不同温度处理对金钟藤种子萌发的影响

主要研究了恒温25、28、30℃不同处理下温度对金钟藤种子荫发的影响，并采用发芽率、发芽指数、活力指数、芽长和胚根长等指标对金钟藤种子发芽效果进行了评价。结果表明，随着温度的升高，金钟膝种子发芽率、发芽指数、活力指数均上升。此外，随着温度的升高，芽和胚根出现不同的生长趋势，芽生长增加而根生长减少，进一步显示其地上部分受温度影响会加快生长，预示其入侵危害可能加剧。鉴于金钟膝日前在广州的危害情况，文章提出应将金钟滕列为潜在的入侵植物，加强研究，尽早开展预防和控制措施。     

源于大气的氟在水稻不同器官的分布及对糙米含氟量的影响

用开顶式熏气罩熏气的方法,研究了气源氟在水稻不同器官的分布及对糙米含氟量的影响。结果表明:气源氟主要分布于水稻叶片中,根含氟量不受气源氟的影响;籽粒含氟量取决于籽粒器官形成后空气氟浓度,与籽粒器官形成前的空气氟浓度无关;糙米氟含量与水稻抽穗齐穗后所暴露的氟剂量间呈极显著线性相关关系。     

Associations of trace elements in aerosol at the south Adriatic coast

We applied statistical methods to the data of a 5-year sampling period to characterize the features of trace elements in airborne particulate matter at the South Adriatic Coast. The analysis of surface soil samples was also performed. The data were processed by cluster analysis, enrichment factor determination and receptor rose statistics. It is shown that the principal element association consists of Fe, Mn and Ti originating from surface material resuspension. Hg and Se were shown to originate from more complex natural and anthropogenic processes. A strong emission source of Cd and Se was identified in the SSE direction.Selected article from the Regional Symposium on Chemistry and Environment Krusevac, Serbia, June 2003, organized by Dr. Branimir Jovancicevic.     

4个岷江柏种群的球果和种子形态特征及其地理空间差异

研究了我国四川和甘肃地区特有珍稀濒危植物岷江柏(Cupressus chenggiana S.Y.Hu)的4个地理种群球果和种子的形态特征，分析了不同生境条件下岷江柏的地理差异．结果表明：岷江柏球果呈椭球形，长(l)为1．5～2．5cm，宽(6)为1．5～2．0cm，重(m)为1．5～4．5g，球果鳞片数为8～11片，球果内种子粒数为40～70粒．在调查的4个岷江柏种群中，小金县种群的球果最大、球果内种子数最多，马尔康县种群和金川县种群的球果重量、球果内种子数居中，理县种群的球果最小、球果内种子数最少．讨论认为，4个种群球果和种子大小特征存在极显著差异，不同种群球果和种子的形态差异与岷江柏的种群遗传特征、气候特征和生境特征有着密切的关系．图3表7参25     

鼎湖山锥栗种子扩散过程中死亡因素分析

研究了锥栗(Castanopsischinensis)种子扩散过程中死亡的主要因素。实验分为无处理组、鸟类取食组、排除鸟类取食组、排除哺乳动物组和种子袋法。结果表明,扩散前种子主要受栗实象甲(Curculiodavidi)取食和病原体感染,其取食率在鼎湖山3种林型之间显示了较大差异。排除实验的研究表明,锥栗种子在扩散后承受啮齿类、鸟类等动物取食和病原体感染致死的巨大压力,其中无覆盖处理实验组的种子取食平均比例高达93.3%,鸟类对种子取食率约为80%,排除鸟类实验组中的种子平均取食率为92.4%,非哺乳动物对种子的取食在3个林型有差异,但不是显著性的。因此,巨大的种子死亡或丧失是锥栗自然更新率非常低的主要原因。     

不同电场对大豆种子萌发的影响

分别对大豆种子进行低压电场长期处理和高压电场短时处理 ,测定了不同电场处理后种子发芽势、浕 -淀粉酶和过氧化物酶活性、可溶性蛋白含量以及种子超弱发光的变化 .发现低压长期处理 (± 0 .2～ 1.0kV/cm ,每天 8h)对大豆种子的萌发没有明显影响 ,高压短时处理 (2～ 6kV/cm ,30min)能促进种子萌发 ,显著提高种子的发芽势、浕 -淀粉酶、过氧化物酶活性和可溶性蛋白含量 ,高压短时处理吸胀种子比处理干种子的效果更为明显 .短时高压电场处理后 ,种子的超弱发光明显增强 ,并且种子超弱发光的变化与生理生化指标的变化具有显著相关性 ,提示超弱发光有可能成为一种准确、快捷、灵敏筛选种子最佳电场处理剂量的物理指标 .图 1表 3参 17     

Clustering of aerosols in atmospheric turbulent flow

A mechanism of formation of small-scale inhomogeneities in spatial distributions of aerosols and droplets associated with clustering instability in the atmospheric turbulent flow is discussed. The particle clustering is a consequence of a spontaneous breakdown of their homogeneous space distribution due to the clustering instability, and is caused by a combined effect of the particle inertia and a finite correlation time of the turbulent velocity field. In this paper a theoretical approach proposed in Elperin et al. (2002) Phys Rev E 66:036302 is further developed and applied to investigate the mechanisms of formation of small-scale aerosol inhomogeneities in the atmospheric turbulent flow. The theory of the particle clustering instability is extended to the case when the particle Stokes time is larger than the Kolmogorov time scale, but is much smaller than the correlation time at the integral scale of turbulence. We determined the criterion of the clustering instability for the Stokes number larger than 1. We discussed applications of the analyzed effects to the dynamics of aerosols and droplets in the atmospheric turbulent flow.     

Effect of seed sludge on characteristics and microbial community of aerobic granular sludge

Aerobic granular sludge was cultivated by using different kinds of seed sludge in sequencing batch airlift reactor.The influence of seed sludge on physical and chemical properties of granular sludge was studied;the microbial community structure was probed by using scanning electron microscope and polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE).The results showed that seed sludge played an important role on the formation of aerobic granules.Seed sludge taken from beer wastewater treatment plant(inoculum A) was more suitable for cultivating aerobic granules than that of sludge from municipal wastewater treatment plant(inoculum B).Cultivated with inoculum A, large amount of mature granules formed after 35 days operation, its SVI reached 32.75 mL/g, and SOUR of granular sludge was beyond 1.10 mg/(g·min).By contrast, it needed 56 days obtaining mature granules using inoculum B.DGGE profiles indicated that the dominant microbial species in mature granules were 18 and 11 OTU when inoculum A and B were respectively employed as seed sludge.The sequencing results suggested that dominant species in mature granules cultivated by inoculum A were Paracoccus sp., Devosia hwasunensi, Pseudoxanthomonas sp., while the dominant species were Lactococcus raffinolactis and Pseudomonas sp.in granules developed from inoculum B.     

垃圾渗滤液对黑麦草和高羊茅种子萌发的影响

为了解垃圾渗滤液作培养液时草本植物种子萌发的情况。以黑麦草和高羊茅两种草本植物种子为研究材料,分别研究了垃圾填埋场渗滤液处理站的渗滤液原液、渗滤液生物处理出水以及渗滤液最终出水在6个不同配比的稀释溶液(V渗滤液/V蒸馏水=1/0,3/1,1/1,1/2,1/3,1/4)下对这两种种子萌发的影响。结果显示:随着渗滤液稀释强度的降低,种子的发芽势、发芽率、发芽指数和活力指数均增加,V渗滤液/V蒸馏水为1/3时,种子发芽率均为最高,黑麦草种子发芽率达96%,高羊茅种子发芽率达79%。用渗滤液作培养液时,更有利于黑麦草种子的萌发;用最终出水作培养液时,更有利于种子的萌发。这两种不同的渗滤液,在不同配比的稀释浓度下对种子的发芽率、发芽势、发芽指数和活力指数等均具有显著的生理作用。     

土霉素对小麦种子发芽与幼苗生长发育的生态毒性

研究了土霉素对小麦种子发芽以及早期幼苗生长发育的生态毒性效应.结果表明,土霉素对小麦种子芽长及根长的抑制效应显著(p<0.01),而且它们之间具有良好的剂量-效应关系.根据线性回归方程得出土霉素对小麦种子芽长和根长的半抑制浓度为65.5 mg/L和34.7 mg/L.然而,土霉素对小麦种子的发芽率并没有显著的影响.研究还表明,0.15~2.4 mg/L土霉素暴露21 d后,小麦叶片中的叶绿素含量降低了35.6%~47.3%,叶片及根部的可溶性蛋白含量也均呈显著下降趋势.暴露7 d后,0.15~2.4 mg/L土霉素对小麦叶片和根部SOD与POD活性的抑制效应不显著,但随着暴露时间的延长,土霉素对小麦的SOD与POD酶活性抑制率显著下降;2.4 mg/L土霉素暴露21 d后,小麦根部的SOD活性下降72.3%,说明土霉素对小麦幼苗体内的抗氧化系统具有破坏作用.该实验结果显示,低浓度土霉素长期暴露对小麦幼苗的生长发育具有不良的生态毒性效应.