蒙古高原及其邻近地区的维管束植物区系分析初报(续)——Ⅱ.属的区系分析

内蒙古高原及其邻近地区有792属,其中蒙古与内蒙古共同的属为452属,相异的属为205属(只分布在蒙古的属有92属,在内蒙古的属有113属)。含有10个以上不同属的科是:菊科(28属),禾本科(18属),十字花科(17属),伞形科(12属),玄参科(11属),紫草科(10属),本区有10个大属,它们是:苔属(131种),黄芪属(94),棘豆属(90),蒿属(90),柳属(61)。风毛菊属(56),蓼厮(51),委陵菜属(46),马先蒿属(36),葱属(30),本区有3个特有属:四合木属,绵刺属和革苞菊属。     

植物表达抗体的研究进展

利用转基因植物生产抗体是一个新兴的生物技术领域。这种技术将编码全抗体或抗体片段的基因导入植物，从而在植物中产生全抗体或抗体片段，获得的抗体能功能性地识别抗原并结合抗原。目前已有农杆菌介导转移法和基因枪法等多种转化技术用于将抗体基因导入植物细胞。利用植物表达抗体的一大优势是能大规模廉价生产免疫治疗用抗体。此外，植物抗体也可用于植物自身抗病，并能调节植物细胞代谢。本文主要就植物生产抗体的方法、抗体的表达及应用作一综述。     

北京地区外来入侵植物的初步研究

经过调查和对大量文献资料的整理和分析,确定北京的外来入侵植物有91种,隶属25科,来源于世界各地的入侵植物有66种,其中 5种为有害检疫杂草,另有25种来源于国内其他地区.并对这些外来植物入侵北京后带来的影响和危害、入侵的途径以及应该采取的防治措施进行了讨论.     

Microstructural evolution and mechanical properties of an Fe–18Ni–16Cr–4Al base alloy during aging at 950℃

The development of Gen-IV nuclear systems and ultra-supercritical power plants proposes greater demands on structural materials used for key components. An Fe–18Ni–16Cr–4Al (316-base) alumina-forming austenitic steel was developed in our laboratory. Its microstructural evolution and mechanical properties during aging at 950℃ were investigated subsequently. Micro-structural changes were characterized by scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. Needle-shaped NiAl particles begin to precipitate in austenite after ageing for 10 h, whereas round NiAl particles in ferrite are coarsened during aging. Precipitates of NiAl with different shapes in different matrices result from differences in lattice misfits. The tensile plasticity increases by 32.4% after aging because of the improvement in the percentage of coincidence site lattice grain boundaries, whereas the tensile strength remains relatively high at approximately 790 MPa.     

四川长宁竹海国家级自然保护区种子植物区系分析

通过野外实地调查,对四川长宁竹海国家级自然保护区的种子植物区系进行了研究.结果表明:(1)该区共有种子植物140科692属1395种(含种下分类单位),其中裸子植物5科8属11种,被子植物135科684属1384种(其中双子叶植物116科543属1117种,单子叶植物19科141属267种);该区种子植物的科、属优势现象明显,以禾本科(Gramineae)、菊科(Compositae)、唇形科(Labiatae)和蔷薇科(Rosaceae)为优势科;属的组成相对较为分散,寡种属和单种属占总属数的93.64%.(2)从分布区类型看,在科级水平上有11个类型,科的分布区类型以热带分布最多,达47.86%,热带分布的科多于温带分布的科(20.00%);在属级水平上有14个类型,属的分布区类型以泛热带分布最多(18.21%),其次是北温带分布(15.75%),热带分布略多于温带分布.这说明长宁竹海自然保护区种子植物丰富,分布区类型多样.此外,保护区内分布有楠木(Phoebe zhennan)等14种珍稀濒危保护野生植物.     

长春市景观绿地中地被植物的应用研究

探讨了地被植物的涵义、分类,以及在长春市景观绿地中的作用.简述了近些年一些城市园林绿地中地被植物种植资源的调查结果以及应用情况,总结了地被植物在长春市不同类型绿地中常见的配置形式.最后,提出了长春市绿化应用地被植物时应注意的一些问题.     

铬污染地区植物吸附重金属的研究

对重金属铬污染地区的植物吸收与富集重金属的研究表明：（1）铬污染地区植物各部位的Cr含量均超标;（2）铬污染地区植物各部位在不同采样单元中Cr含量基本上是取样点至铬渣堆的距离成反比;（3）铬污染地区各种植物各部位中Cr含量与土壤中Cr含量参考值的比值均在28．76％以上,具有较强的Cr吸收与富集作用,尤其是叶部最高达301．27％,其受铬渣飘尘有较大的影响．     

Relationship between stomatal density and the changes of atmospheric CO2 concentrations

The relationship between the stomatal density of five woody plants endemic to China, i. e.Eucommia ulmoides, Quercus liaotungensis, Q. glandulifera var.brevipetiolata, Cyclocarya paliurus andFicus heteromorpha, and the atmospheric CO₂ concentrations was studied by observations on leaves of the herbarium-stored specimms(1920s–1990s). The results showed that the stomatal density inEucommia ulmoides, Quercus liaotungensis andQ. glandulifera var.brevipetiolata decreased significantly in response to the elevated atmospheric CO₂ concentrations, while inCyclocarya paliurus it decreased slightly and inFicus heteromorpha there were no responses.     

兵团农九师165团草地资源及其主要特点

根据１９９２～１９９４年实地考察资料,阐述了１６５团基本自然条件,对草地植物成分进行了饲用分析,研究了该地天然草地资源,确定了草地类型分类系统,并对各类型草地自然、经济特征进行了综合分析,概述了当地草地资源的主要特点。     

Natriuretic peptide hormones promote radial water movements from the xylem of Tradescantia shoots

Immunological evidence suggests that plants, like vertebrates, contain natriuretic peptides (NPs) and that rat atrial NP (rANP) binds specifically to plant membranes and promotes concentration and conformation-dependent stomatal opening. Stomatal opening and specific increases in cGMP levels were also observed in response to immunoreactive plant NP (irPNP). Here we report that both 1 μM rANP and irPNP (100 ng total protein/100 μL) significantly increase radial water movements out of the xylem of shoots of Tradescantia multiflora. Enhanced radial water movements are also observed in response to the cell permeant cGMP analogue 8-Br-cGMP (100 nM). The water channel inhibitor mercuric chloride (HgCl₂) significantly inhibits radial water movements at concentrations of 50 μM, while the presence of 10 μM 2-hydroxyethylmercaptoethanol (ME) prevents the inhibitory effect of the mercurial. The guanylate cyclase inhibitor LY 83583 at a concentration of 20 μM and sodium azide (NaN₃) at concentrations of ≥ 1 μM both also reduce radial water movements. We therefore conclude that the regulation of radial water movement out of the xylem involves modulation of cGMP levels, water channels and respiration-dependent processes. In addition, we propose that NPs have a critical role to play in radial water movements out of the xylem and speculate that as in vertebrates, NP effects might, at least in part, be mediated via the regulation of guanylate cyclases and water channels. Received 15 June 1998; received after revision 7 August 1998; accepted 26 August 1998