南京市植物叶面颗粒物的黑碳含量及时空分布特征

黑碳是大气气溶胶的重要组成部分,能够吸收太阳辐射产生温室效应,并对人体健康产生负面影响。选取了南京市的6个典型功能区,研究不同污染水平和不同季节下植物叶面颗粒物黑碳含量的时空分布特征,并将其与地面尘和表层土壤中的黑碳含量进行比较,探讨黑碳在多介质中的分布规律。结果表明:(1)城市植物叶面颗粒物的黑碳含量呈现冬季秋季春季≈夏季的季节变化特征;(2)工业区植物叶面颗粒物的黑碳含量最高,并与其他功能区的差异达显著水平;(3)城市植物叶面颗粒物黑碳含量越高,BC/OC值也越大,城市植物叶面颗粒物的黑碳主要来源于化石燃料的燃烧;(4)黑碳气溶胶通过植被表层到达地表的过程中其含量逐渐下降,植物叶面颗粒物可作为监测大气黑碳污染的有效手段。     

Susceptibility of Eucalyptus globulus to Mnesampela privata defoliation in relation to a specific foliar wax compound

Summary. Increased abundance of several aliphatic benzyl and phenylethyl alkanoates were previously associated with reduced defoliation of Eucalyptus globulus Labill. by the autumn gum moth (Mnesampela privata Guenée) in two clonally replicated F₂ families. We examine the robustness of this association by comparing the abundance of the implicated foliar wax compounds with defoliation levels in three plantation sites and a genetics trial in northern Tasmania. At all locations, the aliphatic alkanoate, benzyl n-tetracosanoate (C₂₄), was found in significantly higher abundance in the foliar wax of E. globulus trees that had displayed low M. privata damage (designated resistant) compared to trees that had displayed high damage (designated susceptible). Further, when sites were combined, benzyl n-tetracosanoate (C₂₄) accounted for 16 % of variation in field defoliation. Field defoliation was also positively correlated to M. privata oviposition both in the field and on foliage sprigs in a cage. In the cage bioassay, oviposition accounted for 20 % of variation in field defoliation making it a better predictor of tree defoliation in the field than either field oviposition, which accounted for 9 % of variation, or screening foliage for the abundance of benzyl n-tetracosanoate (C₂₄). Despite both benzyl n-tetracosanoate (C₂₄) and oviposition being related to field defoliation, there was no statistically significant relationship between the abundance of benzyl n-tetracosanoate (C₂₄) and oviposition in the field or cage bioassay. Further work is therefore required to determine if increased levels of this compound in the foliar wax operates as a direct deterrent to M. privataoviposition.     

Early Effects of Atmospheric Ammonia Deposition on Calluna Vulgaris (L.) Hull Growing on an Ombrotrophic Peat Bog

This paper reports data from a field study investigating the impacts of elevated ammonia (NH₃) deposition on Calluna vulgaris growing on an ombrotrophic peat bog in S.E. Scotland. Shoot extension, foliar N concentrations, chlorophyll concentration and chlorophyll fluorescence were measured during the second growing season of exposure to a gradient of ammonia concentrations. Results indicate that NH₃ increases growth between 150–200 kg N ha^–1y^–1 cumulative deposition. Foliar N content increased significantly in response to NH₃ cumulative deposition up to 400 kg N ha^–1 y^–1 whereas chlorophyll a content significantly decreased. Measurements of Fv/Fm suggest that although NH₃ exposure altered the growth and reduced chlorophyll a, the efficiency of photosystem II was insensitive to NH₃-N deposition at this stage.     

Field Surveys of Ozone Symptoms on Spontaneous Vegetation. Limitations and Potentialities of the European Programme

Within the European intensive forest monitoring programme, the native vegetation on permanent Level II plots has been monitored for visible ozone injuries. The main purpose of the programme is to assess the potential risks for the forest vegetation and the natural ecosystems at the intensive monitoring plots. During the first years of the programme the surveys were qualitative, reporting only the number and the name of the symptomatic species in selected Light Exposed Sampling Site. In 2003 a new plot design was tested, based on the distribution of a number of miniplots along the edge of the forest, so as to obtain quantitative findings about the occurrence and distribution of the symptoms. The problems that still persist are related to: (i) the forest edge assessed for ozone symptoms may have a different floristic composition from the Level II plot itself; (ii) the anthropic pressure and the disturbances affecting the forest edge alters the floristic composition; (iii) the variability of the plant composition in the forest edge, which makes comparability difficult between different sites; and (iv) the evaluation of symptoms in several species that have not yet been experimentally tested. Further difficulties are due to the fact that symptoms observed in the field are often aspecific and cannot, therefore, be attributed solely to the phytotoxic action of ozone. To improve the effectiveness of the European programme, it is necessary: (i) to individualise and select common sensitive plant species for homogeneous ecological regions; (ii) to enhance experimental activities to test the sensitivity of a large number of plant species.     

土壤和叶面施锰联合钝化剂降低稻米镉的综合效应

镉（Cd）污染酸性稻田存在严重的环境和健康问题,常采用碱性钝化剂和拮抗剂锰（Mn）肥来降低水稻Cd污染.然而,Mn的生物有效性可能会受到钝化剂影响而不能有效降低稻米Cd的累积.采用一种含有机质和硅钙的碱性复合钝化剂,联合土壤施用硫酸锰拮抗剂,并在水稻孕穗期和灌浆期叶面喷施有机锰肥（EDTA-Mn、氨基酸锰）,研究其联合施用效果和机制.在盆栽试验中,选择3种处理模式：土壤施用钝化剂/锰肥（T）;叶面喷施锰肥（Y）;土壤钝化剂、锰肥、叶面锰肥配合施用（T+Y）,共计12个处理.在田间试验中,选择两种处理模式：单施叶面锰肥（Y）;土壤钝化剂、锰肥、叶面锰肥配合施用（T+Y）,共计9个处理.盆栽试验结果表明,与对照CK相比,单施钝化剂、 单施硫酸锰、1/2钝化剂+1/2硫酸锰处理稻米Cd含量分别降低了19.1%、44.0%和51.9%.在1/2钝化剂+1/2硫酸锰的基础上,叶面锰肥EDTA-Mn、氨基酸锰使稻米Cd进一步降低了46.1%和46.9%.田间试验结果表明,与CK相比,EDTA-Mn、氨基酸锰二种叶面锰肥配合1/2钝化剂+1/2硫酸锰分别使稻米Cd降低了86.9%和83.6%,Cd富集系数均降低到0.05.单施钝化剂显著提升了盆栽土壤pH,并使土壤CaCl₂-Cd显著降低.然而,单施钝化剂抑制了根表锰膜的形成,而1/2钝化剂+1/2硫酸锰显著提升根表铁锰膜,使根表固定更多的Cd.叶面喷施锰肥显著降低Cd由茎叶向稻米的转运.田间试验也显示,1/2钝化剂+1/2硫酸锰配合叶面锰肥虽然提升土壤pH和降低CaCl₂-Cd不如高量钝化剂的处理,但显著降低Cd由茎叶向稻米的转运.综上所述,盆栽试验和田间试验均表现出1/2钝化剂+1/2硫酸锰配合叶面喷施有机锰肥能全方位阻控水稻对Cd吸收转运,有效降低稻米Cd的累积.     

钝化与叶面阻控对不同基因型红菜苔镉累积的影响

为探索中轻度重金属镉(Cd)污染农田安全利用技术,实现农产品安全生产,以两种不同镉累积基因型红菜苔为供试作物,采用盆栽试验的方法,分别于两种作物上设置相同的6个处理:对照(CK)、添加3℅(质量分数)生物质炭(BC)、添加0.17℅ 钙镁磷肥(CMP)、叶面喷施3 mg·L-1 Na2 SeO3的水溶液(Se)、BC+...     

叶面施硒对水稻砷吸收积累影响的研究进展

硒对作物吸收重金属元素的影响,是土壤污染区能否生产富硒低重金属农产品的理论基础。在分析叶面施硒优缺点的基础上,重点分析了叶面施硒对水稻砷吸收、积累和再分配过程的可能影响途径。对叶面喷施的硒而言,叶片对硒的吸收和再分配能力、叶片硒在水稻体内的迁移和再积累过程、叶片硒在根部迁移积累和外排效应对水稻根部砷吸收、向上迁移和积累的影响是决定水稻砷富集的关键过程,施硒形态、施硒量和施硒生长期是影响砷积累的关键因素。并对未来的研究方向进行了展望。     

城区叶面尘特性及其多环芳烃含量

用多步连续洗脱方法采集了干线道路路侧和远离道路校园内冬青卫矛叶面积尘,研究了叶面尘的采集方法.测定了2类叶面尘的粒径分布、有机碳含量和多环芳烃含量.结果表明,所测样品上的叶面尘可以在超声条件下4min一步洗脱.路边样品叶面尘积累量几乎是校园样品的2倍.2样品粒径分布基本形态非常相似,包括200μm以上和以下2个组分.后者占绝对优势.但校园内样品叶面尘粒径明显小于路边样品,两者粒径中位数分别为17.2μm和23.1μm.路边样中相对较粗部分显然来自机动车行驶扰动.由于颗粒较细,采自校园叶面尘中多环芳烃含量略高于路边样品.但不同多环芳烃分布谱非常相似.     

叶面喷施硫对镉污染土壤中水稻累积镉的机制研究

Cd（镉）污染稻田已成为影响全球农田土壤环境安全的重要问题,叶面喷施技术可以提高水稻对Cd的抗性,减少其对Cd的累积,保证农产品质量安全、维护土壤生态功能、防范环境和人体健康风险.通过两年四季的湖南省长沙县田间试验,探索叶面喷施S（以Na₂S计）在中轻度Cd污染稻田中的降镉、增产效果及其可推广性,进而设计水培试验,探究相关机制.结果表明:田间试验中,叶面喷施S可以将水稻产量提高6%~30%,水稻籽粒w（Cd）降低28%~50%.叶面喷施S能够增加水稻叶片的捕光能力和电子传递速率,与对照组相比,净光合速率提高2%~25%、气孔导度提高7%~25%、胞间CO₂浓度提高2%~10%、蒸腾速率提高1%~11%;实际光化学效率提升3%~21%,也可在一定程度上减缓光合系统结构和功能受到的损伤,同时提高光合作用碳同化的效率,提高水稻产量.傅里叶变换红外光谱图显示,叶面喷施S通过增强有机大分子类物质（如有机酸、多肽类等）的生成,可能直接与Cd发生螯合,区隔在细胞壁或者液泡上,降低Cd的侵害.研究显示,叶面喷施S在Cd胁迫水稻中积极参与生化过程的特定光合作用和蛋白质合成的调节,减轻了水稻Cd胁迫,可以尝试在同类型重金属污染农田土壤中推广.      

植物叶面吸收污染物机制研究进展

庞大的植被是大气污染物进入地表系统的重要过滤层,植被表面是污染物与植物相互作用的界面,大气污染物跨叶面进入植物体的运输行为对解释其环境效应至关重要.植物不仅能有效地消减城市大气污染,还可用作被动采样器动态监测不同时空尺度上大气污染的水平与特征,两者均须通过叶面吸收的方式得以实现.气孔与角质层是植物叶面吸收污染物的两种主...