铝胁迫下不同耐铝小麦品种活性氧代谢差异及与小麦耐铝性的关系

逆境条件下植物体内产生并累积活性氧从而破坏植物组织结构与功能,同时植物也可以通过改变活性氧代谢相关酶活性清除活性氧而减轻活性氧伤害以适应环境胁迫。为研究铝胁迫下不同耐铝小麦品种（TriticumaestivumL．）在活性氧代谢上的差异及与小麦耐铝性的关系,本试验选用小麦品种ET8（耐铝型）、ES8（铝敏感型）为试验材料研究了不同耐铝小麦品种活性氧代谢变化上的差异。结果表明,50μmol·L-1铝处理24h,ET8和ES8活性氧含量显著升高,O2产生速率增幅分别为10．5％和20．4％,H202含量增幅分别为3．3％和7．6％。ET8和ES8超氧化物歧化酶（SOD）活性增幅分别为11．9％和41．6％,过氧化物酶（POD）活性增幅为51．8％和77．8％,抗坏血酸过氧化物酶（APX）活性增幅为54．4％和29．1％,过氧化氢酶（CAT）活性增幅为32．9％和38．4％,谷胱甘肽还原酶（GR）活性增幅为83．1％和85．5％。虽然抗氧化酶活性增加后会清除一部分活性氧,但活性氧的累积仍然造成了膜脂的过氧化,ET8和ES8丙二醛（MDA）含量分别增加18．2％和50．0％,质膜透性也随着MDA含量的升高而增加,增幅分别为1．25倍和1．36倍。综上所述,不同耐铝品种间活性氧代谢的差异是小麦品种耐铝性差异显著的原因之一。     

绵农小麦种子巯基蛋白酶抑制剂的纯化及性质研究

绵农11号小麦种子磨粉后的胚和麸皮，经溶液浸取和硫酸铵分级沉淀获得巯基蛋白酶抑制剂（CPI）粗品，再经木瓜蛋白酶－Sepharose4B亲和层析，DEAE－Sepharose离子交换层析和SephadexG－100分子筛层析，可获得两种CPI．通过SDS－PAGE或凝胶过滤法测得其Mr分别为18800［简称CPI（H）］和10500［简称CPI（L）］．它们在PAGE，SDS－PAGE和HPLC上均为单一蛋白带．CPI（L）和CPI（H）对木瓜白酶的抑制活性（ID50）分别为7．8×10－6mol／L和3．40×10－6mol／L．对无花果蛋白酶的抑制活性分别为9．5×10－5mol／L和5．8×10－6mol／L；CPI（H）对菠萝蛋白酶有弱抑制作用，但CPI（L）则无抑制作用；无论是CPI（L）或CPI（H）对胰蛋白酶、胰凝乳蛋白酶和胃蛋白酶均无抑制作用．CPI（H）的N－末端为Ile．CPI（H）和CPI（L）在pH2．0～11．0范围内和90℃处理5min，两种CPI的抑制活性均无变化；CPI（H）和CPI（L）对木爪蛋白酶的抑制曲线经Dixon作图法，得出CPI（H）为反竞争性抑制类型，而CPI（L）为竞争性抑制类型，其Ki值为8．32×10－6mol／L．     

粗壮女贞中的新单萜配糖体

从粗壮女贞（Ｌｉｇｕｓｔｒｕｍ ｒｏｂｕｓｔｕｍ）叶子中分离鉴定了４个新的单萜配糖体,命名为粗壮女贞甙Ｄ、Ｇ、Ｈ和Ｌ．通过滤谱及化学方法,它们分别鉴定为香叶醇３‘－Ｏ－μ－Ｌ－南鼠李糖基－４’－顺式香豆酰基－β－Ｄ－吡喃葡萄糖甙（１）,６－羟基－３,７－二甲基－２Ｅ,７葵二烯醇３‘－Ｏ－α－Ｌ－吡喃鼠李糖基－４’反式香豆酰基－β－Ｄ－吡喃葡萄糖甙（２）,６－羟基－３,７－二甲基－２Ｅ,７－葵二烯醇     

腺叶香茶菜的化学成分研究

从腺叶香茶菜［Rabdosiaadenoloma（Hand．－Mazz．）Hara］地上部分的乙醇提取物中共分离出10个化合物．经EIMS、1HNMR和13CNMR等波谱和化学方法分别鉴定为：effusaninA（1）、effusaninE（2）、洋芹素－4＇，7－二甲醚（3）、β－谷甾醇（4）、柳杉二醇（5）、Uvaol（6）、白桦酸（7）、齐墩果酸（8），乌苏酸（9），齐墩果酸－3－O－α－L－鼠李吡喃糖基（1→2）［β－D－葡萄吡喃糖基－（1→4）］－α－L－阿拉伯吡喃糖甙（10）．其中8的含量高达1％以上．上述化学成分均为首次从该植物中分离得到．     

曲霉WZ-2对染料脱色研究

从废水池污泥中分离到一株染料脱色曲霉ＷＺ－２,它对不同染料均有较好的脱色效果。在３３￣４０℃温度范围内ＷＺ－２对活性桃红ＫＤ－８Ｂ的脱色率为８４％￣９８％,最佳脱色温度为３３℃,ｐＨ值在４．０￣７．０范围内ＷＺ－２对直接耐晒翠蓝ＧＬ的脱色率为８３％￣９６％,最佳脱色ｐＨ为６．０,碳源、氮源及接种量对其脱色率均有影响,染料脱色物的紫外－可见光谱分析表明,可见光区５２０ｎｍ处的吸收峰完全消失,而紫外光     

二正烷基亚硝胺第二活性区对致癌作用机理的理论研究

采用ＭＮＤＯ方法计算了对称二烷基亚硝胺β－,γ－和δ－位硫酸酯经ＳＮ２反应机制与ＤＮＡ碱基腺嘌呤（Ａ）发生烷化反应的速率控制步骤的势能曲线和活化能,以及β－位硫酸酯经邻基参与作用的腺嘌呤烷化反应过程的势能变化。结果表明,邻基参与作用有利于促进了烷基亚硝胺与ＤＮＡ的烷化反应,提高了β－位硫酸酯烷化ＤＮＡ的能力,以此可以解释β－位硫酸酯化的二烷基－Ｎ－亚硝基化合物的致癌活性大于γ－和δ－位硫酸酯化的二     

硝化菌群在不同条件下的增殖速率和硝化活性

研究了不同环境因子变化对硝化菌群的增殖能力及其对硝化作用活性的影响,确定了硝化菌群的最佳生长条件．研究发现,温度（θ／℃）、ｐＨ、供氧状况、无机碳源浓度等对于硝化细菌菌群的增殖能力及硝化作用活性具有较重要的影响,而含盐量高低几乎无影响．最适（θ、ｐＨ、［ρ（Ｏ２）］、［ρ（ＮａＨＣＯ３）］分别为３０℃、ｐＨ８．５、３．５ｍｇＬ－１、１ｇＬ－１,此时最大比生长速μｍ可达５．１８ｄ－１,最大比降解速υｍ可达４８．４３ｈ－１．在含氧量较低时,氨氮浓度的升高使硝化菌群的μ值下降,υ值上升．考察有机碳对该菌群的影响发现,ｍ（Ｃｏｒｇ）ｍ－１（Ｎ）在０～０．５之间时,菌群有较大的比生长速率,并且硝化作用活性增强     

太湖水-沉积物界面磷、pH及碱性磷酸酶的时空特征及相关性

于2011年3、6和9月通过对太湖不同营养化湖区的5个标准采样位点进行采样分析,探讨了界面沉积物间隙水和上覆水中磷含量、pH及碱性磷酸酶活性的时空分布特征及相关性。结果表明,上覆水及沉积物间隙水中的总磷（TP）、可溶性正磷酸盐（SAP）、pH及碱性磷酸酶（ALP）活性均表现出明显的空间异质性和季节变化趋势。间隙水总磷（PW-TP）、间隙水可溶性正磷酸盐（PW-SAP）高于上覆水,分别最高高出0．082、0．042mg·L-1;上覆水pH值高于间隙水pH值,最高高出O．35个单位;间隙水中碱性磷酸酶（PW-ALP）活性高于上覆水中碱性磷酸酶（W-ALP）活性,最高高出13．244μg·mL·h-1。TP、SAP、pH及ALP活性在3、6、9月份中均以16#样品最高,其中6月份16#样品PW-TP、PW-SAP、上覆水pH及PW-ALP活性分别O．527、0．132、7．46和61．090μg·mL·h-1。参数相关性分析结果表明,W-TP与W-SAP、W-pH显著相关。W-SAP与PW-TP、PW-SAP、W-ALP、PW-ALP均显著相关。PW-TP与PW-pH显著相关性,与PW-ALP活性存在一定的相关性,但不显著。PW-SAP与PW-ALP显著相关。     

小麦内切多聚半乳糖醛酸酶抑制蛋白的部分性质研究

报导了小麦ＰＧＩＰ的部分性质，小麦ＰＧＩＰ是一种糖蛋白，含糖量６．８９％，对热不稳定，等电点为９．１和９．４，它抑制ｅｎｄｏ－ＰＧ的最适ｇＨ是４．０￣５．５，测定了ＰＧＩＰ亚基的氨基酸组成，ｐＨ、离子强度和温度对ＰＧＩＰ活性的影响。     

线扫极谱法快速测定鱼组织中的金属硫蛋白

本文报告了用线扫极谱法测定鱼组织中金属硫蛋白（ＭＴ）的分析方法，其主要步骤是将鱼将成匀浆，加热变性除去杂蛋白，离心后取上清液直接加入钴氨液中，记录－１．４６Ｖ（ｕｓ ＳＣＥ）处峰形，由峰高求得ＭＴ浓度。本文给出ＭＴ标准波形，凝胶过滤分离－峰电流图谱，干扰因素及其浓度，检出量和回收率，最后求得鲫鱼六种组织中ＭＴ的本底值和经Ｃｄ（Ⅱ），Ｈｇ（Ⅱ）和Ｃｒ（Ⅵ）诱导后的实测值。结果表明本方法具有快速、灵敏     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).