Is The Ca + K + Mg/Al Ratio in the Soil Solution a Predictive Tool for Estimating Forest Damage?

The ratio between (Ca +K +Mg) and Al in nutrientsolution has been suggested as a predictive tool forestimating tree growth disturbance. However, the ratiois unspecific in the sense that it is based on severalelements which are all essential for plant growth;each of these may be growth-limiting. Furthermore,aluminium retards growth at higher concentrations. Itis therefore difficult to give causal and objectivebiological explanations for possible growthdisturbances. The importance of the proportion ofbase-cations to N, at a fixed base-cation/Al ratio, isevaluated with regard to growth of Picea abies.The uptake of elements was found to be selective;nutrients were taken up while most Al remained insolution. Biomass partitioning to the roots increasedafter aluminium addition with low proportions of basecations to nitrogen. We conclude that the low growthrates depend on nutrient limitation in thesetreatments. Low growth rates in the high proportionexperiments may be explained by high internal Alconcentrations. The results strongly suggest thatgrowth rate is not correlated with the ratio in therooting medium and question the validity of usingratios as predictive tools for estimating forestdamage. We suggest that growth limitation of Picea abies in the field may depend on lowproportions of base cations to nitrate. It istherefore important to know the nutritional status ofthe plant material in relation to the growth potentialand environmental limitation to be able to predict andestimate forest damage.     

Does Soil Acidification Affect Spruce Needle Chemical Composition and Tree Growth?

In 1994, a large survey of soil chemistry was undertaken in thecounty of Värmland in central Sweden (Lundström et al., 1998).The southern part of the county was affected by soilacidification whereas there were no such indications in thenorthern part. To investigate the influence of soil chemistryon the trees at the specific sites, the survey was continued byan analysis of needle chemistry (Norway spruce) which wasundertaken at 150 of the 180 sites, and of tree growth at 65 ofthe 180 sites. Growth was expressed as a ratio between expectedgrowth, estimated with a national, empirical growth model, andthe growth observed in the field. In statistical analyses,using rank correlation, PCA and PLS, there were only weakindications of an influence of soil chemistry on needlechemistry and on tree growth. A moderate correlation betweennitrogen and sulphur in needles was found, which wasinterpreted as an effect of deposition and of processes in thetree canopy. No obvious regional pattern of the growth ratiowas found, in contrast to the clear pattern of soilacidification. The statistical analysis could not with anycertainty point out any of the soil chemistry variables asespecially important for the tree growth ratio.     

Urban expansion and its contribution to the regional carbon emissions: Using the model based on the population density distribution

The method is used for calculating regional urban area dynamics and the resulting carbon emissions (from the land-conversion) for the period of 1980 till 2050 for the eight world regions. This approach is based on the fact that the spatial distribution of population density is close to the two-parametric Γ-distribution [Kendall, M.G., Stuart, A., 1958. The Advanced Theory of Statistics, vol. 1.2. Academic Press, New York; Vaughn, R., 1987. Urban Spatial Traffic Patterns, Pion, London]. The developed model provides us with the scenario of urbanisation, based on which the regional and world dynamics of carbon emissions and export from cities, and the annual total urban carbon balance are estimated. According to our estimations, world annual emissions of carbon as a result of urbanisation increase up to 1.25 GtC in 2005 and begin to decrease afterwards. If we compare the emission maximum with the annual emission caused by deforestation, 1.36 GtC per year, then we can say that the role of urbanised territories (UT) in the global carbon balance is of a comparable magnitude. Regarding the world annual export of carbon from UT, we observe its monotonous growth by three times, reaching 505 MtC. The latter, is comparable to the amount of carbon transported by rivers into the ocean (196–537 MtC). The current model shows that urbanisation is inhibited in the interval 2020–2030, and by 2050 the growth of urbanised areas would almost stop. Hence, the total balance, being almost constant until 2000, then starts to decrease at an almost constant rate. By the end of the XXI century, the total carbon balance will be equal to zero, with the exchange flows fully balanced, and may even be negative, with the system beginning to take up carbon from the atmosphere, i.e., becomes a “sink”. The regional dynamics is somewhat more complex, i.e., some regions, like China, Asia and Pacific are being active sources of Carbon through the studied period, while others are changing from source to sink or continue to be neutral in respect the GCC.     

Quantifying Plant Population Persistence in Human-Dominated Landscapes

Abstract:  We assessed population performance of rare plants across a gradient from rural to urban landscapes and evaluated 2 hypotheses central to strategic conservation planning: (1) population performance declines with increasing human dominance and (2) small populations perform poorly relative to larger ones. Assessing these hypotheses is critical to strategic conservation planning. The current conservation paradigm adheres to the well-established ecology theory that small isolated populations, particularly those in human-dominated landscapes, are the least likely to succeed over the long term. Consequently, conservation planning has strongly favored large, remote targets for protection. This shift in conservation toward ecosystem-based programs and protection of populations within large, remote systems has been at the expense of protection of the rarest of the rare species, the dominant paradigm for conservation driven by the endangered species act. Yet, avoiding conservation of small populations appears to be based more on theoretical understanding and expert opinion than empiricism. We used Natural Heritage data from California in an assessment of population performance of rare plants across a landscape with an urban-rural gradient. Population performance did not decrease in urban settings or for populations that were initially small. Our results are consistent with a pattern of few species extinctions within these landscapes over the past several decades. We conclude that these populations within compromised landscapes can contribute to overall biodiversity conservation. We further argue that conservation planning for biodiversity preservation should allocate relatively more resources to protecting urban-associated plant taxa because they may provide conservation benefit beyond simply protecting isolated populations; they may be useful in building social interest in conservation.     

九寨沟自然保护区4种水深梯度下芦苇分株地上生物量的分配与生长

芦苇是世界自然遗产--九寨沟自然保护区的一种重要的湿地植物.本文对该地区芦苇海4个不同水深梯度下芦苇的无性系地上分株的生物量分配、生长与繁殖策略进行了比较研究.结果表明,在47 cm (水在土层表面上)水深环境中,芦苇单株的平均生物量(4.2 g)最大.在-15 cm (水在土层表面下15 cm)的生境中,叶生物量百分比(叶生物量占单株总生物量的百分比, 46.1%)最大.芦苇地上分株高度、地上分株有分枝的单株百分比(茎上有分枝的分株占样地总分株的百分数)也存在明显的差别.茎的生物量分配百分比和生长速率随水深的增加而增加.在滩地生境中,开花率、花序的生物量百分比明显大于水较深的生境.分株株高与分株生物量、茎生物量与叶生物量都表现出较明显的幂指数异速生长规律.在-15 cm水深的生境中,叶生物量的生长快于茎的增长;在其他水深梯度的生境中,则是茎生物量的增加快于叶生物量的增加.     

海洋硅藻三角褐指藻经黑暗与UV辐射后的补偿生长(英文)

补偿生长是生物体对环境变化的一种适应性反应,主要指生物体遭受到不良环境胁迫后其生长及生理机能受到制约,但当不良环境胁迫解除后,生物体的生长能力会得到不同程度的恢复,表现出相对未受不良环境胁迫生物体超常生长的现象.迄今为止,补偿生长研究的对象主要集中在水生动物、反刍动物和高等植物上,而针对体积微小的海洋浮游植物的研究非常有限.海洋微藻是海洋生态系统最主要的初级生产者,在自然界物质和能量流动中扮演着至关重要的角色;同时,它们可以广泛应用在水产养殖、食品加工、医药保健、环境保护和生物制能等各种行业,具有非常好地开发利用前景.本文利用海洋硅藻三角褐指藻为试验材料,设置黑暗胁迫和UV辐射胁迫处理,着重测定微藻在恢复生长时期的藻生物量,叶绿素a含量和蛋白质含鼍等指标,探讨经黑暗与UV辐射胁迫后三角褐指藻的补偿生长现象.结果显示,无论是先经正常光照处理还是2 d黑暗处理,UV辐射0.1 rain和0.8 rain的微藻生物量都明显高于不经UV辐射胁迫的微藻生物置;此外,经过不同程度的黑暗与UV辐射处理后,微藻在恢复生长期的叶绿素a和蛋白质含量在某特定生长时期中明显高于对照组的叶绿素a和蛋白质含最.结果表明,三角褐指藻对外界环境变化具有适应能力,一旦不良环境胁迫被解除,微藻会表现出一定的补偿生长效应.我们的研究结果不但拓展和丰富了目前补偿生长的研究对象范围,而且还能为当前赤潮的形成、预测和防治提供一个新的研究思路,为有益经济微藻的高效率培养与利用提供理论指导.     

模拟氮沉降对大豆萌发和幼苗生长的影响

氮沉降是当今倍受关注的全球性环境问题.采用大田试验和室内培养的方法,研究大豆种子萌发和幼苗生长对氮沉降的响应.实验设4组处理(CK、T1、T2、T3),所施氮肥为NH4NO3,在室内培养实验中,4组处理的浓度分别为0、0.08、0.16、0.24mol/L.大田实验中,4组处理的氮施入量分别为0,50,100,150 kg·hm-2·a-1.结果表明:过量氮沉降对种子萌发有一定的抑制作用,降低了种子的发芽速度和发芽率;抑制了幼苗的生长速度,降低了植株的株高、叶面积和生物量,并减小了根冠比;随着氮施入量的增加幼苗的蒸腾速率逐渐降低,但叶片叶绿素含量逐渐增加.     

微囊藻毒素在细长聚球藻中的积累及其毒性效应

用 100μg/L 的微囊藻毒素(MC-RR)处理细长聚球藻,研究了 MC-RR 在藻细胞中的积累及其对细长聚球藻的生长和抗氧化系统的影响.结果表明,MC-RR 能在细长聚球藻中迅速积累,而细长聚球藻具有较强的降解 MC-RR 的能力,MC-RR 对细长聚球藻的生长具有显著的抑制作用;MC-RR 处理后,活性氧(ROS)和膜脂过氧化产物丙二醛(MDA)含量明显升高,还原型谷胱甘肽(GSH)含量和谷胱甘肽 S-转移酶(GST)、谷胱甘肽过氧化物酶(GPX)活性则有一个先降后升的变化.以上结果说明,细长聚球藻细胞在 MC-RR 处理下,膜脂过氧化加剧,受到氧化胁迫;GSH、GST、GPX 在清除活性氧,抵抗 MC-RR 的毒性伤害中发挥着关键的作用.     

吸附-降解组合生物系统处理含铜离子城市污水

采用Pseudomonas putida 5-x细胞为吸附剂的生物吸附过程组合SBR生物降解系统处理含铜离子城市废水.研究了生物吸附剂Pseudomonas putida 5-x细胞的最佳制备条件以及组合系统的运行过程.实验结果表明,在优化的条件下,Pseudomonas putida 5-x细胞对铜离子的吸附容量可达87.3mg·g^-1,经生物吸附处理后,污水中Cu²⁺的含量显著降低,尽管残留的Cu²⁺对活性污泥吸附COD的能力尚有一定影响,但已不影响SBR系统对废水中COD的去除效果.研究表明,在活性污泥法处理含铜离子废水前,采用生物吸附技术降低废水中Cu²⁺含量,有利于提高后续活性污泥过程对COD的去除能力.     

ClO2和碳水化合物水平对中国明对虾存活和生长的影响

研究了盐度为5条件下,ClO2和碳水化合物水平对中国明对虾(Fenneropenaeus chinensis)存活和生长的影响,共两个实验:实验1研究了ClO2(0、1、4、7、10、13、16、19和22 mg/L)对中国明对虾存活的影响,发现随ClO2浓度的升高,对虾存活率呈下降趋势;在24、48、72和96 h,LC50分别为21.04、13.32、10.91和8.26 mg/L,安全浓度为1.60 mg/L.实验2研究了ClO2(0.0、0.2、0.4和0.6 mg/L)和饲料中碳水化合物水平(13.89和41.76%)对中国明对虾存活和生长的影响,发现在两个碳水化合物水平,随ClO2浓度的升高,对虾存活率、特定生长率、摄食量和吸收效率均呈下降趋势,而饲料系数呈上升趋势;在四个ClO2水平,摄食13.89%碳水化合物对虾的特定生长率、摄食量和吸收效率均高于摄食41.76%碳水化合物的对虾,而摄食13.89%碳水化合物对虾的饲料系数低于摄食41.76%碳水化合物的对虾.