besides,the total biomass of benthons was 53.0 g·m-2,and mollusk was the dominant species,with a ratio of 43.58% of the total biomass.The average diversity index and evenness of benthons were 2.62 and 0.83,respectively.Biodiversity indices showed that the area was at a lightly-moderate polluted status.Our results show a relatively higher quantity in biomass, inhabitation density,and diversity index and evenness in Hengqin Island sea area,as compared with other data from researches in the Pearl River Estuary.
We studied the toxic effect of algal toxin MCLR crude extraction,preliminary purified extraction and purified MCLR produced by laboratory-cultured Microcystis aeruginosa on mouse lymphocytes by using single cell gel electrophoresis(SCGE).The results showed that large amount of pigments and lipids in the crude extraction were removed by the n-hexane extraction in the preliminary process.When MCLR concentrations in crude extraction were higher than 66.2μg·L-1,DNA damages could be induced;whereas when MCLR concentrations in preliminary purified extraction were higher than 125μg·L-1,DNA damages were induced.The tail DNA% and OTM of preliminary purified extraction were slightly less than those of crude extraction.However,the damages of purified MCLR were much less than those of crude extraction.The damages for purified MCLR with the concentration of 494μg·L-1 were similar to those of crude extraction with 75.9μg·L-1 MCLR.Major parts of organic substances with UV adsorption,which were removed in the MCLR purification process,might bring about the significant differences between the crude extraction and purified MCLR.
Desert algae have a broad distribution in terrestrial environments,and the algae have been proved to be able to well adapt to extreme environments.Low temperature or cold stress is one of important ecological factors influencing survival of desert algae.In this study,a typical cyanobacteria species,Scytonema javanicum(Kütz.)Born et Flah,was isolated from desert algal crusts and selected as research material.In the experiments,2℃,10℃ and 28℃(as control)were selected for temperature treatments,and simultaneously low temperature domestication and exterior sugars such as sucrose and glucose were used to treat the algal cultures under different low temperatures.The results showed that low temperatures resulted in an obvious decrease in biomass and PS Ⅱ activity in S.javanicum. Low temperature domestication and exterior sugars promoted chlorophyll a content and PS Ⅱ activity of the alga to some extent,and low temperature domestication obviously increased intracellular production of water-soluble proteins;while no influence on MDA content was observed.In addition,we found that low temperature domestication evidently decreased secretion of EPS,but exterior sugars had no obvious role in relative osmotic activities of S.javanicum.The results suggest that low temperature domestication and exterior sugars may be crucial for tolerance of S.javanicum to low temperature or cold stress.
Evaluation of urban ecosystem health is urgently needed because it is the developmental basis of urban social-economic system.As a systematic analysis method to deal with uncertainty issues,Set Pair Analysis(SPA)is employed to evaluate the urban ecosystem health in this paper by taking Lanzhou as a case.We study the urban ecosystem by employing SPA from the index aspects consisting of productivity power,living status,ecological ascendancy and vital force,representing the situation of urban economic subsystems,social subsystem,natural subsystem,and ecological regulatory subsystem.The results show that healthy degree of Lanzhou city ecosystem rises continuously.Connection degree of health increased from 0.4751 in 2002 to 0.5179 in 2008,but generally the level is not high.The results can provide scientific reference for regional sustainable development.
By cluster analysis,the habitats of Tamarix chinensis in the Yellow River Delta are classified into three types:habitat with high salinity and drought condition,habitat with low salinity and drought condition,and habitat with low salinity and moist condition. Using point pattern analysis method,we analyze the spatial distribution rules of different habitats.Tamarix chinensis at different scales. The results show that in high salinity and drought habitat,as well as low salinity and drought habitat,the age class 2 T.chinensis is randomly distributed in all scales;while in low salinity and moist habitat,the age class 3 T chinensis is also randomly distributed in all scales.Distribution rules of other age class T.chinensis are significantly different in different habitats,indicating that in the Yellow River Delta the younger and senior age classes T.chinensis are able to adapt to ecological processes of water-salt balance by adjusting the spatial distribution patterns.The relationships among T.chinensis age classes in different habitats are more positively correlated,while some age classes have no relation at some spatial scales.
Coarse woody debris(CWD)is an important component in forest ecosystems and has a significant contribution to the maintenance of forest ecosystem health.A total of 17 plots each with 20 m×20 m in size were typically located and sampled throughout the Fenglin National Nature Reserve.Storage,diameter,length,and decay rank of CWD in broadleaved-Korean pine forest were investigated.The results are as follows.(1)The CWD storage of broadleaved-Korean pine forest amounted to 75.61 m3·hm-2,of which down logs,snags,stumps were 66.24 m3·hm-2,2.03 m3·hm-2,and 7.34 m3·hm-2,respectively.(2)The dominant diameter classes of down logs and snags were 11-20 cm(46%,of total CWD in quantity) and 0-10 cm(45%),respectively;the dominant length classes of down logs and snags were 0-5 m(66%) and 6-10 m(49%),respectively.(3)The distribution of decay classes of CWD presented approximately normal distribution,and mainly concentrated on classes Ⅱ(28%),Ⅲ(35%),and Ⅳ(26%).
To investigate ecophysiological adaptability of roof greening plant Sedum lineare of one,four,five and six years old,relative water content(RWC),mass per unit leaf area(LMA),and diurnal variation of gas exchange parameters in leaf were measured under drought condition in Guangzhou,China.Both RWC and LMA were low,and their values were 81.79% 87.58% and 0.0590.072 kg·m-2, respectively.S.lineare in different growth stages did not show significant change in leaf RWC and LMA(P<0.05).Gas exchange parameters including CO2 assimilation rate(A),stomatal conductance(gs),and transpiration(E)presented similar diurnal variation pattern in different growth stages of plant.There was also no significant variation in A,gs and E(P<0.05)in different growth stages.A, gs and E were significantly correlated with each other during a 24 h time-course(P<0.01).S.lineare is considered to be a facultative crassulacean acid metabolism(CAM) plant according to its characteristics of RWC and gas exchange parameters.There are similar major ecophysiological indices in 5.lineare in different growth stages.
Biodiversity informatics is an important part of biodiversity research.Information platform is of importance in biodiversity conservation and ecological education.Currently,researchers have carried out many investigations of biodiversity on a large scale in Beijing,but it is still lack of a systematic and comprehensive information platform.For biodiversity conservation and ecological education,we systematically analyzed and catalogued all the data from 2007-2009 based on the higher plants germplasm resources investigation and previous researches.Then we established the germplasm information query platform based on the database of species diversity inventory under the support of computer network technology.The share of higher plants germplasm resources information has been implemented by the platform,and users can accurately check detailed words and pictures information of 2586 species and varieties belonging to 149 families and 681 genera.The information includes classification of plant species,ecological characteristics, geographical distribution,conservation status,utilization,human disturbance and so on.The establishment of the platform can provide an important information support not only for protection and planning of plant resources,prevention and management of alien species,and resource utilization,but also for researches and ecological education in Beijing.
To investigate the change of cadmium accumulation in prostate glands of normal and castrated rats,sixty healthy male adult SD rats were randomly divided into six groups:control group,castration group,low dose cadmium group(2.5 mμmol•Kg-1),high dose cadmium group(20 mμmol•Kg-1),castration and low dose cadmium group(2.5 mμmol•Kg-1),and castration and high dose cadmium group(20 mμmol•Kg-1).The prostates of rats were sampled after 18 months of experiment.The cadmium content was measured by using atomic absorption spectrophotometry(AAS).The results showed that cadmium content in castration groups was significantly decreased than in non-castration groups.It was increased after peritoneal injection,but there was not statistical significance in different cadmium dosage groups.Our results showed that cadmium content was increased by long-term cadmium exposure;while it was not increased in castrated rats after long-term cadmium exposure.The underlying mechanism is not clear.
In order to achieve the soluble expression of Mn-SOD gene in E.coli,Mn-SOD gene was amplified from the genomic DNA of Bacillus subtilis ATCC 9372 according to the sodA gene sequence of B.subtilis 168.The cloned Mn-SOD gene was inserted into the expression vector pET-28a to be recombinant plasmid pET-28a-Mn-SOD and was then transformed for expression in E.coli BL21(DE3). The Mn-SOD protein with molecular weight of about 26 kD was expressed in E.coli after induction with isopropyl -β-D- thiogalactoside (IPTG),which accounted for approximately 35.6% of total bacterial protein.The enzyme activity of Mn-SOD was assayed with improved pyrogallic acid autoxidation method.The results showed that the specific activity of SOD in the total soluble protein was 51.09 U·mg-1,and was 4.84 times of control group.Mn-SOD gene of B.subtilis ATCC 9372 is first successfully expressed in E.coli BL21(DE3),and its products possess high dissolubility and enzyme activity.
Gas overrun due to increasing mining strength,depth and gas emission in the working face has become a major coal mining safety hazard.By employing similar material experiment and field test on multi-roadway in Sihe Coal high mining face,we put forward a ventilation type of intake air for three times and return air for two times,which can optimize ventilation system and solve the working face gas overrun problem in a certain extent.Multi-roadway layout in high efficiency working face is important in studying gas control technology.We preliminarily establish the framework for gas treatment in working face,which provides a valuable reference basis for gas treatment under the similar conditions.
The biological indicators of planktonic algae have been widely utilized in the field of monitoring and evaluating eutrophic state of different waters.In this paper,seasonal changes of planktonic alga composition were investigated to explore the relationship between planktonic alga indicators and the eutrophication characteristics of artificial lakes on four campuses in Beijing.During the investigation,39 genera of planktonic algae belonging to Chlorophyceae,Cyanobacteria and Bacillanophyta were identified.Seasonal average phytoplanktonic densities in four lakes were over 500 cell·ml-1.The biodiversity indices of four lakes across seasons were mostly between two and three.The water quality indicators,TN,TP and COD reflected that four lakes were all in eurtrophic state. However,the evaluation results on eutrophic levels were variable according to different indices.Therefore,cluster analysis was applied to combine the biological indicators and water quality indicators.The results showed that all of the seasonal waters could be classified into three different eutrophic types,according to the phytoplanktonic composition.The characteristics of phytoplankton community were most similar between Hehuachi and Hetang,while the eutrophic levels in summer were close between Hetang and Weiminghu.
We studied the variations of phytoplankton in Chaohu Lake in spring and summer seasons using enclosure experiments and field investigation from March to August,2009.The results showed that phytoplankton density and biomass in the enclosures were (2.95-102.43)×l05cells·L-1 and 0.06-7.39 mg·L-1,respectively.The dominant species were Anabaena sp.,Cyclotella meneghiniana, and Dinobryon cylindricum,with their maximal biomass of 0.82 mg·L-1,0.66 mg·L-1,and 2.98 mg·L-1,respectively,occurring in March or April.In spring(from March to May),the averaged phytoplankton biomass in Chaohu Lake was 5.43 mg·L-1.Chlorophytes contributed the most to the total algal biomass(47.59%),followed by Bacillariophytes(40.81%),and then Cyanobacteria(10.18%).The dominant species were Pediastrum sp.and C.meneghiniana.In summer(from June to July),the phytoplankton biomass in Chaohu Lake was averaged 7.89 mg·L-1.Cyanobacteria contributed 58.67% to total algal biomass,followed by Chlorophytes(26.77%) and Bacillariophytes(11.64%).The dominant species was Microcystis sp..Phosphorus and cladoceran grazing play important roles in the variations of phytoplankton biomass and community structure in Chaohu Lake in spring and summer seasons.
The effect of pretreatment.and preservation procedures on carbon and nitrogen stable isotope ratios of zooplankton Phyllodiaptomus tunguidus and Diaphanosoma orghidani transamurensis was studied.The results showed that gut contents in P.tunguidus led to a significant deviation in the values of replicates of both δI3C and δI5N.Lipid extraction resulted in a significant enrichment in δI3C and δI3N in P.tunguidus.Methanol and ethanol preserved animals showed higher δI3C values,while the frozen and formalin-preserved animals resulted in lower δI3C values.δI5N of two species was affected slightly,but not significantly,by four different preservations in this study.The results suggest that the variation from different treatments must be considered when making cross-study comparisons.Standard protocols for sample preparation and preservation are needed for the study of foodweb structure via stable isotope analysis.
Five extraction methods including Takara RNA,Tiangen kit,Invitrogen kit,modified CTAB-LiCl and CTAB-isopropyl alcohol method were compared for extracting total RNA from the leaves of four mangrove plants(Bruguiera gymnorrhiza,Kandelia candel,Aegiceras corniculatum,and Aricennia marina).The five methods were all suitable for total RNA extraction in leaves of A. marina.Tiangen kit was successfully used to extract the RNA in leaves of A.corniculatum,A.marina,and K.candel,but failed to extract the RNA in leaves of B.gymnorrihiza.Invitrogen kit extracted high quality RNA of 5.gymnorrihiza and K.candel,but could not remove the protein of leaves of A.corniculatum.The RNA amount extracted using CTAB-LiCl and improved CTAB-isopropyl alcohol methods was lower than using RNA extraction kits;besides,the efficiency of reverse transcription PCR of CTAB-LiCl and CTAB-isopropyl alcohol methods was lower.
Introduction and invasion of exotic plants are important global issues.Exotic plants can not only change the input and output of nitrogen,but also affect the nitrogen flows within terrestrial ecosystem through altering absorption and reuse of nitrogen,litter quality,soil microcosm and soil biota.Based on terrestrial nitrogen cycling framework,we reviewed the pathways and consequences that exotic plants affect terrestrial nitrogen cycling.Complexity of mechanisms,interaction of different nutrient cycling,and advanced technology should be considered in future research.
Ecology is a strong practical subject.Field practice teaching is one of important parts of this subject.According to main contents,research methods and features of ecology,location selection,operation of practical teaching,and assessment of practice quality were conducted by integrating the goal of higher education and specialized talents training,as well as the requirements of educational reform in ecology.This study can give some references to change the previous simple classroom-teaching focused on theoretical knowledge for students into the integrated teaching style of theories and practice skills and abilities.Additionally,this study can also provide some methods to conduct a more objective appraisal on quality of ecological synthetical field exercitation,and to mobilize students' learning activity and initiative.
