天津市植被异戊二烯排放量及时空分布特征

基于本地化改进的GLOBEIS模型,运用遥感图像解译的土地利用类型数据以及实际观测的小时气象数据,对天津市2013年植被异戊二烯排放总量进行估算和时空分布特征分析。研究表明,2013年天津市植被异戊二烯排放总量达到693.43 t(以C计,下同),排放强度为0.06 t·km~(-2)·a~(-1)。植被异戊二烯的排放具有明显的日变化、月变化和季节变化特征:中午高,夜间低;8月最高,1月最低;夏季排放量最大,冬季排放量最小。其空间特征与土地利用类型密切相关,植被异戊二烯的排放主要集中在林区较为密集的区域,并且在市内6区和滨海新区排放量较小。最后,对植被异戊二烯排放估算过程中的不确定性来源进行分析。     

“第九届世界竹子大会”优秀论文摘要

竹子的生物源挥发性有机化合物排放量:跨树种多样性模式探索Andrea N.Melnychenko,ToddN.Rosenstiel(波特兰州立大学生物系)摘要:植物叶片生物源挥发性有机化合物的排放量在生物化学和大气过程中起到了很重要     

环境空气中挥发性有机物（VOCs）来源解析的研究进展

基于国内外关于大气中挥发性有机物（VOCs）排放源研究的调查，阐述了环境空气中VOCs排放源以及来源解析的研究现状。研究结果表明：天然源最重要的排放物是异戊二烯和单萜烯；交通运输是全球最大的VOCs人为排放源，溶剂使用是第二大排放源；通过交通干道研究、隧道研究、实验室转鼓和台架实验研究，掌握了机动车不同车型尾气的VOCs组成特征；运用cMB和PMF模型得出VOCs的主要排放源有机动车尾气、燃料挥发（LPG、NG和汽油）、石油化工和涂料／溶剂的使用等，为进一步开展VOCs源解析研究提供参考。     

竹子的生物源挥发性有机化合物排放量:跨树种多样性模式探索

植物叶片生物源挥发性有机化合物的排放量在生物化学和大气过程中起到了很重要的作用。生物源挥发性有机化合物的排放量可能涉及数量不同多种化合物,是一种重要的植物信号传导方法。然而,一些挥发性化合物的排放量可能对区域内的空气质量产生负面的影响。为了更好的了解生物源挥发性有机物在植物生理学和化学生态学中的作用,更好的预测这些排放量将如何改变空气质量,必须要了解这些不同的化合物之间的潜在的联系。过去,对不同植物的生物挥发量进行直接比较是很困难的,因为调查和测量往往集中于一类数量有限的化合物中,并且在对不同功能组别的化合物的分离和检测的分析技术也较为缺乏。此外,相关性强的树种通常会挥发出相类似的化合物,这是使植物本身和与其他植物发出的生物源挥发性有机化合物的排放量难以辨明的原因。     

两次污染源普查农业面源对水环境影响变化情况探究

指出了水污染防治是生态文明建设的重要方面,是打赢污染防治攻坚战的重要议题。农业污染面源对水体污染负荷较大,污染较为严重,总磷及总氮排放量分别占全国水体污染物排放量50%以上。通过对一污普和二污普数据进行分析,比较了2007年和2017年农业面源污染变化情况,并据此提出了相应的防控对策。以供参考。     

天津市植被排放挥发性有机物估算及时空分布

基于本地化改进的GLOBEIS模型,运用遥感图像解译的土地利用类型数据以及实际观测的小时气象数据,对天津市2013年植被排放VOCs进行了估算和时空分布特征分析。结果表明,天津市2013年植被排放VOCs总量为7 678.35t C,其中,异戊二烯的排放量为693.43t,占9.0%;单萜烯的排放量为2 877.80t,占37.5%;其他VOCs的排放量为4 107.12t,占53.5%。在时间分布上,植被VOCs的排放具有明显的日变化和月变化特征:中午高,夜间低;8月份最高,1月份最低。在空间分布上,其空间分布特征与土地利用类型密切相关,植被VOCs排放主要集中在林区较为密集的区域,在蓟县北部排放量较大,在滨海新区和市内6区排放量较小。最后,对植被VOCs排放估算过程中的不确定性来源进行了分析。     

唐山市大气污染排放清单及分布特征分析研究

为研究唐山市大气污染源排放特征,通过“自上而下”结合“自下而上”的方式充分获取了该市活动水平数据,使用排放因子计算法,结合卫星遥感监测,形成了2020年大气污染源排放清单。结果表明：2020年唐山市SO₂、NO_X、CO、VOCs、NH₃、PM₁₀、PM_2.5的排放量分别是8.64万t、17.97万t、747.29万t、12.08万t、7.75万t、18.76万t和9.00万t;工艺过程源是多种污染物的主要排放源,其中SO₂、NO_X、CO、VOCs、PM₁₀、PM_2.5污染物排放量分别占全社会排放量的77.07%、48.99%、95.86%、77.48%、44.60%、65.04%;扬尘源对PM₁₀污染物排放量贡献最大(贡献率48.46%);农业源对NH₃污染物排放量贡献最大(贡献率92.26%);排放量较大的区域集中在迁安市、滦州市、丰南区一带。     

植物精油在食品保鲜中的应用研究

食品保鲜是食品工业所面临的一大难题,为了防止食品腐败变质,延长食品货架期,常常在食品中添加保鲜剂。植物精油作为天然源保鲜剂的重要来源,是一种挥发性较好的保鲜剂,以直接接触或熏蒸的方式在食物周围形成抑菌氛围,从而达到防腐保鲜。主要阐述了植物精油的抑菌活性、抑菌机理及其在食品保鲜中的应用,为食品天然源保鲜剂的开发和应用提供参考。     

张家川多源互补热泵供暖系统运行分析

为提升张家川县张棉乡中学冬季供暖的热舒适性,对学校原锅炉房采取热源系统进行了改造。对改造后的多源互补热泵系统进行了介绍,并对系统的运行状况及各项数据进行了分析,结果表明:利用多源互补热泵系统不仅满足当地供暖需求,同时还弥补了单一热源系统所存在的不足。系统运行期间校宿舍室内平均温度为20.4℃,系统日平均耗电量为2614.32 kW·h。其中,空气源热泵机组平均COP为2.56,水源热泵机组平均COP为3.92。较原燃煤锅炉系统,供暖季减少NO_x排放量888 kg,SO_2排放量1020 kg,CO_2排放量314400 kg,属于清洁、环保、高效的供暖热源方案。     

模拟氮沉降对雌雄美洲黑杨光合特性和异戊二烯释放的影响

采用盆栽法研究了模拟氮沉降对美洲黑杨(Populus deltoides Bartr.)雌雄幼苗光合特性和异戊二烯释放的影响。试验设置了低氮、中氮、高氮和对照4个氮沉降梯度。结果表明:随着氮沉降浓度的升高,雌株的蒸腾速率、净光合速率、胞间二氧化碳浓度和气孔导度下降,异戊二烯释放浓度和排放速率升高;而雄株光合参数和异戊二烯释放浓度和排放速率变化不大。雌株叶片异戊二烯释放浓度和排放速率与净光合速率呈显著负相关,而雄株异戊二烯释放与光合生理参数相关系数均不显著。说明雌雄美洲黑杨幼苗的光合特征和异戊二烯释放对氮沉降存在差异性响应。     

Reduction of isoprene emissions from live oak (Quercus fusiformis) with oak wilt

Many plants emit isoprene, a hydrocarbon that has important influences on atmospheric chemistry. Pathogens may affect isoprene fluxes, both through damage to plant tissue and by changing the abundance of isoprene-emitting species. Live oaks (Quercus fusiformis (Small) Sarg. and Q. virginiana Mill) are major emitters of isoprene in the southern United States, and oak populations in Texas are being dramatically reduced by oak wilt, a widespread fungal vascular disease. We investigated the effects of oak wilt on isoprene emissions from live oak leaves (Q. fusiformis) in the field, as a first step in exploring the physiological effects of oak wilt on isoprene production and the implications of these effects for larger-scale isoprene fluxes. Isoprene emission rates per unit dry leaf mass were 44% lower for actively symptomatic leaves than for leaves on healthy trees (P = 0.033). Isoprene fluxes were significantly negatively correlated with rankings of disease activity in the host tree (fluxes in leaves on healthy trees > healthy leaves on survivor trees > healthy leaves on the same branch as symptomatic leaves > symptomatic leaves; isoprene per unit dry mass: Spearman's rho = -0.781, P = 0.001; isoprene per unit leaf area: Spearman's rho = -0.652, P = 0.008). Photosynthesis and stomatal conductance were reduced by 57 and 63%, respectively, in symptomatic relative to healthy leaves (P < 0.05); these reductions were proportionally greater than the reductions in isoprene emissions. Low isoprene emission rates in symptomatic leaves are most simply explained by physiological constraints on isoprene production, such as water stress as a result of xylem blockage, rather than direct effects of the oak wilt fungus on isoprene synthesis. The effects of oak wilt on leaf-level isoprene emission rates are probably less important for regional isoprene fluxes than the reduction in oak leaf area across landscapes.     

Nocturnal isoprene emission from mature trees and diurnal acceleration of isoprene oxidation rates near Quercus serrata Thunb. leaves

Quercus serrata Thunb. ex Murray is a widespread deciduous oak in China, the Korean Peninsula, and Japan, and a strong isoprene emitter. Establishing accurate inventories of this species and estimating net carbon budgets, including biogenic volatile organic compounds (BVOC), necessitates detailed evaluation of BVOC emission and oxidation characteristics. Emissions of isoprene, the most abundant BVOC, presumably contribute to atmospheric chemistry through the formation of photochemical oxidants and secondary organic aerosols. We built an isoprene flux monitoring system to simultaneously reveal characteristics of the flux and fate of isoprene at multiple locations in Q. serrata forests. We used proton transfer reaction mass spectrometry (PTR-MS) and an automated closed chamber to measure isoprene emissions from soil and leaves in a warm-temperate Q. serrata forest. We used a relaxed eddy accumulation system with PTR-MS to simultaneously measure the canopy flux. In continuous foliage chamber measurements, we observed daily variations of isoprene emissions and continuous nocturnal emissions from leaves. Nocturnal emissions exceeded 25 % of total daily leaf emissions and were relatively high at sunset and low at sunrise. These results suggest that nocturnal emissions from mature trees may not be negligible. When leaf emissions were high in the daytime, the canopy isoprene flux tended to plateau at an upper limit. Observations of isoprene concentrations and gradients suggest that the plateau was caused by acceleration of isoprene oxidation, and sequential formation of secondary organic aerosols may occur near the leaf just after emission. Elucidation of these linkages may require continuous field measurements with a simultaneous multi-flux monitoring system.     

Isoprene emission, photosynthesis, and growth in sweetgum (Liquidambar styraciflua) seedlings exposed to short- and long-term drying cycles

Isoprene emissions were studied in one-year old sweetgum (Liquidambar styraciflua L.) seedlings during nine drying-rewatering cycles extending over five months. Each drying cycle lasted to the point of leaf wilting. Growth was essentially stopped in response to the first drying cycle, though seedling survival and capacity to recover turgor on rewatering remained high throughout the entire nine cycles. Photosynthetic rates of leaves were inhibited by the drying treatments. Under severe drought, isoprene emission rates of leaves were also inhibited, though isoprene emission was generally less sensitive to drought than photosynthesis. The lower drought sensitivity of isoprene emission compared with photosynthesis resulted in a higher percentage of fixed carbon lost as isoprene as seedlings became more stressed. During the recovery phase of the drying-rewatering cycles, isoprene emission rates in several seedlings were higher than in well-watered control seedlings. Following the ninth drying-rewatering cycle, sustained daily watering resulted in recovery of isoprene emission rates to control values within four days. Photosynthetic rates only recovered to 50% of control values after seven days. We conclude that the mechanisms regulating photosynthetic rate and isoprene emission rate are differentially influenced by limited water supplies. The results are consistent with past studies that predict a protective role for isoprene emission during stress, particularly protection from excessive leaf temperatures during drought.     

Online analysis of volatile organic compound emissions from Sitka spruce (Picea sitchensis)

Volatile organic compound (VOC) emissions from Sitka spruce (Picea sitchensis Bong.) growing in a range of controlled light and temperature regimes were monitored online with a proton transfer reaction-mass spectrometer (PTR-MS) operating at a temporal resolution of approximately 1 min. Isoprene emissions accounted for an average of more than 70% of measured VOCs and up to 3.5% of assimilated carbon. Emission rates (E) for isoprene correlated closely with photosynthetic photon flux (PPF) and temperature, showing saturation at a PPF of between 300 and 400 micromol m(-2) s(-1) and a maximum between 35 and 38 degrees C. Under standard conditions of 30 degrees C and 1000 micromol m(-2) s(-1) PPF, the mean isoprene E was 13 microg gdm(-1) h(-1), considerably higher than previously observed in this species. Mean E for acetaldehyde, methanol and monoterpenes at 30 degrees C were 0.37, 0.78 and 2.97 microg gdm(-1) h(-1), respectively. In response to a sudden light to dark transition, isoprene E decreased exponentially by > 98% over about 3 h; however, during the first 7 min, this otherwise steady decay was temporarily but immediately depressed to approximately 40% of the pre-darkness rate, before rallying during the following 7 min to rejoin the general downward trajectory of the exponential decay. The sudden sharp fall in isoprene E was mirrored by a burst in acetaldehyde E. The acetaldehyde E maximum coincided with the isoprene E minimum (7 min post-illumination), and ceased when isoprene emissions resumed their exponential decay. The causes of, and linkages between, these phenomena were investigated.     

Seasonal parasitism of native egg parasitoids of brown marmorated stink bug (Halyomorpha halys) in Japan

Journal of Pest Science - The invasive, Halyomorpha halys (Hemiptera: Pentatomidae), is a severe economic insect pest native to East Asia. A strong effort has been made to identify natural egg...     

若尔盖辖曼自然保护区种子植物区系成分研究

经室内整理，辖曼自然保护区中的种子植物被鉴定为33科，106属，196种。按照属的分布区类型对这些种子植物研究，认为以温带植物区系为主。106个属中，世界广布属25个，北温带分布的属49个，旧世界温带分布的属11个，温带亚洲分布的属7个，东亚分布的属2个，泛热带分布的属2个，热带亚洲分布的属于1个，地中海区／西亚至东亚分布属5个，东亚和北美洲间断分布的属2个，中国特有属2个。     

天津大黄堡湿地生物多样性及保护利用

大黄堡湿地是由芦苇沼泽、鱼塘、水库及水渠等构成的复合型湿地类型,生物多样性十分丰富,尤其是水鸟种类多样。大黄堡湿地具有湿地生态系统的典型性与脆弱性、自然景观的独特性、生境类型的复杂性、生态系统演替的自然性和生态地位的特殊性等特点,是天津市唯一的具有良好湿地植被的天然湿地生态系统,同时也是东亚候鸟南北迁飞路线上一个停歇地和中转站。在分析大黄堡湿地生物多样性现状及保护中存在的主要问题的基础上,提出了相应的保护措施与发展策略。     

麦积山风景名胜区的珍稀濒危保护植物

麦积山风景名胜区有珍稀濒危保护植物19种，区系特点是以北温带成分为主，占该景区珍稀濒危植物总种数的40％，中国特有成分次之，占25％，东亚成分占20％，世界分布、热带亚洲至热带非洲分布、东亚和北美洲问断分布的成分各占5％。分析了景区珍稀濒危植物的现状及其应采取的保护措施。     

Kinetics of leaf temperature fluctuation affect isoprene emission from red oak (Quercus rubra) leaves

Because the rate of isoprene (2-methyl-1,3-butadiene) emission from plants is highly temperature-dependent, we investigated natural fluctuations in leaf temperature and effects of rapid temperature change on isoprene emission of red oak (Quercus rubra L.) leaves at the top of the canopy at Harvard Forest. Throughout the day, leaves often reached temperatures as much as 15 degrees C above air temperature. The highest temperatures were reached for only a few seconds at a time. We compared isoprene emission rates measured when leaf temperature was changed rapidly with those measured when temperature was changed slowly. In all cases, isoprene emission rate increased with increasing leaf temperature up to about 32 degrees C and then decreased with higher temperatures. The temperature at which isoprene emission rates began to decrease depended on how quickly measurements were made. Isoprene emission rates peaked at 32.5 degrees C when measured hourly, whereas rates peaked at 39 degrees C when measurements were made every four minutes. This behavior reflected the rapid increase in isoprene emission rate that occurred immediately after an increase in leaf temperature, and the subsequent decrease in isoprene emission rate when leaf temperature was held steady for longer than 20 minutes. We concluded that the observed temperature response of isoprene emission rate is a function of measurement protocol. Omitting this parameter from isoprene emission models will not affect simulated isoprene emission rates at mild temperatures, but can increase isoprene emission rates at high temperatures.     

Introduction of Mandshurian ash (Fraxinus mandshurica Rupr.) to Estonia: Is it related to the current epidemic on European ash (F. excelsior L.)?

Recent investigations in Japan have suggested that the causal organism of the ongoing epidemic affecting European ash (Fraxinus excelsior) in Europe, Hymenoscyphus pseudoalbidus, may originate in East Asia. The fungus may have been unintentionally carried to Europe during the introduction of Mandshurian ash (F. mandshurica), the host tree of the fungus in East Asia. Still unicentric emergence hypothesis is in force: An area in the eastern Poland or Baltic has been shown to be the presumed epicentre of the epidemic. Really, during the Soviet occupation, several consignments of F. mandshurica seeds and plants, originating directly from the natural range of F. mandshurica in East Asia (Russian Far East), reached Baltic areas. In this paper, an overview about the Mandshurian ash is presented, the history of introduction of F. mandshurica to Estonia is reviewed and colonization of F. excelsior in this country by H. pseudoalbidus is briefly discussed. At present, we could not find any evidence, spatial or temporal, for a direct connection of the disease emergence on native F. excelsior with the introduction of F. mandshurica. The pathogen first colonized northwest Estonia and moved southeast and not from south to north as would be expected according to the hitherto existing unicentric hypothesis. However, more information is needed from different regions before to pose a multicentric emergence hypothesis and to deepen more into the investigations of the environmental factors that affected the host and supported to the epidemic in different areas.