城市绿化树种的选择与配置——以兰州市西固工业区为例

本文以地处中国西北干旱区的兰州市西固工业区为例，考察了该区绿化历史和现状，在此基础上，指出城市绿化树种的选择必须符合当地自然地理特征、城市发展状况、环境污染特征的原则，树种的配置应充分考虑绿化效益的发挥，同时兼顾经济可行性，并对兰州市西固工业区绿化提出了针对性的建议。     

大气中氟化物和二氧化硫对连云港市郊果树、蔬菜的影响

通过植物监测,对连云港市郊局部地区果树、蔬菜等连年来品质产量下降的原因进行研究。结果发现大气中氟化物(HF)含量高,局部以化工为主的地区污染较为突出,已对果树、蔬菜造成直接危害。此外,二氧化硫(SO_2)及其复合污染也存在一定影响。     

Prenatal diagnosis of familial ring 21 chromosome

Ring chromosome 21 is a rare chromosome anomaly often associated with mental retardation and dysmorphic features. Less commonly, the ring chromosome can be familial and associated with a normal phenotype. Phenotypically normal female carriers, however, are at increased risk of having children with Down syndrome, mosaic monosomy 21, and variable duplication or deletion of chromosome 21. Because of the relative mitotic and meiotic instability of ring chromosomes, abnormal cytogenetic findings encountered during prenatal diagnosis may not reflect the true genetic status of the fetus. This is a report of a phenotypically normal female carrier of a familial ring 21 chromosome. Prenatal diagnosis on her twin pregnancy revealed a mosaic 46,XX,r(21)(p13;q22) (77 per cent)/45,XX, – 21 in one fetus and a normal male karyotype in the second. The pregnancy was carried to term. Both infants are completely normal, with a non-mosaic ring 21 karyotype from the lymphocytes of one twin. The diagnostic uncertainty and problematic genetic counselling related to fetal cytogenetic abnormalities are the subjects of this report.     

南京市主要绿化树种对大气固体悬浮物净化能力及规律研究

对南京市不同功能绿地类型的26种主要绿化树种净化大气固体悬浮物的能力进行监测分析,研究不同功能区主要树种叶片滞尘量的季节变化,应用SAS软件,综合考虑单位面积滞尘量、单叶滞尘量、干重滞尘量3种指标对绿化树种滞尘能力进行聚类评估.结果表明,大部分绿化树种叶片滞尘量的季节变化为春季高、夏季降低、秋季增高、冬季达最高,这与空气中悬浮颗粒物含量季节变化的规律相一致;同一树种在不同地点的叶片滞尘量可以反映树木所在环境空气质量,灵谷寺公园和栖霞山空气质量优于梅山钢铁厂和宁镇公路;不同树木类型间滞尘能力差异较大,灌木滞尘量最大,常绿乔木其次,落叶乔木最小.     

衡阳市区主要园林树木害虫的种类与危害研究

在调查、采集和饲养的基础上,共鉴定出衡阳市主要园林树木害虫84种.并分析了衡阳市区主要园林树木害虫的发生危害特点,提出了相应的防治策略.     

林木根系衰老研究方法与机制

根系衰老研究方法主要有根窗直接观测和挖根取样间接观测。在整株水平上,树木同化碳的能力,碳在不同器官间的分配,尤其是在地上部分和地下部分间的分配比例,对根的萌生和衰老起着重要作用;地上部分的生长过程和健康状况也对根系的生长和寿命有很大影响;当树木的生长环境受到某种胁迫时,树木的抵抗力下降,容易招致病原菌的危害,造成根系衰老和死亡。在生态系统水平上,干旱洪涝、干扰等胁迫和树木一土壤间的养分循环都会引起树木生长环境的改变,对根系的衰老过程发生作用;季节变化使树木的地上部分和地下部分的生理活动处于不同的旺盛期,从而使碳的分配方式有些改变,影响到根系的生长;土壤中养分的存在形式,某些离子的浓度也直接影响到根的寿命;病原菌对根系的危害与土壤中养分含量变化有关。所以,衰老过程受环境条件的影响,伴随着代谢,RNA和蛋白质合成速率的下降和(或)膜与细胞器结构的改变。     

Leaf volatiles and polyphenols in pear trees infested byPsylla pyricola. Evidence of simultaneously induced responses

Summary Feeding by the homopteranPsylla pyricola on leaves of pear trees induces the production of volatile compounds, such as (E,E)--farnesene and methyl-salicylate, as well as the production of polyphenols. The inference on induction is based on GC-MS and HPLC chromatograms from the same samples ofPsylla infested leaves, leaves from the same pear tree beforePsylla infestation and uninfested leaves from other pear trees.Psylla infestation greatly enhanced the production of volatiles ((E,E)--farnesene, methyl-salicylate and others) and triggered the production of new polyphenols, characterized by much longer retention times.However, the responses to infestation depend critically on leaf age (defined by leaf distance to apex). With respect to the leaf volatiles it appears that infested, old leaves produce fewer compounds and lower amounts of the volatiles than infested, young leaves. Moreover, there seem to be differences in pattern. Relative to (E,E)--farnesene, methyl-salicylate was found in much lower amounts in heavily infested, old leaves. With respect to polyphenols it was found that infested old leaves collected in August have polyphenols with the same retention times, but more or less equal amounts as uninfested young leaves collected in May. This shows thatPsylla infestation causes the induced response mostly in young leaves.The induced leaf volatiles may act as synomones to heteropteran bugs. As shown elsewhere,Anthocoris nemoralis responds significantly to (E,E)--farnesene and methyl-salicylate when offered in pure form against clean air in a Y-tube olfactometer. The effect of polyphenols on the performance ofP. pyricola is not yet known. Hence, a role in direct defence is still to be investigated.     

模糊概率事件的故障树分析

许多职业事故的基本致因事件多属于模糊事件,其概率很难确定。本文以煤矿典型危害——内因火灾为例,探讨了模糊概率下的故障树分析问题。煤矿内因火灾故障树虽具有确定的结构形式,其基本致因事件的概率却无法统计。经过长期的生产实践,煤矿中一大批防火专家可以用自然语言较准确地描述基本事件发生的可能性,这就为故障树分析提供了有效信息。文中以模糊数学为基础,引入Delphi方法,征集并整理了25位专家对龙凤矿内因火灾致因的意见,确定了基本事件的模糊概率及其临界重要度排序,提出了行之有效的防治内因火灾措施。     

大型游乐设施风险评估与分级方法研究

大型游乐设施的运行是一个动态管理过程,不仅涉及设备本身,而且与人、环境等因素密切相关。针对这个特点,提出大型游乐设施风险矩阵(RMM)的风险分级方法。提出了将事故树与模糊数学相结合的模糊事故树法(FFTA);采用3σ模糊表征法计算大型游乐设施各类风险事故的概率;再采用信息熵法来评价大型游乐设施的风险后果;最后利用风险矩阵法来确定大型游乐设施的风险等级,并通过实例验证了该分级模型有效。     

基于决策树的黑龙江省旱耕地分类

基于决策树和EOS/MODIS数据,参考黑龙江省的农事活动和农作物发育期数据,对该省旱耕地进行了分类。结果表明,利用MODIS较高时间分辨率的特点,提取该省植被物候信息,可以在较短时间内实现对旱耕地分布及面积的定量描述;由于黑龙江省的干湿冷暖差异较大,按气候特征分区进行旱耕地判识的效果较好,总体精度可达到85.27%,Kappa系数0.8415。该项研究可为黑龙江省旱耕地面积数据的及时获取提供参考。