干旱胁迫下镉处理对互叶醉鱼草幼苗生长、镉积累及光合生理的影响

为探究干旱条件下,互叶醉鱼草(Buddleja alternifolia Maxim.)幼苗对重金属镉胁迫的生长及光合生理响应机制,以两年生互叶醉鱼草幼苗为试验材料,设置对照与干旱两个水分处理组(土壤相对含水率分别为:65%—60%,35%—30%),每个水分处理条件下再分别设置3个镉处理浓度(0.28、(0.6+0.28)、(1.2+0.28)mg/kg),共6个处理。测定不同水分及镉处理对互叶醉鱼草生长、生物量、光合参数及体内重金属含量的影响。结果表明:干旱与镉复合胁迫下植物的存活率为100%。镉胁迫、干旱与镉复合胁迫均不同程度抑制了互叶醉鱼草幼苗生长、生物量积累、植株的光合作用及叶绿素含量,且其光合和叶绿素含量的降幅明显大于单一镉胁迫。镉胁迫下,互叶醉鱼草幼苗单株最高镉富集量为69.33 mg/kg,而复合胁迫下单株最高镉富集量为50.68 mg/kg。以上结果表明:干旱胁迫能够加重镉胁迫对植物的影响,使复合胁迫下互叶醉鱼草生长、光合生理及镉富集能力下降。但单一镉胁迫下,互叶醉鱼草对镉具有更强的耐受性,并有较高的生物富集能力,且干旱与Cd复合胁迫下互叶醉鱼草幼苗仍有一定的镉积累量。因此在干旱半干旱区园林绿化以及Cd污染地区的生态建设中,互叶醉鱼草是一种具有巨大应用潜力和前景的灌木树种。     

裸花紫珠嫩枝扦插生根影响因子研究

以2年生实生苗的嫩枝为试材,从基质、插条部位、留叶方式、扦插季节、外源激素种类及浓度5个方面对裸花紫珠的扦插生根因子进行了系统研究。测定插穗的生根率、偏根率、生根数量及最大根长,采用隶属函数值对扦插生根效果进行综合评价。结果表明:(1)8个基质处理中,以泥炭∶蛭石∶河沙按2∶1∶1体积比混合的基质扦插效果最好,生根率74%,平均生根数5.4条;(2)插条中、上部制取的插穗扦插效果优于下部,且中部插穗的生根质量最佳;(3)插穗留叶处理的生根率显著高于不留叶处理,留两片半叶(1/2叶)时,生根率可达64%;(4)秋季(9月)为扦插最适宜季节,生根数量和最大根长均显著高于春季(4月)和夏季(7月);(5)4个浓度下,IBA处理的生根质量均高于IAA和NAA处理,其中IBA(1 000、1 500 mg·L~(~(-1)))处理的扦插效果较好,而高浓度NAA(2 000、2 500 mg·L~(~(-1)))处理明显不利于生根。     

广东天井山莽山红山茶分布地调查及其扦插育苗

以莽山红山茶为研究对象,对其天井山分布地进行调查,并开展扦插育苗研究。结果表明,莽山红山茶喜温暖湿润环境,分布区狭隘,自然繁育困难;在扦插育苗中,生根剂IBA处理的生根效果优于NAA和ABT,其扦插成活率和生根率均较高,且以900 mg·L~(-1) IBA处理60 min最佳,生根率为33.33%。     

茶树嫩枝扦插的高效方法

茶(Camellia sinensis)是世界上最重要的饮料作物之一, 随着种植面积的扩大, 茶苗的需求量也日益增加。传统的扦插育苗方式存在着生根难、周期长和取材难等问题, 因此优化扦插生根的方法十分重要。该研究以较易获得、但传统方法难以生根的绿色嫩枝为扦插材料, 首先对培养介质进行改良。与土培和水培相比, 利用海绵培养可以使茶树幼嫩插穗在1个月之内快速生根, 生根率达32.2%。其次, 对海绵培方法做进一步优化, 确定一芽一叶的幼嫩短穗生根潜力更佳; 同时, 添加生根粉能够促进茶树茎部愈伤组织与根系的形成, 其中1.25 g?L ^-1生根粉处理48小时对茶树扦插快速生根最有效, 生根率达42.0%。综上, 通过优化培养介质和扦插材料以及适当添加生根粉等措施, 建立了一种茶树高效嫩枝扦插生根的方法。该方法能够显著缩短嫩枝插穗的生根时间, 突破了扦插材料的限制, 有效降低了扦插成本, 具有重要的应用前景。     

茶树嫩枝扦插的高效方法

茶(Camellia sinensis)是世界上最重要的饮料作物之一, 随着种植面积的扩大, 茶苗的需求量也日益增加。传统的扦插育苗方式存在着生根难、周期长和取材难等问题, 因此优化扦插生根的方法十分重要。该研究以较易获得、但传统方法难以生根的绿色嫩枝为扦插材料, 首先对培养介质进行改良。与土培和水培相比, 利用海绵培养可以使茶树幼嫩插穗在1个月之内快速生根, 生根率达32.2%。其次, 对海绵培方法做进一步优化, 确定一芽一叶的幼嫩短穗生根潜力更佳; 同时, 添加生根粉能够促进茶树茎部愈伤组织与根系的形成, 其中1.25 g∙L ^-1生根粉处理48小时对茶树扦插快速生根最有效, 生根率达42.0%。综上, 通过优化培养介质和扦插材料以及适当添加生根粉等措施, 建立了一种茶树高效嫩枝扦插生根的方法。该方法能够显著缩短嫩枝插穗的生根时间, 突破了扦插材料的限制, 有效降低了扦插成本, 具有重要的应用前景。     

浅谈杨树扦插育苗造林技术

扦插育苗造林可以保持植物母株的自体优良基因,不像播种繁殖会产生变异,苗木生长较迅速,对生产力和经济效益来讲是较高的选择。本文从培育插穗条、使用微量元素和覆膜扦插等方面,对杨树的扦插、育苗的造林技术进行了探讨。     

IBA浓度、扦插时间对江西杜鹃和百合花杜鹃扦插生根的影响

为探明有鳞大花亚组杜鹃扦插生根的最佳IBA浓度和扦插时间,该研究以江西杜鹃、百合花杜鹃为材料,分别采用腐叶土+河沙(1:1)、泥炭+珍珠岩+蛭石(3:1:1)基质,开展了4个IBA浓度和4个扦插时间的生根试验.结果表明:IBA浓度对除老叶留存数外的所有指标有显著影响,其中100 mg·L-1 IBA处理生根率、新梢长最大,腐烂率最低,其它指标也表现良好,为最佳生根浓度;50 mg·L-1 IBA处理根幅、新梢率最大,但不定根数最少,效果其次;200 mg·L-1 IBA处理促进根系生长,但生根率较低、特别是显著抑制新梢发育;对照处理生根效果最差.扦插时间对所有生根指标均有显著影响,早春(04-18)木质化硬枝扦插除老叶留存数较差外,其它指标均表现极佳,为最适扦插时间;秋季(10-19)半木质-木质化过渡枝扦插效果其次;夏季(06-21)嫩枝及(08-16)半木质化枝生根效果极差,不宜进行扦插育苗.物种、基质对生根指标也有显著影响,百合花杜鹃扦插生根能力强于江西杜鹃,泥炭+珍珠岩+蛭石(3:1:1)基质生根效果优于腐叶土+河沙(1:1).该研究结果首次发现早春新梢萌发前采用木质化硬枝扦插可以显著提高两种杜鹃的生根效果,为该亚组杜鹃的扦插育苗提供了科学依据.     

桑树扦插的生根生理

桑树是多年生木本植物,历来采用嫁接繁殖。与嫁接法相比,扦插繁殖不仅有保持亲本遗传性状的特点,同时还有育苗时间缩短1年的优点。但扦插繁殖有一定的难度。为了克服扦插生根困难,我们对桑树扦括生根机理与技术作了不少研究,80年代湖桑扦插育苗技术有了重大突破,在生产上已开始采用。现简要归纳如下。1．桑树扦括生根部位主要有两处：一是位于桑芽两侧和下方,即叶基部位。该处生有根原基,桑树扦插后由根原基萌生新根。成熟的根原基突出条面,形成斜尖,它已具根组织的雏型。桑树根原基的多少及在枝条上的部位与品种、枝条成熟度有关…     

千层金嫩枝扦插繁殖技术

本研究用L_(16)(4~5)正交试验方法,研究了基质、穗条长度、植物生长调节剂及其浓度对千层金嫩枝扦插生根率的影响.结果表明,基质和生长调节物质对生根率有极显著的影响,而植物生长调节剂浓度与穗条长度对生根率有显著的影响,4个因素对干层金嫩枝大田扦插生根率影响从大到小分别是基质、生长调节物质、植物生长调节剂浓度和穗条长度.用浓度100 mg/L的NAA浸泡9 cm插穗2 h,在混和基质上扦插,平均生根率可达92%,且生根及新梢抽出时间早,侧根数量多,扦插效果最好.     

云南蕊帽忍冬的扦插育苗方法研究

云南蕊帽忍冬(Lonicera pileata Oliv.f.yunnanensis(Fr.)Rehd)是分布于云南、四川等地海拔2100—3200米处的常绿或半常绿小灌木,现主要开发作为盆景材料和绿篱植物。本文研究了该植物的扦插育苗方法,结果表明,云南蕊帽忍冬的扦插育苗可全年进行,应利用当年抽生的木质化或半木质化枝顶段或中段作为插条,长5—6厘米,用IAA 2000ppm快蘸后插入滇池草炭或红土或炉渣中,在温度15-38℃,平均空气相对湿度87.9%以上,透光约50%全光照条件下,30—50天内可得到好的生根苗;芽和叶在云南蕊帽忍冬的扦插生根中起重要作用,采条时要避免它们的损坏和脱落,本文还对在6-8月份抽生枝最旺盛的期间,在昆明的露地进行了扦插育苗试验,认为露地扦插后,插床用白色塑料薄膜封闭,竹帘遮荫,插条生根最好。     

干旱对白皮松幼苗针叶生理特性的影响

试验目的是研究栽植前和栽植后干旱致使白皮松（Pinus bungeana Zucc.）针叶的生理特性的改变,了解白皮松造林前后能够适应的干旱范围,为白皮松科学造林提供理论依据。试验中模拟白皮松容器苗造林前后可能遇到的干旱胁迫,研究栽植前容器苗分别为B1：75%～80%（正常浇水）、B2：55%～60%（轻度干旱）、B3：35%～40%（严重干旱）和栽植后土壤相对含水量分别为A1：75%～80%、A2：55%～60%、A3：35%～40%、A4：15%～20%（极严重干旱）对白皮松针叶的生理指标的影响。结果表明：栽植前白皮松容器苗经B3处理后,针叶电解质渗透率增加,叶绿素含量和PSII最大光化学效率（Fv/Fm）显著降低,表明针叶受到一定伤害。栽植后如果正常浇水,这些影响将消除,如果遭遇栽植后干旱,B3处理的受害程度不比B1和B2处理深。栽植后白皮松经A3和A4处理4周后,针叶的电解质渗透率增加,Fv/Fm降低,表明白皮松针叶受到伤害。白皮松容器苗造林在栽植前遭到适当干旱胁迫时不会影响造林后的表现。但应避免栽植后初期4周以上严重干旱胁迫。     

Six endemic plant species from central Argentina: an evaluation of their conservation status

The purpose of this study is to determine the conservation status of six vascular plant species with a restricted distribution or endemic to the mountainous areas in the province of Córdoba, central Argentina, by using the IUCN 1994 Red List Categories. The population number was estimated using a statistical method based on field data. The predicted decrease in the population number on a 10 yr projection was estimated taking into account the area to be used for future afforestation programs. To determine the area of occupancy and the extent of occurrence, an exhaustive bibliographical survey was carried out and herbarium specimens deposited in several institutions were revised. Aa achalensis, Adesmia cordobensis, Buddleja cordobensis, Croton argentinus and Oenothera cordobensis were considered as Vulnerable, whereas Solanum restrictum was assigned to the Endangered category. The categories assigned to Aa achalensis and Solanum restrictum are considered at the global level, whereas those assigned to Croton argentinus, Oenothera cordobensis, Adesmia cordobensis and Buddleja cordobensis should be considered at the local level. In all six cases the risk of extinction is high and suitable conservation strategies should be developed for each species. The most important threat factor is the planned afforestation in the area using exotic timber species; under these conditions the creation of a reserve in the studied area would be desirable in order to conserve five of the plants studied and, considering that 95% of its species are indigenous, the local flora as a whole.     

科尔沁沙地不同造林类型对土壤动物多样性的影响

为深入认识流沙生境中种植人工林对土壤动物多样性的影响,选择科尔沁流动沙地及其周围灌木林和乔木林地(生长年龄均为30年左右)为研究样地,对土壤动物群落与土壤环境进行调查,分析了土壤动物群落结构对流动沙地种植人工林的响应及影响因素.结果表明:流动沙地种植人工林对土壤性状产生显著影响,尤其是灌木林覆盖流动沙地显著改善了土壤环境,增加了土壤水分,提高了土壤营养条件.在3种林地中共捕获土壤动物485只、11个类群.优势类群为蜱螨目和弹尾目,常见类群为啮目,其他8个类群为稀有类群.从流动沙地到灌木林地和乔木林地,土壤动物密度减少,类群数和Shannon指数增加,而均匀度指数下降.但土壤动物密度、类群数、Shannon指数和均匀度指数在3种样地间均无显著性差异.土壤电导率是影响土壤动物类群数分布的重要因素.在科尔沁沙地,流动沙地种植人工林能够改善土壤环境和影响土壤动物多样性,但以30年的人工林研究其对流动沙地土壤动物群落的影响存在局限性.     

Trade-offs between plant species richness and carbon storage in the context of afforestation – Examples from afforestation scenarios in the Mulde Basin,Germany

The German Federal State of Saxony aims to increase forest cover, supported by the implementation of afforestation programs. To analyze consequences of an increase in forest cover, this study investigates possible trade-offs between carbon storage and plant biodiversity caused by afforestation. Six afforestation scenarios with total forest cover ranging from 27.7% to 46% were generated in the Mulde river basin in Saxony with regard to different forest types. Carbon storage was calculated by the process-based Dynamic Vegetation Model LPJ-GUESS while random forest models were used to predict changes in plant species richness. We used eight different plant groups as responses: total number of plant species, endangered species, as well as species grouped by native status (three groups) and pollination traits (three groups). Afforestation led to an increase in carbon storage that was slightly stronger in coniferous forests as compared to deciduous forests. The relationship between plant species richness and afforestation was context dependent. Species richness showed a non-linear relationship with forest cover share. The relationship was influenced by shares of land use types, climatic conditions and land use configuration expressed by the number of land use patches. The effect of forest type on plant species richness was marginal. On average the relationship between carbon storage and plant species richness was synergistic for most plant groups. However, the relationship between change in species richness and change in carbon storage varied across space. This changing relationship was used to identify priority areas for afforestation. The different plant groups responded differently to an increase in forest cover. The change in species richness for Red List species was relatively distinct from the other species groups. Neophytes and archeophytes (i.e. alien plant species introduced after and before the discovery of the Americas) showed a similar response to the afforestation scenarios. While afforestation had overall positive effects both on plant species richness and carbon storage, a number of locations were identified for which afforestation would lead to a decrease in plant species richness. Spatial planning should therefore avoid afforestation at these locations.     

Impact of afforestation-associated management changes on the carbon balance of grassland

Afforestations can be considerable carbon (C) sources due to C losses from the soil after site preparation for tree planting and decreased primary production. In this study, the transition from grassland to afforestation was investigated using two eddy flux towers, which were operated in parallel for 3 years, one on a young afforestation and one on an adjacent grassland. Differences between the fluxes at the two sites were attributable to the management of the sites, without confounding influences of meteorological variability. Site preparation with deep ploughing of the planting rows destroyed 30% of the grassland vegetation at the afforestation site and reduced gross primary productivity by 41% in the first year. At the afforestation site 38 g m^?2 less C was sequestered compared with the nonafforested grassland during the first year. In the following years, the C sink at the afforestation site was higher than at the grassland indicating that soil C loss due to site preparation and land use change on the afforestation occurred only during the first year. Metrological conditions, especially summer drought, caused a high interannual variability of the C balance: both sites were small C sources in 2005 (67 g C m^?2 a^?1 at the grassland and 19 g C g^?1 a^?1 at the afforestation site) and small C sinks in 2004 and 2006 (?72.5 and ?16 g C m^?2 a^?1 at the grassland and ?34 and ?61 g C g^?1 a^?1 at the afforestation). Sheep grazing and mowing affected the short‐term dynamics of the C balance and sheep grazing accelerated the C turnover on the grassland site. The investigated afforestation site did not provide any short‐term way of sequestering additional C even though soil C losses during the first 3 years were relatively small.     

菌根及其在荒漠化土地恢复中的应用

对菌根的作用及其荒漠化对其影响,以及菌根在荒漠化土地恢复中的应用进行了探讨,指出菌根不仅能够促进植物个体养分的吸收,提高植物光合作用,增强植物抗旱、抗盐性,而且能够调节群落内植物间的关系、群落的演替轨道及其生物多样性、耕作、灌溉、过度放牧和开矿等诱发土地荒漠化过程的人类活动直接影响菌根的建立和生存,采用外来菌引入及原来残存菌培育,在恢复区建立丛状菌根植物,菌木化菌根造林及开矿土地管理中表土的存贮等方式都会有力地促进恢复地菌根的建立,并可缩短恢复周期。     

The impact of ecological restoration on ecosystem services change modulated by drought and rising CO2

Ecological restoration projects (ERPs) are an indispensable component of natural climate solutions and have proven to be very important for reversing environmental degradation in vulnerable regions and enhancing ecosystem services. However, the level of enhancement would be inevitably influenced by global drought and rising CO₂, which remain less investigated. In this study, we took the Beijing-Tianjin sand source region (which has experienced long-term ERPs), China, as an example and combined the process-based Biome-BGCMuSo model to set multiple scenarios to address this issue. We found ERP-induced carbon sequestration (CS), water retention (WR), soil retention (SR), and sandstorm prevention (SP) increased by 22.21%, 2.87%, 2.35%, and 28.77%, respectively. Moreover, the ecosystem services promotion from afforestation was greater than that from grassland planting. Approximately 91.41%, 98.13%, and 64.51% of the increased CS, SR, and SP were contributed by afforestation. However, afforestation also caused the WR to decline. Although rising CO₂ amplified ecosystem services contributed by ERPs, it was almost totally offset by drought. The contribution of ERPs to CS, WR, SR, and SP was reduced by 5.74%, 32.62%, 11.74%, and 14.86%, respectively, under combined drought and rising CO₂. Our results confirmed the importance of ERPs in strengthening ecosystem services provision. Furthermore, we provide a quantitative way to understand the influence rate of drought and rising CO₂ on ERP-induced ecosystem service dynamics. In addition, the considerable negative climate change impact implied that restoration strategies should be optimized to improve ecosystem resilience to better combat negative climate change impacts.     

季节性干旱地区典型树种长期水分利用特征与模式

在季节性干旱地区,水分是影响植物生长发育的关键核心因子。基于长期连续观测数据探究植物水分利用模式,对于季节性干旱地区植被建设具有重要意义。本研究以北京山区侧柏人工林为对象,利用稳定氢氧同位素技术测定了2012—2017年间土壤、植物枝条和降水同位素组成,通过MixSIAR模型定量分析侧柏对不同土层土壤水分的贡献率。结果表明: 深层(40～100 cm)土壤水较浅层(0～40 cm)土壤水稳定,受蒸发和降水的影响,浅层土壤含水量和水同位素值变化幅度较深层明显;侧柏主要吸收利用稳定的深层土壤水,贡献率为55.7%。在旱季,随着土壤水分含量的降低,植物对土壤水分的吸收深度逐渐向浅层转移;在水量充沛、自然适宜、轻度干旱、中度干旱条件下,深层土壤水的贡献率依次为59.8%、57.9%、54.6%、52.7%。在轻度和中度干旱条件下,雨季侧柏对深层土壤水的依赖程度高于旱季,以维持较大的蒸腾作用;在水量充沛、自然适宜、轻度干旱、中度干旱条件下,深层土壤水贡献率分别为58.9%、57.6%、56.4%、57.1%。侧柏依据土壤水分条件调整吸水深度的自适应特性,对季节性干旱地区生态造林树种的选择和长期管理规划具有重要意义。     

南亚热带10种造林树种的水力结构和水力安全

南亚热带地区人工纯林面积大, 但是结构简单, 对气候变化响应敏感。在区域气候干旱化的背景下, 造林树种的生理生态策略及其对季节性干旱的响应亟待研究。该研究选择南亚热带地区10种造林树种(包括6种乡土种和4种外来种), 测定这些树种的平均生长速率、水力学性状以及经济学性状, 分析性状与生长速率之间的相关关系, 并比较水力安全边际和气孔安全边际的种间差异。结果发现: (1)造林树种的生长速率与木质部导水率显著正相关, 但与木材密度、比叶面积以及水力安全性指标无显著相关性。(2)造林树种的水分传导效率性和安全性之间没有权衡关系, 外来树种Acacia crassicarpa和Eucalyptus grandis × urophylla同时具有较高的木质部导水率和较强的抗栓塞能力。(3)造林树种的水力安全边际和气孔安全边际的种间差异显著, 大叶相思(Acacia auriculiformis)、红锥(Castanopsis hystrix)、壳菜果(Mytilaria laosensis)和阴香(Cinnamomum burmannii)在干季发生水力失败的风险较高。建议南亚热带人工林的生态监测指标体系中应包括树木水力学性状, 进而为人工林的可持续经营管理提供重要参考。     

北京地区不同地形条件下的土地覆盖动态

利用MSS/TM影像和1∶250 000 高程数据分析了1978~2001年北京地区土地覆盖的变化。为研究人类活动对土地覆盖类型及植被变化的影响,根据植被的分布规律和人类活动影响,利用数字高程模型(DEM)将研究区遥感影像分为不同海拔段,分别建立标志进行解译。通过转移概率矩阵计算、不同地形因子影响下的土地覆盖类型分布的GIS分析,得到如下结果:1) 1978~2001年间北京市土地覆盖变化主要发生在平原和低海拔、小坡度的平缓地区,表现为农业用地向城镇用地的转变;高海拔地区主要为天然植被所覆盖,土地覆盖变化相对较小,主要是灌丛向林地的转变。2) 地形因子显著影响土地覆盖类型的分布及变化。随着海拔的升高和坡度的增大,农业用地和城镇用地减少,林地和灌丛逐渐增加。坡向对植被的分布也有较大影响。