都江堰灵岩山3种人工林优势物种叶片的有机组分特征

叶片的有机组分特征不仅是植物光合产物分配策略和养分回收的重要参数,而且是衡量凋落叶分解难易程度的重要指标.为探究不同植物群落叶片间有机组分的差异,以华西雨屏区人工林的优势乔、灌、草植物作为对象,收集其成熟叶及凋落叶,研究其水溶性组分(water soluble component,WSC)、有机溶性组分(organic...     

Analysis of long-term changes in the dates of seasonal phenomena in plants and insects of the Il’men Reserve as related to climatic factors

The results of monitoring the dates of the onset of flowering and leaf budding in eight herbaceous and woody plant species and the first appearance of three insect species in the Il’men Reserve (1972–2005) were processed by means of regression and correlation analyses. No significant changes in test parameters were revealed in the majority of these species. Only two early spring plants, coltsfoot (Tussilago farfara L.) and goat willow (Salix caprea L.), showed a weak tendency toward earlier flowering in the 1980s and 1990s. This is explained primarily by the absence of any significant trends in spring and summer air temperatures in the study region over the observation period. On the other hand, interannual fluctuations in the dates of plant flowering and insect appearance were well manifested not only in early spring but also in late-spring species. These fluctuations proved to depend largely on spring temperatures: in years with early and warm springs, flowering and leaf budding in plants and the appearance of first individuals in insects were recorded on significantly earlier dates.     

垂直面绿化植物遮阳系数与叶面积指数研究

比较、分析了农业研究中提出的叶面积指数LAI与用于建筑节能领域的垂直面绿化植物叶片遮阳系数SCPVW两个概念的异同和各自的应用范围。指出城市绿化采用水平或垂直绿化方式时,由于下垫面差异,植物叶片的遮阳系数应当分别采用LAI和SCPVW进行计算。     

Application of 1D and 2D MFR reactor technology for the isolation of insecticidal and anti-microbial properties from pyrolysis bio-oils

Valuable chemicals can be separated from agricultural residues by chemical or thermochemical processes. The application of pyrolysis has already been demonstrated as an efficient means to produce a liquid with a high concentration of desired product. The objective of this study was to apply an insect and microorganism bioassay-guided approach to separate and isolate pesticidal compounds from bio-oil produced through biomass pyrolysis. Tobacco leaf (Nicotianata bacum), tomato plant (Solanum lycopersicum), and spent coffee (Coffea arabica) grounds were pyrolyzed at 10°C/min from ambient to 565°C using the mechanically fluidized reactor (MFR). With one-dimensional (1D) MFR pyrolysis, the composition of the product vapors varied as the reactor temperature was raised allowing for the selection of the temperature range that corresponds to vapors with a high concentration of pesticidal properties. Further product separation was performed in a fractional condensation train, or 2D MFR pyrolysis, thus allowing for the separation of vapor components according to their condensation temperature. The 300–400°C tobacco and tomato bio-oil cuts from the 1D MFR showed the highest insecticidal and anti-microbial activity compared to the other bio-oil cuts. The 300–350 and 350–400°C bio-oil cuts produced by 2D MFR had the highest insecticidal activity when the bio-oil was collected from the 210°C condenser. The tobacco and tomato bio-oil had similar insecticidal activity (LC₅₀ of 2.1 and 2.2 mg/mL) when the bio-oil was collected in the 210°C condenser from the 300–350°C reactor temperature gases. The 2D MFR does concentrate the pesticidal products compared to the 1D MFR and thus can reduce the need for further separation steps such as solvent extraction.     

表面活性剂对叶面滞尘作用的影响

表面活性剂能够增强植物叶面滞尘能力,研究不同表面活性剂对植物滞尘能力的影响,对于利用植物防治粉尘污染有重要意义。以LAS、DTAB、AR和APG200为喷洒试剂,研究了8种植物吸附表面活性剂后滞留粉尘的重量、组分。结果表明,LAS浓度、植物种类、表面活性剂类型对滞尘量和面积比具有显著影响(P<0.05);表面活性剂能够有效提高植物滞尘能力,LAS、DTAB效果优于生物型AR、APG200,且测试叶面滞尘量的变化与叶面接触角无明显关系;LAS使除朴树外所有植物的滞尘能力增加的浓度为0.2 g/L,而对滞留粉尘组分改变较大的浓度为0.5 g/L;此外,表面活性剂能改变滞留粉尘的组分,但不具有明显的规律性,粉尘的遮光比变化趋势与叶面滞尘量基本相似。     

Visible leaf injury in young trees of Fagus sylvatica L. and Quercus robur L. in relation to ozone uptake and ozone exposure. An Open-Top Chambers experiment in South Alpine environmental conditions

An Open-Top Chambers experiment on Fagus sylvatica and Quercus robur seedlings was conducted in order to compare the performance of an exposure-based (AOT40) and a flux-based approaches in predicting the appearance of ozone visible injuries on leaves. Three different ozone treatments (charcoal-filtered; non-filtered; and open plots) and two soil moisture treatments (watered and non-watered plots) were performed. A Jarvisian stomatal conductance model was drawn up and parameterised for both species and typical South Alpine environmental conditions, thus allowing the calculation of ozone stomatal fluxes for every treatment. A critical ozone flux level for the onset of leaf visible injury in beech was clearly identified between 32.6 and 33.6 mmolO3 m(-2). In contrast, it was not possible to identify an exposure critical level using the AOT40 index. Water stress delayed the onset of the leaf visible injuries, but the flux-based approach was able to take it into account accurately.     

镉胁迫对苎麻(Boehmeria nivea)根系及叶片抗氧化系统的影响

镉(Cd)是非必需和毒性最强的重金属元素之一,不合理的开发利用可导致土壤受到Cd的严重污染,严重危及土壤环境或水环境。以苎麻为材料,采用模拟镉(Cd)污染盆栽培养法,选择21 d和49 d等2个不同胁迫期,测定不同浓度Cd2+胁迫下苎麻根系与叶片中渗透调节物质含量、超氧化物岐化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、丙二醛(MDA)含量及根系活力的变化。结果表明,高浓度胁迫49 d后,苎麻根系中的渗透调节物质含量明显高于叶片含量,且极显著高于对照,并在240 mg·L~(-1)Cd处理下出现最高值;胁迫49 d时,根系与叶片的渗透调节物质含量与Cd2+浓度极显著正相关。在2个不同胁迫周期,苎麻根系的SOD与POD活性均明显高于叶片;在胁迫21 d时,根系的CAT活性低于叶片,而胁迫49 d后,则明显高于叶片;胁迫21 d时,苎麻根系与叶片的抗氧化酶活性均较胁迫49 d要高;胁迫49 d时,根系POD活性与Cd2+浓度呈极显著正相关,表明根系POD酶在抗氧化酶中占主导地位。不同胁迫时长下苎麻根系或叶片的MDA含量变化趋势不明显,但根系或叶片受胁迫21 d后的MDA含量随Cd2+浓度增加的波动相对受胁迫49 d后的更明显,表明植物早期生理功能出现暂时性的修复。2个不同胁迫周期内,不同浓度镉胁迫下苎麻的根系活力均比对照组下降。研究显示,苎麻根系与叶片对镉胁迫的应答机制不同,且在不同胁迫时间下的响应机理差异较大,根系表现出更强的耐受能力。     

郑州市土壤与绿色植物中汞的分布特征

汞污染具有生物积累性,因而得到社会广泛关注。研究监测和评估了郑州市城区土壤和绿色植物叶片中汞浓度、分布、污染水平等。研究发现郑州市主城区土壤总汞浓度为0. 150～0. 958 mg/kg,平均浓度为0. 448 mg/kg;郑州市主城区绿色植物叶片总汞浓度为0. 017～0. 249 mg/kg,平均浓度为0. 107 mg/kg;土壤和叶片中汞浓度按功能区排序为交通枢纽区工业区商业区行政区高教区住宅区。采用地累积指数法对郑州市80个土壤样品的汞污染水平进行评估,结果显示60%受到轻度污染,35%受到偏中度污染,5%受到中度污染。研究较为全面地分析了土壤汞污染的现状及浓度,为郑州市土壤汞污染防治提供参考。     

Trait space of rare plants in a fire‐dependent ecosystem

The causes of species rarity are of critical concern because of the high extinction risk associated with rarity. Studies examining individual rare species have limited generality, whereas trait‐based approaches offer a means to identify functional causes of rarity that can be applied to communities with disparate species pools. Differences in functional traits between rare and common species may be indicative of the functional causes of species rarity and may therefore be useful in crafting species conservation strategies. However, there is a conspicuous lack of studies comparing the functional traits of rare species and co‐occurring common species. We measured 18 important functional traits for 19 rare and 134 common understory plant species from North Carolina's Sandhills region and compared their trait distributions to determine whether there are significant functional differences that may explain species rarity. Flowering, fire, and tissue‐chemistry traits differed significantly between rare and common, co‐occurring species. Differences in specific traits suggest that fire suppression has driven rarity in this system and that changes to the timing and severity of prescribed fire may improve conservation success. Our method provides a useful tool to prioritize conservation efforts in other systems based on the likelihood that rare species are functionally capable of persisting.     

城市街道常绿灌木植物叶片滞尘能力及滞尘颗粒物形态

城市园林植被中街道常绿灌木受工业排放、机动车尾气和道路扬尘等多重污染影响,其叶片生长高度恰好接近人体呼吸带,叶片受污染程度可反映人体污染暴露水平,是良好的环境质量代用指标。对于北方城市环境而言,常绿植被叶片的滞尘效应尤其重要。作者选择大气颗粒物污染严重的石家庄市为代表,对北方地区园林常用灌木植物大叶黄杨叶片的滞尘效应进行了研究。在石市4条主交通干道两旁样点首先对选定的大叶黄杨叶片进行冲洗,5日后取回载尘叶片进行滞尘量测量,重复进行5次,获得5个周期内叶片滞尘量数据;并对叶片表面滞尘颗粒物形态进行扫描电镜观察。结果表明,晴朗微风天气条件下,大叶黄杨叶片平均滞尘量为0.8614g·m-2·d-1,单叶最大饱和滞尘量为11.6197g·m-2,累积达到叶片饱和滞尘量的时间是15日。大叶黄杨叶片滞尘量大于同时期环境监测的大气降尘量,差额来自机动车排放和道路扬尘影响,这种影响约占叶片全部滞尘量的34.7%。大叶黄杨叶片表面滞尘为粒径小于10μm的颗粒物,深度清洗后叶片表面仍滞留粒径小于5μm的颗粒物,说明大叶黄杨叶片可以固定有害悬浮颗粒物并使之从大气环境中清除。本研究表明大叶黄杨强滞尘能力是城市近地面层环境中清除颗粒物污染的重要机制。