利用部分生理生化指标监测SO2对农作物急性伤害的研究

利用田间开顶式熏气装置对盆栽小麦和几种蔬菜作物进行熏气试验,研究相同SO2熏气浓度不同熏气时间供试样本叶液pH值、叶片电导率、含硫量的变化,结果表明在SO2熏气时间和叶液pH值之间存在显著线性负相关性,SO2熏气时间和叶片含硫量、叶片电导率之间存在显著线性正相关性.在叶片含硫量、叶片电导率和叶液pH值三个参数中,叶片含硫量是监测SO2对农作物急性伤害最为敏感的指标.然后利用相同的田间开项式熏气装置选择三个品种的水稻进行不同浓度相同时间的田间熏气试验,分析叶片含硫量的变化规律.研究表明,在同一生育期内,随着SO2熏气浓度的增大,三个水稻品种叶片中硫的含量呈明显增加趋势,且不同SO2浓度处理的水稻叶片含硫量和对照比较均有提高且差异显著.     

二氧化硫胁迫对园林植物幼苗生理生态特征的影响

为探讨28种广州市常用园林植物抗SO2污染能力,以2～3a生实生苗为材料,通过人工气候室的盆栽实验,测定了5.329mg/m3SO2浓度胁迫处理下其叶片气体交换参数、相对叶绿素含量和相对含水量生理生态指标,并利用隶属函数法及系统聚类分析法对其抗SO2污染能力进行了综合评价。结果表明:与相对清洁区相比,SO2污染胁迫下大多数植物叶片净光合速率、蒸腾速率、气孔导度、相对叶绿素含量和相对含水量均出现不同程度的下降,下降幅度因植物种类的不同而有较大的差异。综合隶属函数和聚类分析表明,桂花、夹竹桃、小叶榄仁、罗汉松、樟树、乐昌含笑、石栗、糖胶树、竹柏和铁冬青抗SO2污染能力强,黄金榕、海南红豆、红千层、澳洲鸭脚木、幌伞枫抗SO2污染能力较强,洋紫荆、菩提榕、长芒杜英、非洲桃花心和大花五桠果抗SO2污染能力中等,红花银桦、海南蒲桃、木棉、大花紫薇和人面子抗SO2污染能力较弱,而白千层、麻楝和复羽叶栾树抗SO2污染能力弱。研究结果可为火电厂、陶瓷厂、钢铁厂、石化厂等重度酸污染地区植物选择提供参考。     

通州区东郊森林公园不同树种叶片滞尘能力探究

植物叶片对粉尘有明显的阻挡、过滤和吸附作用,可使大气含尘量降低,探讨不同植物的滞尘能力具有重要的意义。以通州区东郊森林公园的3种杨树和8种典型园林绿化树种为研究对象,运用方格法计算叶面积、质量差减法计算其滞尘量,对不同树种的滞尘能力进行的分析评价结果表明:同一采样周期,3种杨树在林缘处采集的叶片滞尘量均远远大于林内的叶片;3种杨树中,新疆杨的林内叶片滞尘量和林缘叶片滞尘量总体上远大于河北杨与小叶杨;在同一采样点,3种杨树叶片的滞尘量随时间变化却并不相同;8种园林绿化树种的滞尘能力存在相当大的差异,灌木树种以金叶女贞最小、玫瑰最大,乔木树种以垂柳最小、洋白蜡最大,灌木树种的滞尘能力总体远高于乔木树种,约为乔木树种的3.1倍。     

六种乡土树种重金属富集特性试验研究

有针对性地选取广东地区常见的六种绿化乡土树种进行重金属富集特性试验研究。在轻度污染的Cd-Pb-Cu土壤上,六种植物生物量均未显著下降。植物重金属富集系数与土壤重金属质量分数相关,与植株生物量没有显著相关关系。香樟、小叶榕、构树、人面子的根部Cd的富集系数大于1,石斑木地上部及根部Cd的富集系数均大于1;香樟、小叶榕、构树的根部Pb的富集系数大于1;小叶榕的根部Cu的富集系数大于1。六种植物对重金属均有不同程度的富集能力,且表现为根部富集能力大于地上部,并非超富集植物。抗逆性强、根系发达、生物量大的乡土树种可作为修复城市低Cd-Pb-Cu复合污染场地的园林植物。     

水杨酸对灌木幼苗抗旱性的影响

在水分胁迫条件下,以紫丁香、小叶锦鸡儿和乌苏里绣线菊2年生苗木为材料,叶面喷施不同浓度水杨酸。试验发现,水杨酸(SA)能有效降低水分胁迫条件下各树种叶片MDA含量,延缓可溶性蛋白质和叶绿素含量的下降。对各处理进行了抗旱性综合鉴定,证明了水杨酸预处理在灌木树种抵御干旱方面作用明显。7.0×10-5mol/L的SA既能显著提高丁香、小叶锦鸡儿和乌苏里绣线菊的水分利用效率,又能显著提高它们的抗旱能力。     

典型森林树种对大气颗粒物湿沉降的影响

选择典型森林树种油松和侧柏作为研究对象,通过在2种树的冠层不同高度处(8,6,4,2m)布设湿沉降监测装置进行定位监测,比较单位叶面积滞尘量和降水对叶表面颗粒物冲刷率来分析2种树种对于大气颗粒物湿沉降的影响,并分析了树冠层不同高度颗粒物湿沉降以及不同粒径颗粒物湿沉降通量的变化规律,最后通过叶片显微结构来分析2种树种滞尘差异的原因。结果表明:(1)油松单位叶面积的滞尘量高于栓皮栎;降雨对2种树种叶面上大气颗粒物的冲刷率表现为栓皮栎高于油松。(2)油松枝下高2m处滞尘能力最强,大气颗粒物湿沉降通量最小;栓皮栎树冠中部4m处滞尘能力最强,且湿沉降通量最小。(3)油松冠层下部对于10~100μm污染物具有明显的截留作用,而栓皮栎的树冠上部对其具有更明显的截留作用。对于0.4~3μm和3~10μm颗粒物,油松的截留能力要强于栓皮栎。(4)油松和栓皮栎在叶表面显微结构的差异导致两者吸附颗粒物能力不同,油松叶片具有更多的褶皱、开度和密度较高的气孔以及相对较深的沟槽使其具有更强的吸附颗粒物的能力。     

陕西省关中地区城市绿化灌木的景观与生态服务功能调查分析

[目的]以景观服务和生态服务功能相结合的综合评价筛选树种,为城市绿化树种选择提供科学指导。[方法]通过对树种的景观服务功能(绿量、绿叶期、美观度)和生态服务功能(涵养水分、滞尘、造氧固碳、降温增湿、降噪)2个方面选取的10个指标的调查与测定,运用主成分分析法构建灌木树种的综合评价模型,对陕西关中地区城市常见26种绿化灌木进行评价。[结果](1)根据景观服务功能综合评价排序结果,小叶女贞(Ligustrum quihoui)、法国冬青(Viburnum odoratissinum)、红叶石楠(Photinia fraseri)、贴梗海棠(Chaenomeles speciosa)、大叶黄杨(Buxus megistophylla)、海桐(Pittosporum tobira)和雀舌黄杨(Buxus bodinieri)的综合评价分值最高(0.63～1.96),在美化、造景等方面是优选树种。(2)根据生态服务功能综合评价排序结果,小叶女贞、法国冬青、贴梗海棠、红叶石楠、海桐、火棘(Pyracantha fortuneana)的评价分值最高(0.7～3.04),在改善生态方面能力较为突出。(...     

栽培基质对小叶榕块根生长的影响

应用正交设计的方法,研究了不同栽培基质对小叶榕(6个月苗龄)块根生长的影响,结果表明,不同栽培基质对小叶榕块根的生长影响差异显著.经过6个多月的种植试验, 6份沙子+2份椰糠+3份草炭+1份豆粕为栽培基质的小叶榕在块根生长上明显高于其他处理.     

榕属植物在广州市园林应用的问题及其对策

桑科(Moraceae)榕属(Ficus)植物在我国有着悠久的栽培应用历史,特别是在我国南方,被广泛地栽植并应用于园林绿化建设,可以说是最普遍的一类绿化树种。然而,正是因为榕树的普遍性和传统性,往往使人忽视其生物特性而盲目扩大种植,榕属植物在绿化应用中的问题和矛盾也逐渐突显出来。通过对广州市常用榕属植物——小叶榕、黄葛榕、高山榕的应用情况调查,发现其在绿化配置中存在的种种问题,并提出对策。     

城市植被净化大气价值计量与评价——以西安市为例

对西安市植被净化大气物质量及价值测定结果表明 ,植被净化大气年总价值为 34 2 6 35 6亿元 ,占 1999年西安市国内生产总值的 6 % ,其中年固定CO2 和释放O2 的价值为 2 7 1830 9亿元 ,年吸收SO2 、HF和NOX3种污染物的价值为 1 82 896亿元 ,年滞尘价值为 1 82 5 11亿元 ,年灭菌价值为 3 4 2 6 4 0亿元。并通过MapInfo的叠加分析得出各行政区统计结果。     

钾在植物抗病性中的作用及机理的研究进展

本文对近些年来有关钾营养与植物病害关系的研究进行综述。主要从钾对酚代谢、碳、氮代谢及其活性氧代谢调控的角度,评述钾素营养提高植物抗病性的机理;同时讨论了钾肥的施用方式、钾肥形态、施用量、土壤本身钾素状况等共同影响钾素对植物的抗病性及其可能机理。最后提出这一研究领域存在的若干问题。     

控失尿素和密植对辽河三角洲水稻产量和氮素利用率的影响

为了明确氮肥类型和种植密度对辽河三角洲水稻产量和氮素利用的影响,选择典型稻田,以不施肥+稀植和不施肥+密植为对照,在氮肥施用量相同的基础上,设置了普通尿素+稀植、普通尿素+密植、控失尿素+稀植、控失尿素+密植处理,分析了不同处理方式下的水稻生长、产量和氮素利用率的差异.结果 表明:水稻产量和氮素利用率受到氮肥类型的显著...     

Cholesterol-lowering effects of plant steryl and stanyl laurate by oral administration in mice

The present study was conducted to investigate the efficacy of synthesized plant steryl and stanyl laurate in lowering the cholesterol level and to further examine the cholesterol-lowering potential of the free plant sterols and stanols dissolved in liquid emulsion on serum and liver lipids in mice by oral administration. Experimental results showed that both plant steryl and stanyl laurate could significantly decrease the serum levels of TC, LDL-C, LDL-C/HDL-C, and liver cholesterol contents and markedly increase fecal cholesterol concentrations but have no effect on serum TAG level, indicating that the produced plant steryl and stanyl laurate retained the cholesterol-lowering potential of natural plant sterols and stanols. However, no statistical difference in cholesterol-lowering efficacy was observed between plant steryl laurate and plant stanyl laurate, and free plant sterols and stanols dissolved in liquid emulsion could also significantly decrease serum cholesterol levels and markedly increase fecal cholesterol excretion. These results suggested that the esterified plant sterols/stanols had comparable effects to the free plant sterols/stanols in lowering serum TC levels but that they did gain a solubility advantage from the free plant sterols/stanols. Therefore, plant steryl/stanyl laurate could be considered as a potential nutraceutical or functional ingredient to reduce or prevent atherosclerosis and its related complications.     

Earthworms enhance plant regrowth in a grassland plant diversity gradient

Knowledge of the role of decomposers in the plant diversity–productivity relationship is scarce. In the framework of the Jena Experiment, we observed regrowth of grassland plant communities varying in plant species and functional group richness three weeks after mowing. We investigated earthworm subplots and subplots with reduced earthworm density in order to explore if earthworms enhance plant regrowth and if earthworm effects depend on plant diversity. Earthworms significantly enhanced each of the plant regrowth parameters (plant coverage and maximum and average height of the vegetation) suggesting that particularly fast growing species, such as grasses, benefit from earthworm activity. However, the average height of the vegetation was not affected in 16-species mixtures suggesting compensation of the impact of earthworms on plant regrowth in complex plant communities.     

Rapid effects of plant species diversity and identity on soil microbial communities in experimental grassland ecosystems

Changes in plant community structure, including the loss of plant diversity may affect soil microbial communities. To test this hypothesis, plant diversity and composition were experimentally varied in grassland plots cultivated with monocultures or mixtures of 2, 3 or 4 species. We tested the effects of monocultures versus mixtures and of plant species composition on culturable soil bacterial activity, number of substrates used and catabolic diversity, microbial biomass N, microbial respiration, and root biomass. These properties were all measured 10 months after seeding the experiment. Soil bacterial activity, number of substrates used and catabolic diversity were measured in the different plant communities using BIOLOG GN and GP microplates, which are redox-based tests measuring capacity of soil culturable bacteria to use a variety of organic substrates. Microbial biomass N, microbial respiration, and root biomass were insensitive to plant diversity. Culturable soil microbial activity, substrates used and diversity declined with declining plant diversity. Their activity, number of substrates used and diversity were significantly higher in plots with 3 and 4 plant species than in monocultures and in plots with 2 species. There was also an effect of plant species composition. Culturable soil microbial activity and diversity was higher in the four-species plant community than in any of the plant monocultures suggesting that the effect of plant diversity could not be explained by the presence of a particular plant species. Our results showed that changes in plant diversity and composition in grassland ecosystems lead to a rapid response of bacterial activity and diversity.     

红河干热河谷2年生吉贝人工幼林施肥效应研究

为明确吉贝幼林施肥配比及施肥量,采用单因素及N,P,K三因素L9(34)正交设计法,研究了施肥对2a生吉贝造林成活率及生长促进的影响。结果表明:(1)施基肥导致吉贝造林平均成活率下降6.92%以上,尿素200g/株处理与CK0差异显著;(2)施用复合肥400g/株、尿素300g/株处理树高、地茎增量与CK1差异显著,100g/株N+100g/株P+50g/株K、200g/株N+100g/株P+150g/株K组合树高、地茎、冠幅与CK1差异极显著,分枝数与CK1差异显著,除300g/株N+200g/株P+150g/株K组合增效指数小于尿素300g/株处理外,其余组合增效指数大于复合肥400g/株、尿素300g/株处理;(3)极差R比较认为,P肥对树高生长显著,N肥对地茎和冠幅生长较好,而分枝数第1年施K肥较P肥、N肥好,第2年施P肥较K肥、N肥好;(4)N,P,K组合较单因素肥效显著,肥效指数大小可作为吉贝幼林施肥生长快慢的衡量指标。可见,干热河谷吉贝造林以不施基肥为宜,尤其不能施尿素,幼林追肥经济效益显著,1～2a生林可采用100g/株N+100g/株P+100g/株K或200g/株N+100g/株P+150g/株K肥料组合以及复合肥400g/株、尿素300g/株单施。     

沙地植物生长对CO2增加和土壤干旱的响应

实验研究了毛乌素沙地优势植物种柠条、杨柴、油蒿的根长、主茎高、地径等生长量对大气中CO2浓度增加和土壤干旱的响应。结果表明:大气中CO2浓度增加和土壤干旱对植物生长量的影响是十分复杂的,不仅不同的植物种对CO2浓度的反应不同,而且不同的植物对土壤干旱的反应也有差异,由此而使得大气中CO2浓度增加和土壤干旱对植物的复合影响十分复杂。     

Plant community impacts on the structure of earthworm communities depend on season and change with time

Declining plant diversity potentially threatens essential ecosystem functions driven by the decomposer community, such as litter decomposition and nutrient cycling. Currently, there is no consensus on the interrelationships between plant diversity and decomposer performance and previous studies highlighted the urgent need for long-term experiments.In the Jena Experiment we investigated the long-term impacts of plant community characteristics on the structure of earthworm communities representing key decomposers in temperate grassland. We repeatedly sampled plots varying in plant species richness (1-16 species), plant functional group richness (1-4 groups), and presence of certain plant functional groups (grasses and legumes) three, four, and six years after establishment of the experiment in spring and autumn.The results show that earthworm performance is essentially driven by the presence of certain plant functional groups via a variety of mechanisms. Plant productivity (root biomass) explained most of the detrimental grass impacts (decrease in earthworm performance), while beneficial legume effects likely were linked to high quality inputs of plant residues (increase in earthworm performance). These impacts depended on the functional group of earthworms with the strongest effects on surface feeding anecic earthworms and minor effects on soil feeding endogeic species. Remarkably, effects of plant community characteristics on the composition and age structure of earthworm communities varied between seasons. Moreover, plant diversity effects reported by a former study decreased and detrimental effects of grasses increased with time.The results indicate that plant community characteristics, such as declining diversity, indeed affect the structure of earthworm communities; however, loss of key plant functional groups is likely to be more important than plant species number per se. However, in frequently disturbed ecosystems plant species richness might be important for the recovery and resilience of belowground functions. Moreover, the results accentuate the importance of long-term repeated measurements to fully appreciate the impacts of plant community composition and diversity on ecosystem properties. Single point observations may be misleading and potentially mask the complexity of above-belowground interrelationships.     

山地自然保护区垂直带植物铅含量特征

Typical plants and soils of four elevation zones, mountain tundra （Zone A）, Betula ermanii forest （Zone B）, mountain dark coniferous forest （Zone C）, and mountain coniferous and broad-leaf forest （Zone D）, along the vertical gradient of the northern mountain slope of the Changbai Mountain National Nature Reserve, Jilin Province, China, were sampled to study the relationship between plant and soil Pb, and to compare the Pb levels in typical plant types within the same elevation zone. The Pb contents in the soil and plant samples were measured by using a flame atomic absorption spectrophotometer. The results showed that the average plant Pb contents of the four plant elevation zones were lower than the average worldwide level, except for Zone B. Compared with the average level in China or the average worldwide level, the soil Pb levels of the four plant zones were higher, with Zones D and B having the lowest and highest averages, respectively. Plant Pb levels fluctuated from the upper to the lower zones, in a pattern of low-high-low-high, which was the same as that of the soils in the four zones. Furthermore, plant Pb was closely related to soil Pb. Depending on the plant species and plant parts, large differences were found in the Pb levels of typical plants within each zone. In Zone A, Vaccinium uliginosum and Rhododendron redowskianum had higher Pb levels than the other plants. In Zone C, the Pb levels in the branches of both plant species were higher than those in the leaves, which was contrary to Zone D. In Zone B, the Pb levels in the plant parts varied greatly with plant species.     

Effects of six grassland plant species on soil nematodes: A glasshouse experiment

The effects of six individual plant species on the abundance and composition of nematode communities were studied in a glasshouse experiment during 16 weeks. The effect of the presence of plants, the correlation between nematode abundance and plant biomass, the response of plant-feeding nematodes and other nematode groups to different plant species was examined and also whether the effect differed between plant species within a plant functional group. The total number of nematodes increased during the study period in all treatments, although in some treatments, the increase levelled off after 8 or 12 weeks. The identity of the plant species affected both the total abundance of nematodes and the nematode community composition. The number of bacterial-feeding nematodes was greatest under grasses and legumes and was positively correlated with shoot biomass and negatively with root biomass. The response of the plant-feeding nematodes, which differed in abundance under both the investigated legume and the forb species, suggests that the identity of the plant species is more important than the plant functional group. A possible explanation could be related to differences in plant secondary metabolites. Despite some differences in the nematode species pool, the effects of plant species appear quite consistent between the present glasshouse study and previous field experiments.