安徽东至香隅化工园区域土壤重金属含量水平及污染评价

为研究安徽东至香隅化工园区域土壤重金属累积程度及其环境影响,在此区域采集5个表层土壤样本,分析测定了重金属Cd、Pb、Cr的含量,并用单因子指数法和潜在生态危害指数法进行了环境质量评价。结果表明：Cr含量超出背景值达10倍,富集程度高,但潜在生态危害指数较小;Cd的含量高出背景值2-3倍,富集程度低,但潜在生态危害指数最高;Pb也存在不同程度的污染。因此应合理引导区域开发活动,避免区域土壤环境污染加剧。     

Influence of spring preparation date and soil water content on seedbed physical conditions of a clayey soil in Sweden

Secondary tillage performed under inadequate soil water contents usually leads to a poor seedbed. Under normal Swedish weather conditions, clayey soils ploughed during autumn form a very dry top layer in spring, which acts as an evaporation barrier so that deeper layers remain wet. Thus, the conventional approach considering soil workability in relation to a single value of soil water content is difficult to apply. Hence, a field experiment was carried out to study the effect of seedbed preparation date, the associated soil water contents and traffic consequences on the physical properties of a spring seedbed. The field was autumn ploughed and the experiment started as soon as the field was trafficable after winter thawing. The seedbed preparation consisted of three harrowing operations on plots 8 m×8 m (three replications) with a spring tined harrow and a tractor mounted with dual tyres and was performed on 10 occasions from the beginning of April to the middle of May. With the exception of some short periods after rain, the soil had a clear water stratification during the experiment, with a very dry superficial layer (5–20 mm thick) contrasting to water contents over 300 g kg⁻¹ from only 40 mm depth. After the harrowing operation, the seedbed aggregate fraction less than 2 mm increased from about 40% at the beginning of April to about 60% for the last four treatments in May. Contributing factors to the rise were attributed to the lower water contents of the top layer (<40 mm) and the drying–wetting and freezing–thawing cycles that occurred in the surface layer during April. There were no significant differences in bulk density after harrowing between the treatments but an increase in penetration resistance up to a depth of 180 mm in the harrowed plots was statistically significant (P<0.001). In the non-harrowed soil, penetration resistance also increased, including in those soil layers where water contents kept nearly constant.

In conclusion, the seedbed preparation dates had only a minor effect on soil compaction, as measured by bulk density and penetration resistance, due to the slow drying beneath the dry top layer. The fraction of fine aggregates in the seedbed increased with time. Thus, the optimal time for seedbed preparation depended mainly on soil friability and not on the risk of compaction.     

抽穗后干旱复水对双季杂交晚稻产量形成和叶片δ13C及内源激素水平的影响

为探明生育后期干旱复水对双季杂交晚稻不同产量潜力品种产量的影响及其形成的生理机制,选择超级稻品种五丰优T025和对照品种金优207,于抽穗后进行干旱8d复水处理,分析了2个品种结实和产量、干旱前后倒二叶稳定碳同位素组成(δ13C)及内源激素含量的差异性。结果表明,干旱复水处理下2个品种水稻的结实率、千粒重及单株产量较对照(保持水层)表现出不同程度下降。其中,结实率五丰优T025和金优207分别下降12.07%和7.67%,千粒重下降5.23%和9.09%,单株产量下降13.54%和27.14%,差异均达显著或极显著水平,未发现产量补偿效应。抽穗后干旱处理下倒二叶δ13C值,五丰优T025大幅上升,复水后呈现出先下降,至第6天又开始上升的特点,金优207则大幅下降,复水后呈现先上升后下降再上升的特点,五丰优T025较金优207干旱复水处理与对照之间的差距更大。总体上,对照条件下,抽穗至其后20d,随生育推进,2个品种倒二叶内源ABA和GA₃含量呈上升而IAA含量则下降趋势,ZR表现出先上升再下降特点。干旱处理下2个品种表现为ABA含量上升,复水后呈先下降后上升特点,五丰优T025较金优207处理与对照之间差距更大;干旱复水处理条件下:2个品种IAA含量均下降,五丰优T025处理与对照间的差距明显小于金优207;五丰优T025 GA₃含量表现出先上升后下降再上升,金优207表现出干旱处理结束日急剧下降至最低点,复水后缓慢上升特点;2个品种ZR含量呈现出先上升至最高值再下降特点,五丰优T025较金优207处理与对照之间差距更小。抽穗后干旱处理将启动稻株体内抗衰老机制,复水后将在一定程度一定时间内激活稻株体内生长促进因子并抑制生长抑制因子,但其效果十分有限。     

宁南山区小流域雨水资源潜力与供需分析

根据宁南山区典型小流域土地利用现状和相关雨水集蓄资料,计算了彭阳王洼小流域雨水资源潜力,结合小流域节水农业发展规划,对雨水资源开发利用潜力及其供需关系进行了初步评价。结果表明:(1)示范区雨水资源最大理论潜力为7682598m3,就地利用、异地利用和叠加利用3种利用方式的比例分别为50.96%,7.16%和41.88%。(2)示范区雨水资源可实现潜力量为7164885m3,占全流域雨水资源理论潜力的93.26%。(3)目前示范区小流域的需水总量为3739352m3,仅占可实现供水量的52.19%,从示范区小流域雨水资源的可实现潜力来看,还有较大的开发利用潜力。(4)示范区小流域雨水资源利用评价结果表明小流域所制定的雨水利用规模对雨水资源的利用还很不充分,应适当地扩大雨水就地利用规模。     

京津冀地区农业土地资源潜力分类评价

在总结了国内外土地资源评价技术和方法的基础上,确定了土地潜力评价单元和指标体系,并对指标进行了分等和赋值;采用GIS技术和层次分析法,通过地图代数计算,对京津冀地区各农地类型的土地质量进行了评价划分。结果表明：除旱地外,一等地面积介于30%～50%;二等地面积均较大,除了草地为29.26%外,其他地类比例均超过50%,三等地和四等地面积均较小。总体看来,本地区农地以优质（一等地）和次优质（二等地）土地为主,农业土地资源总体情况尚好,但还有进一步改造挖掘的潜力空间。     

氮和磷对不同基因型小麦水分状况的影响

为了阐明不同水分条件下氮、磷对不同基因型小麦的水分生理指标的作用及其变化趋势，试验逸用6个不同基因型的小麦进化材料，研究了拔节期各基因型小麦的叶片保水力、叶水势、叶片膜透性与气孔导度。结果表明，当土壤水分充足时，施肥会提高叶片保水力、叶水势，降低叶片膜透性，增加二倍体小走的气孔导度，而降低六倍体小走的气孔导度。在水分胁迫下，施肥会提高叶片保水力，降低叶水势、叶片膜透性和气孔导度；而且随小麦染色体倍性从2n→4n→6n的进化方向，小麦叶片保水力、叶水势、叶片膜透性均先降低，然后又升高。     

Effect of Psammaplin A on in vitro Development of Bovine Aging Oocytes

To investigate the effect of histone deacetylation inhibitor Psammaplin A (PsA) on the development of bovine aging oocytes in vitro,oocytes were randomly divided into control group,aging group and 50 mmol/L PsA treated aging group (PsA group).Immunofluorescence staining and JC-1 were used to detect the blastocyst rate of bovine oocytes after parthenogenetic activation,the number of cells in blastocysts,apoptosis,reactive oxygen species (ROS),glutathione (GSH) and mitochondrial membrane potential intensity of embryos.The results showed that the blastocyst rate of the aging group was significantly lower than that of PsA and control groups (P<0.05).The blastocyst rate of PsA group was not significantly different from that of control group (P>0.05).The number of cells in the blastocysts of control group and PsA group were significantly higher than that of aging group (P<0.05).The number of cells in the blastocysts of PsA group was not significantly different from that of control group (P>0.05).The apoptosis rate in aging group was significantly higher than that of control and PsA groups (P<0.05),the apoptosis rate of PsA group was significantly higher than that of control group (P<0.05).The GSH level of MⅡ oocytes in aging group was significantly lower than that of control and PsA groups (P<0.05).There was no significant difference in GSH level between control and PsA groups (P>0.05).The ROS level of the embryos in aging group was significantly higher than that of control and PsA groups (P<0.05).The ROS level in PsA group was significantly higher than that of control group (P<0.05).The mitochondrial membrane potential of early embryos of aging group 4-8 cells was significantly lower than that of control and PsA groups (P<0.05).The mitochondrial membrane potential intensity of control group was significantly higher than that of PsA group (P<0.05).In summary,PsA could effectively delay the aging of bovine oocytes and improve the quality of oocytes.     

ISSR分子标记在入侵植物研究中的应用

\t\t\t\t\t目的 \t\t\t\t\t明确外来入侵植物大薸在云南的潜在适生区,为大薸的防控提供理论依据。 \t\t\t\t \t\t\t\t \t\t\t\t\t方法 \t\t\t\t\t采用最大熵生态位模型(MaxEnt)与地理信息系统(ArcGIS),结合大薸的地理分布数据、7个环境因子及4个地形因子,对其在云南的潜在分布和适生区等级进行预测。通过受试者工作特征(ROC)曲线方法进行验证,运用刀切法分析影响大薸分布的环境变量。 \t\t\t\t \t\t\t\t \t\t\t\t\t结果 \t\t\t\t\t大薸在云南省的适生区面积约13.56万km²,其中以滇中及滇南地区为主;生境主要为营养富集的水域、沼泽、沟渠和水田等。ROC曲线法得到AUC值为0.907,表明预测结果可靠。刀切法分析显示：影响大薸分布的主要环境因子为最冷季度平均温度、海拔和土地利用类型。\t\t\t\t\t \t\t\t\t \t\t\t\t \t\t\t\t\t结论 \t\t\t\t\t大薸在云南的潜在适生区面积较大,占云南国土面积的30%以上。 \t\t\t\t     

森林气候可能生产力的动态模拟

根据树森木材积的增长过程，建立了标准材积增长曲线，确定光能利用系数的时间演变。以地区辐射资料计算不同年龄的树木光合生产潜力，并利用湿润系数和日最高、最低温度建立了水分和温度订正函数，最终建立了森林气候生产力的动态模型。     

干旱条件下葡萄叶片气孔导度和水势与节位变化的关系

【目的】研究干旱条件下葡萄叶片气孔导度和水势随叶片节位变化的规律及其机理。【方法】利用3005F01植物水势测定仪和SC-1气孔计测量不同干旱程度下葡萄主梢各节位叶片气孔导度和水势。【结果】浇水良好的条件下,葡萄叶片气孔导度随叶片节位的升高而升高,且两者有很好的线性关系;轻度干旱可导致上部节位叶片气孔导度大幅度下降,而下部节位叶片气孔导度变化不大,叶片水势随着节位上升而提高;和轻度干旱相反,严重干旱时,叶片气孔导度随叶片节位的升高而下降,叶片水势仍然随着叶片节位的升高而上升,两者呈现出明显的线性关系。【结论】浇水良好的条件下,叶片气孔导度和叶片水势没有相关性;不同节位叶片对干旱的响应敏感度存在明显的差异,这种差异和叶片水势的变化及其反馈调节有密切的联系。