铅锌胁迫对蓖麻种子萌发与根系形态的影响

采用盆栽试验,研究了不同浓度Pb~(2+)、Zn~(2+)胁迫对蓖麻种子萌发与根系形态发育的影响。结果表明:单一和复合Pb~(2+)、Zn~(2+)胁迫对蓖麻的种子萌发和根系形态指标都产生了不同的影响。单一Pb~(2+)浓度≤400 mg/kg时能促进蓖麻种子萌发及根系和幼苗的生长;单一Pb~(2+)浓度为600 mg/kg时,根系生长受到明显的抑制作用,较对照组的主根长、根表面积分别下降了87.7%、47.7%;单一Zn~(2+)浓度≥400 mg/kg时,主根长、根表面积比单一Pb~(2+)胁迫下降更明显,且抑制作用随着Zn~(2+)浓度的增加而增加。复合胁迫基质中,Zn~(2+)对植物根系发育与生长的抑制作用大于Pb~(2+),但Pb~(2+)能在一定程度上缓解高浓度Zn~(2+)对植物的抑制作用。     

PP333和TIBA对大叶黄杨根系形态及根系活力的影响

采用双因素随机区组设计,以绿篱植物大叶黄杨为试验材料,研究不同浓度PP333、TIBA对其根系形态及活力的影响,探讨化学修剪对绿蓠植物的养分吸收机理。结果表明:(1)单施PP333极显著提高了大叶黄杨根系形态、细根根系的形态、根系活力,且随着PP333浓度升高而增大。单施TIBA仅对根平均直径、根表面积、细根的各根系形态指标以及活跃吸收面积有显著促进作用,且均在TIBA50 mg/L时达到最大值;(2)PP333和TIBA的交互作用对根体积、细根根系形态以及活跃吸收面积、活跃比表面积有显著促进作用,其中根系体积、细根根系的根长和根体积在80 mg/LPP333与100 mg/LTIBA配合喷施下达到最大值,而细根根系的表面积、根系活跃吸收面积和活跃比表面积则在80 mg/LPP333与50 mg/LTIBA配合喷施下达到最大值。PP333和TIBA通过对细根形态的影响,显著提高了根系的吸收活力。     

水盐胁迫对上海常见4种绿化树种根系生长的影响

试验选取了上海较为常见的4种绿化树种,落羽杉、乌桕、栾树、喜树,针对上海泥质海岸沿海防护林的建设需要,对其进行了模拟海水的耐盐、耐水淹交叉胁迫处理。结果表明,栾树和喜树的根系在水盐胁迫环境中受到的影响比乌桕和落羽杉大,从根系表面积、长度、体积、平均直径来看,栾树和喜树的敏感程度比较大,均出现早期上升,中后期下降的情况。落羽杉和乌桕根系对环境的表现则不是那么明显。     

2种城市绿化树种根系分泌物对芘胁迫的响应

为分析不同浓度芘胁迫下植物根系分泌物的变化情况,进一步研究多环芳烃污染环境的植物修复机理提供科学理论和参考。选取栾树、樟树为试验对象,测定在不同芘浓度胁迫下(L_0:0 mg/kg;L_1:500 mg/kg;L_2:2 000 mg/kg)两种树种的根系分泌物的组成成分、总碳、总氮含量及根系活力吸收面积、磷酸酶活性吸收面积及其生长形态。结果表明:不同浓度芘胁迫下,2种绿化树种根系分泌物种类均发生明显变化,栾树根系分泌物中检测到化合物种类顺序为:L_1(20种) L_2(19种) L_0(15种);樟树根系分泌物中检测到化合物种类顺序为:L_1(14种) L_2(9种) L_0(7种)。不同浓度的芘胁迫改变了植物根系的活性吸收能力,且低浓度的胁迫可以促进植物的生长。本研究可为城市绿化树种去除土壤中的多环芳烃提供科学参考。     

芘胁迫下紫玉兰根系活性及根系分泌物的响应

以紫玉兰为试验对象,设置三种芘处理浓度(L0:0 mg/kg,L1:500 mg/kg,L2:2000 mg/kg),采用气相色谱质谱联用技术(GC-MS)对根系分泌物的组分进行分析,测定根系分泌物中总碳(TC)和总氮(TN)及根系活性吸收面积,为进一步研究植物根系分泌物与多环芳烃污染修复的响应机理提供基础数据,也为进一步筛选植物修复树种提供依据。结果表明:(1)随芘浓度升高,根系分泌物中检测的物质种类减少;(2)芘胁迫下根系分泌物中化学成分变化较大;(3)紫玉兰根系活性吸收面积及酸性磷酸酶活性均不存在显著相关性;(4)根系分泌物中TC含量随着芘胁迫浓度的升高呈下降趋势,而TN含量呈上升趋势。试验结果表明植物的生理过程比植物结构特征对芘胁迫更为敏感。     

氯化钠胁迫对小叶女贞幼苗的影响

应用根系分析软件,研究了水培条件下不同浓度氯化钠处理对小叶女贞幼苗根系的形态结构和生理特征的影响。结果表明：不同浓度氯化钠胁迫处理15天后,根系总长度、主侧根长度、平均直径、表面积、体积随着盐浓度的增加而减小。随着盐浓度的增加,根系中细根比例减少,侧根生长比主根生长更易受到氯化钠抑制。     

底部渗灌对薄壳山核桃根系保护酶活性的影响

为给底部渗灌应用于育苗生产提供理论依据,以薄壳山核桃1年生容器实生苗为试材,研究了底部渗灌对不同生长时期的幼苗根系活力及保护酶类的影响。结果表明,底部渗灌显著促进了生长初期薄壳山核桃容器苗根系TTC还原强度,达到362.83μg/(g·h),显著高于上方喷灌苗木根系还原强度,且生长中后期也能保持较高水平的根系活力;底部渗灌处理后,苗木根系MDA含量及SOD、POD和CAT保护酶活性变化趋势与上方喷灌苗木一样,均表现出先上升后下降的趋势,说明底部渗灌对生长初期苗木根系有一定的胁迫,苗木通过提高根系中保护酶的活性减轻伤害,不断适应根系环境。     

硝基芳香化合物罗硝唑对冬珊瑚幼苗根系发育的影响

摘要：本研究以冬珊瑚幼苗为实验材料,在MS培养基中加入不同浓度的罗硝唑,探究其对植物根系发育的影响。结果表明：不同浓度罗硝唑的处理导致根系总长度、下胚轴长、根体积、根尖数、根系分叉数、根系表面积和投影面积、生物量及根茎比等表现出显著（P〈0．05）或极显著（P〈0．01）差异。根系总长度随着浓度的增加而减小,根系下胚轴长度随着浓度的增加而增加,根段平均直径随着罗硝唑浓度增加同时增加,坦没有显著性差异（P〉0．05）;外源罗硝唑的使用降低了冬珊瑚幼苗根系的侧根的形成,而且也会导致根系分叉数、根系表面积及投影面积下降;根系高度在各处理之间均没有显著性差异（P〉0．05）,幼苗根系外部途径长度在各处理之间差异也都不显著（P〉O．05）;随着外源罗硝唑浓度的增加,冬珊瑚幼苗生物量逐渐下降,低浓度的罗硝唑可增加根茎比,而高浓度则降低根茎比。     

辽东山区紫椴与糠椴铝胁迫下根系的变化特性

利用组织培养方法,研究了紫椴与糠椴在铝胁迫情况下,二者根系干物质、根系氧化力、培养液中沉淀量以及根系相对外渗电导率的不同变化特征,结果表明:随着铝浓度的逐渐增加,紫椴与糠椴两个树种根系干物质、根系氧化力都呈减少的趋势,而紫椴受到铝胁迫的影响要明显小于糠椴;根系细胞膜脂过氧化物含量上升,细胞电解质外渗率增加,木质化程度增大,糠椴沉淀量的增加幅度大于紫椴,但数量上紫椴要高于糠椴。     

干旱胁迫对真桦根系形态及生物量分配的影响

通过人工控水土培方法,研究了干旱胁迫对真桦的根系形态、分级特征、苗高生长以及生物量分配的影响。结果表明,干旱胁迫显著影响真桦根系形态及构型,随着土壤含水量的降低,真桦根系质量和平均直径降低。轻度和中度干旱使真桦根系总长度、根系表面积、比根长降低;重度干旱下,直径小于0.5 mm的细根比例显著提高,根系总长度、根系表面积、比根长显著提高。随着土壤含水量的降低,真桦苗木的高生长受到抑制,生物量降低,根冠比明显提高。     

SO2胁迫下11个园林绿化树种光合色素含量的变化

对11个园林绿化树种的2年生苗进行SO2胁迫处理,并对其叶片光合色素含量进行了测定与分析,在此基础上初步探讨了树种对SO2胁迫的抗性机理,并着重探讨了类胡萝卜素的作用。     

北京市9种常见绿化树种吸收积累SO_2能力研究

[目的]探究北京市9种常见绿化树种吸收积累SO_2能力,择优筛选净化大气理想树种,为未来北京城区绿化结构调整提供科学依据。[方法]采用BaSO_4比浊法测定北京市9种常见绿化树种在不同污染条件下叶片硫含量,通过计算相对吸硫量并利用平均污染指数法评价其对SO_2的吸收净化能力,比较相互间差异性,筛选出吸收净化SO_2能力强的树种。[结果]表明:(1)不同污染条件下,同种绿化树种叶片硫含量及相对吸硫量普遍存在显著性差异,随着环境污染水平的增强,叶片硫含量和相对吸硫量呈现逐渐增高的趋势;(2)相同污染条件下,不同绿化树种吸收净化SO_2能力普遍存在显著性差异,表现为旱柳吸收能力极强,其平均相对吸硫量2.38 mg·g~(-1),平均污染指数为2.23;国槐吸收能力强,其平均相对吸硫量1.18 mg·g~(-1),平均污染指数为2.09;臭椿、黄栌、毛白杨、色木槭吸收能力中等;榆树、侧柏、油松吸收能力相对较弱。[结论]不同污染环境条件下,同种绿化树种叶片硫含量和相对吸硫量均呈现出随着环境污染水平逐渐的增强而逐渐升高的趋势;而在相同污染环境条件下,不同绿化树种叶片硫含量和相对吸硫量均存在显著性差异。旱柳和国槐可以作为北京市城市绿化用以净化SO_2的理想树种。     

银川市几种常见绿化树种净化SO_2潜力比较

比较银川市9种绿化树种SO2净化潜力de1结果表明,各绿化树种随着月份变化SO2净化潜力不同。其中,梓树、河北杨、白蜡、垂柳、悬铃木均从6月份开始上升,到8月份开始下降,9月份后又有所上升;国槐、丝棉木、金叶榆、龙爪槐则一直表现为先缓慢上升然后又缓慢下降的趋势。各绿化树种在同一时间的SO2净化潜力也不相同。其中,净化潜力最强的是国槐,最大净化值为8.620kg/株;其他树种的净化潜力依次为梓树、河北杨、白蜡、垂柳、悬铃木、金叶榆、龙爪槐、丝棉木。     

3个竹种硫含量季节变化

在福建农林大学百竹园内随机选取3个竹种:歪脚龙竹、坭竹、长叶苦竹,分别于春、夏、秋、冬4个季节对其叶片、主枝、小枝的硫含量进行测定,同时以福州市森林公园相同竹种作为参照。结果表明:竹类植物叶片硫元素含量最高,各竹种之间硫元素含量差异显著;同竹种不同季节的各部位的硫含量均有变化,秋季硫含量最高,夏季最低,较秋季平均减少54.88%;竹类植物对于硫元素的吸收作用较强,叶片硫含量均高于国标的最高值2.0 g.kg-1,且叶片硫含量对环境二氧化硫变化具有指示作用,可以考虑作为硫污染区的绿化植物。     

海南岛热带天然次生林生长动态研究

本文对两类处于不同演替阶段的天然次生林,从直径生长、胸高断面积生长、材积生长、林木死亡率等方面进行了对比分析。研究结果表明:随着演替的进程,天然次生林直径生长、胸高断面生长和材积生长呈现下降趋势,林木死亡率也呈现明显的下降趋势,其主要原因是,在演替的早期阶段,速生喜光先锋种在林分中占据较高比例,进而林分表现出较高的死亡率和较高的生长力,但是随着演替的进行,喜光先锋速生树种逐步被耐荫的顶级或亚顶级树种所取代,进而表现出低生长和低的死亡率。     

Oak seedling growth and ectomycorrhizal colonization are less in eastern hemlock stands infested with hemlock woolly adelgid than in adjacent oak stands

Invasive, non-indigenous, phytophagous insects have caused widespread declines in several dominant tree species. The decline in dominant tree species may lead to cascading effects on other tree and microbial species and their interactions, affecting forest recovery following the decline. In the eastern USA, eastern hemlock (Tsuga canadensis (L.) Carr) is declining because of infestation by the hemlock woolly adelgid (HWA; Adelges tsugae Annand). Northern red oak (Quercus rubra L.) is a common replacement species in declining hemlock stands, but reduced mycorrhizal inoculum potential in infested hemlock stands may cause oak to grow more slowly compared with oak in oak stands. We grew red oak seedlings for one growing season in declining hemlock-dominated stands infested with HWA and in adjacent oak-dominated stands. Ectomycorrhizal root tip density and morphotype richness in soil cores were 63 and 27% less, respectively, in declining hemlock stands than in oak stands. Similarly, ectomycorrhizal percent colonization and morphotype richness on oak seedlings were 33 and 30% less, respectively, in declining hemlock stands than in oak stands. In addition, oak seedlings in declining hemlock stands had 29% less dry mass than oak seedlings in oak stands. Analysis of covariance indicated that morphotype richness could account for differences in oak seedling dry mass between declining hemlock stands and oak stands. Additionally, oak seedling dry mass in declining hemlock stands significantly decreased with decreasing ectomycorrhizal percent colonization and morphotype richness. These results suggest that oak seedling growth in declining hemlock stands is affected by reduced ectomycorrhizal inoculum potential. Further, the rate of forest recovery following hemlock decline associated with HWA infestation may be slowed by indirect effects of HWA on the growth of replacement species, through effects on ectomycorrhizal colonization and morphotype richness.     

森林生态系统服务功能价值评估方法研究综述

森林生态系统是陆地上最为复杂的生态系统,它不但拥有丰富的资源,还具有巨大的环境调节功能和生态社会效益.介绍了森林生态系统中没有普通意义上的市场的一些生态服务功能价值评估和计算方法,并评价了这些方法的优劣;系统阐述了森林生态系统提供林产品、涵养水源、防洪效能、保持水土、保持养分、防止泥沙淤积、固定CO2、释放O2、吸收SO2、截留粉尘和净化大气功能的生态价值评估方法.     

Can picnic influence floral diversity and vitality of trees in Bhawal National Park of Bangladesh?

We examined the impact of picnic activities on forest diversity, structure, regeneration and vitality of tree species in the Bhawal National Park of Bangladesh. The study area was classified as a non-used, occasionally used and frequently used area on the basis of the intensity of the picnic activities. A total of 43 plant species were enumerated in the whole study area. The highest plant species richness (41 species) was observed in the non-used area whereas the lowest species richness (11 species) in the frequently used area. The diversity index decreased with the increase of picnic intensity whereas the concentration of dominance increased. Density of all plant groups except mature trees, and the basal area of the mature trees showed a declining trend from the non-used to frequently used area. The frequently used area exhibited very poor regeneration. Tree vitality decreased with the increase of picnic intensity. The relevance of our study as a basis for further research to determine the impact of tourism on biodiversity in Bangladesh is discussed.     

Effects of landscape patterns on species density and abundance of trees in a tropical subdeciduous forest of the Yucatan Peninsula

Most studies of the effects of fragmentation and landscape patterns on plant communities focus on particular patches and on local species richness (α-diversity), while few studies examine different patch-types at the whole landscape level and address effects on abundance and composition of species or functional groups. The present study aims to identify and characterize relationships between patch-type metrics and species density and abundance of trees using four tropical subdeciduous forest landscapes in the Yucatan Peninsula considering the entire landscape as the unit of study. Species density and abundance of different groups of tree species resulting from hierarchical clustering were related to landscape patterns of patch-types (area, edge, shape, similarity and contrast) using regression analysis and Akaike Information Criterion (AIC). The abundance of tree species in the oldest stages of succession was associated with percentage of land of a patch-type. Total area may favor the establishment of shade-tolerant tree species in the study area because as the area of forest patches increases, the area of forest interior conditions also increases. Conversely, the abundance of species at early and intermediate stages was related to total edge contrast and edge density, respectively. Fragmentation increases the proportion of edge zones of a patch-type, creating contrasting microclimate conditions that could promote the establishment of pioneer and light-demanding species. Thus, the combined effect of total area and edge length of a patch-type may enhance total tree species richness in the study area by favoring species with different life-history strategies. The appearance of area, shape, edge and contrast in most of the regression models suggests that some generalization can be made about the effects of spatial geometry of patch-types on species composition and abundance of tropical trees. Understanding associations between landscape metrics and species density and abundance of objectively derived groups or guilds of species can provide important insights on the effects of fragmentation and landscape pattern on these guilds and on overall α-diversity, as well as guidelines for their conservation and management.     

桤木、马褂木在鄂西山区水土保持建设中的应用

摘要：为了增加鄂西山区水土保持林树种,促进区域林业项目建设和林种结构调整,本文选择桤木、马褂木、多土树种营建水土保持试验林,以生长量、郁闭度、根系生长量、地表枯枝落叶量等因子进行对比分析。结果表明：桤木、马褂木适应鄂西山区造林环境,成活率高,生长较快,林分郁闭快,根系发达,地表枯枝落叶量大,有良好水土保持和水源涵养能力;抚育管理难和成本低,经济效益较显著,能在鄂西山区水土保持建设中发挥示范作用。