利用RAPD标记评价桃种间杂交一代群体的分离方式

以毛桃2-7(Prunus persica)、山桃白山碧桃(Prunus davidiana)以及两者的F_1代为试材,对RAPD标记的分离方式进行分析。结果表明,RAPD标记在F_1代呈3种分离方式:孟德尔分离、偏离孟德尔分离规律、异常分离。3种分离位点出现的频率和数量分别为:80%、240,14%、42,6%、18。呈孟德尔分离的情况有:不分离、1:1分离和3:1分离,其中不分离的频率为64％。并对偏离孟德尔分离比例和异常分离的RAPD标记进行分析。其研究结果可为该群体是否适合构建遗传连锁图谱进行评价及进一步利用该群体奠定良好基础。     

春兰菌根真菌的分离及培养特征研究

采用改良PDA分离培养基,通过切片法从春兰(Cymbidium goeringii Rchb.f.)菌根中分离内生真菌,并用打孔法分离得到纯化菌株。初步鉴定为6株内生真菌(LC-1、LC-2、LC-3、LC-4、LC-5、LC-6)。结果表明:切片分离时的表面消毒条件和方法以及分离培养基的选用,均直接影响菌根真菌的分离纯化结果,及分离得到的内生菌的多样性。以75%酒精处理30 s+0.1%升汞处理5 min进行表面消毒,效果稳定,配合改良的PDA培养基分离内生菌,可以分离出较多的内生菌种类。     

RAPD标记在苹果属种间杂交一代的分离方式

以富士苹果和山定子及二者的种间杂交Ｆ１代为试材,对ＲＡＰＤ标记的分离方式进行了研究。结果表明,ＲＡＰＤ标记在Ｆ１代的分离方式可归为３类,即呈孟德尔分离、偏离孟德尔分离比例和异常分离。呈孟德尔分离的情况有：不分离（代表了父母本中相应ＲＡＰＤ标记的５种组合：ＡＡ×ＡＡ、ＡＡ×Ａａ、Ａａ×ＡＡ、ＡＡ×ａ、ａ×ＡＡ）、１∶１分离（代表了父母本中相应ＲＡＰＤ标记的２种组合：Ａａ×ａ、ａａ×Ａａ）和３∶１分离（代表了父母本中相应ＲＡＰＤ标记的１种组合：Ａａ×Ａａ）。异常分离的标记包括：Ｆ１代出现双亲均不具备的标记、分子量在不同Ｆ１个体间变化的标记,以及隔代遗传的标记。据对２００个ＲＡＰＤ标记的统计分析,不分离标记、按１∶１或３∶１比例正常分离的标记、偏离孟德尔分离比例的标记和异常分离标记分别占４５．５％、４５．０％、８．０％和１．５％;双亲共有标记中７４．７％不发生分离,单亲特有标记中５７．１％～７９．６％发生正常分离;富士特有标记中不分离标记占３３．３％,而山定子特有标记中不分离标记只占４．３％,表明富士基因组中纯合基因位点的比例要高于山定子。对异常分离的ＲＡＰＤ标记等进行了讨论。     

双孢蘑菇菌株As2796的提纯复壮

采用原生质体分离、菌丝尖端分离和组织分离3种方法对双孢蘑菇(Agaricus bisporus)As2796的退化菌株进行分离,应用灰色关联度分析法综合评价不同分离株的农艺性状,筛选综合性状优于As2796退化菌株的提纯复壮菌株.结果表明,3种分离方法均能获得提纯复壮的菌株,其中原生质体分离株P28的提纯复壮效果最好.     

海南栽培铁皮石斛菌根真菌的初步培养

运用孟加拉红抗生素培养基与PDA培养基,通过切片法从铁皮石斛菌根中分离内生真菌,并用打孔法分离得到纯化菌株。初步鉴定为5株内生真菌(D03、D07、D08、D12、D18)。结果表明:切片分离时的消毒时间和方法以及分离培养基的选用,均可影响菌根真菌的分离纯化结果,及分离得到的内生菌。以75%酒精处理40s+0.2%次氯酸钠处理5min进行消毒,效果较好,相对PDA培养基分离内生菌,孟加拉红抗生素培养基可以分离出较多的内生菌种类。     

蛹虫草高产优良菌株的选育

探索了尖头及圆头蛹虫草组织分离和孢子分离选育方法,分离的不同部位、酒精消毒等对蛹虫草菌株的性状影响;通过直接观察法、镜检法、出草试验等对分离筛选优良菌株进行确认。     

黑木耳纯菌种的筛选方法

黑木耳菌种的分离方法有三种:耳木组织分离、耳片组织分离、孢子弹射分离。分离时应注意以下事项: 一、标本的选择:采集春耳最好,四至五月采集,一定要耳大、肉厚、色黑、单朵重、无杂菌、无虫害。如耳木分离应与分离部位的耳朵一起采集,要注意了解耳木的营养状况如何,以便区分分离标本的优良性能。二、分离前要注意做好标本的处理:采集到的耳木要适当的凉干或风干,防止杂菌由两头截断处进入耳木,发生污染。     

外生菌根菌的分离与培养的研究进展

外生菌根菌在生态、经济等方面发挥的重要作用使其成为大型真菌领域研究及发展的主要对象。归纳了真菌研究过程中基础且关键的步骤即分离与培养,从分离材料、分离方法、分离部位、分离过程、培养基的选择,培养条件的筛选等方面进行综述,同时结合已分离培养成功的外生菌根菌的例子,旨在为未培养成功的外生菌根菌提供参考,以及为外生菌根菌的深入研究和资源拓展打下基础。     

莴苣原生质体的分离方法

以莴苣无菌苗的幼叶为试材,研究了不同的分离材料、质壁分离时间、苗龄、酶液组合、酶解时间及酶液渗透压等对原生质体分离效果的影响。结果表明:幼叶在含有13%甘露醇的CPW溶液里质壁分离2h,获得的原生质体产量存活率均高于其它质壁分离时间;苗龄为20d的幼叶分离得到的原生质体质量高,原生质体呈圆形、内含物多、活力强;酶液组合为1.0%纤维素酶+0.2%离析酶,25℃黑暗条件下酶解12h可获得大量有较高活力的原生质体;酶解液中添加浓度为9%的甘露醇较适合原生质体分离。     

食菌简易分离复壮法

一般说,真菌的各个部分都能分离培养出新个体。目前常采用的有孢子分离、组织分离和基内菌丝分离。孢子分离是获得优良菌株的手段,但易产生变异,需经出菇试验,性状评选等程序才能应用。组织分离和基内菌丝分离较简单易行,且能保持原有种性,因此应用较多,但需一定的技术和条件,初学者也不易掌握。我们采用以下方法进行分离、提纯、复壮,常收到较好效果,现介绍如下,供食用菌爱好者参考。     

‘赤霞珠’葡萄~(13)C和~(15)N吸收、分配特性的初步研究

以6年生果实膨大后期‘赤霞珠’葡萄为试材,运用13C和15N标记技术,分别标记不同部位和节位的枝条叶片,研究碳氮营养吸收分配规律。结果表明:标记近主干和远主干枝条叶片,叶片合成的光合产物和吸收的氮素营养在近主干和远主干枝条之间不相互转运,近主干枝条上的果实对光合产物的征调能力强于远主干枝条上的果实,δ值(表示固定的13C同化物的量)是远主干枝条上果实的4.74倍;同一枝条不同节位的标记叶片距结果部位越近,果实的δ值和Ndff值越大,说明果实优先征调距果实近的叶片碳氮素营养;副梢保留6片叶所固定的光合产物总量和吸收的氮素营养总量均大于保留2片叶的,分别是其1.1倍和1.8倍。     

小金海棠实生后代耐缺铁性状分离分析

【目的】采用直接鉴定的方法,对四倍体小金海棠(高耐缺铁,兼性无融合生殖)×山定子(不耐缺铁)杂交后代实生群体中杂种、重组型无融合生殖及非重组型无融合生殖等不同倍性的后代单株的耐缺铁性状进行评价,对筛选高耐缺铁新种质和培育抗缺铁砧木有重要的指导意义。【方法】通过观察叶片黄化情况以及测定铁含量和SPAD(土壤、作物分析仪器开发,Soil and Plant Analyzer Development)值,比较沙培-滴灌条件下小金海棠无融合生殖后代与小金海棠×山定子杂种后代的耐缺铁能力,并分析其分离情况。【结果】结果表明,小金海棠无融合生殖后代耐缺铁能力基本保持,但仍表现出与倍性相关的多样性分离;杂种后代耐缺铁能力不及无融合生殖后代,杂种后代中三倍体分离更广泛,出现耐缺铁后代比率更高;小金海棠耐缺铁性状为多基因控制的隐性性状。并筛选出若干优异的个体。【结论】小金海棠实生后代耐缺铁性状分离复杂,通过杂交育种得到兼有小金海棠与其他优良砧木品种优良性状的杂种可能性虽小却并非不可能。     

Using machine learning to identify urban forest crown bounding boxes (CBB): Exploring a new method to develop urban forest policy

Collecting and managing individual tree data is a critical activity for green sustainability strategies. Local governments are able to easily collect detailed public tree inventories, however data on trees located on private land are much more challenging and costly to collect. This means that new regulations to limit the removal of trees on private land go untested prior to their implementation, or fail to pass regulatory review processes. Without knowledge of the location of trees or the range of their different sizes, Local Government Authorities (LGAs) are unable to predict where a new policy to prohibit the removal of trees of a certain size is likely to have the greatest effect, where enforcement should be concentrated, or to convince government, the development sector and local communities of the need for action to preserve trees.The aim of this study was to explore the potential of a supervised machine learning algorithm as a cost-efficient method to understand tree sizes and locations on private land and to discuss how this information could be used for sustainable urban greening. We conclude by discussing some of the affordances of this approach to better target native vegetation protection and protect large trees; and report on the precision and recall of the detection of the urban forest.     

Effect of partial rootzone drying on growth, gas exchange, and yield of tomato (Solanum lycopersicum L.)

Three levels of partial rootzone drying (PRD) were evaluated and compared with conventional irrigation, in terms of gas exchange, water relations, growth, yield, fruit quality, and water use efficiency in tomato (Solanum lycopersicum L.) saladette-type plants growing in pots with volcanic material and drip irrigation. There were four treatments, a control, in which available water (AW) in the whole root system was allowed to fall to 90%; PRD90-30, in which on one side of the divided root AW was allowed to fall to 90% and on the other side it was allowed to fall to 30%; PRD70-30, in which on one side of the divided root AW was allowed to fall to 70% and on the other side it was allowed to fall to 30%; PRD50-30, in which on one side of the divided root AW was allowed to fall to 50% and on the other side it was allowed to fall to 30%. When each treatment reached the desired AW level they were then irrigated. At the same time, when on one side AW reached values ≤30% irrigation was shifted to the other side. Results showed a significant decrease of leaf water potential up to 14% in PRD plants compared with control. Shoot dry weight and leaf area decreased in relation to substrate available water in PRD plants. Stomatal conductance and transpiration rate were lower, up to 31 and 18%, respectively, in plants with PRD compared with control. However, CO₂ assimilation rate was similar among treatments which along with the reduction of transpiration in PRD plants, increased instantaneous water use efficiency by 28, 25, and 33% in PRD90-30, PRD70-30, and PRD50-30 treatments, respectively, compared to control. Yield, number of fruits and fruit total soluble solids content were similar among treatments. An increase of 25% in fruit titratable acidity was reached in PRD50-30. Fruit firmness increased up to 31% in PRD treatments. PRD treatments allowed a water irrigation saving up to 46%.     

Community perceptions of ecosystem services and disservices linked to urban tree plantings

The planting of trees in streets and parks is critical for urban greening efforts that seek to improve climate-change resilience in cities around the world. Ecosystem services provided by urban trees range from mitigating urban heat island effects to enhancing human well-being and conserving native biodiversity. At the same time, such tree services trade off with disservices that include risk to human safety from falling branches and infrastructure damage from root growth. Here, we performed a survey of residents of a sub-tropical region in eastern Australia to determine community perceptions of the ecosystem services and disservices linked to urban tree plantings. Our aim was to better understand the diverse perceptions of the community, prior to on-the-ground implementation of urban greening, to help guide planting programs in streets and parklands that are vulnerable to UHI effects in the region. We found strong evidence for a high level of public awareness about the beneficial ecosystem services that urban trees can provide. A broad spectrum of beneficial tree services were valued highly by the community in their urban environment including the planting of native trees that can attract and provide food for preferred wildlife; provide shade and reduce heat; allow for a strong connection with nature; have the potential to store carbon to mitigate climate change; provide a level of protection from bushfires; have aesthetically pleasing properties; and produce food for people. At the same time, however, community concerns about tree disservices were concentrated primarily on root damage to infrastructure as well as property damage and injury from falling branches. Our elicitation of community attitudes to tree services and disservices will allow for residents’ most important values and strongest concerns about trees to be explicitly taken into account when establishing a community-inclusive approach to urban tree planting.     

Effects of fragmentation on cattle in African savannas under variable precipitation

Cattle move to access patches that vary in forage quantity and quality. Fragmentation can prevent animals from reaching patches. I used an integrative ecosystem model applied to three African landscapes to explore the sensitivity of cattle populations to fragmentation (here, changes in populations as parcel areas decreased) under different precipitation patterns. I hypothesized that low and high precipitation would yield populations relatively insensitive to fragmentation, intermediate precipitation would yield more sensitive populations, and more variable inter-annual precipitation would reduce sensitivity to fragmentation. Precipitation data were altered to yield averages of 100–1,000 mm year⁻¹ and inter-annual coefficients of variation of 0–60%. A 1,000 km² landscape in each area was divided into progressively smaller parcels and simulations conducted for each parcel. Rainfall at 100 mm year⁻¹ supported low populations that were insensitive to fragmentation. Populations peaked at rainfall levels similar to those observed, and declined under higher precipitation, due in-part to shrub expansion. Fragmenting landscapes caused up to a 62% decline in cattle. High inter-annual variation in precipitation reduced sensitivity to fragmentation when precipitation was above that observed. The pattern was opposite when precipitation was below what was observed. Cattle on the landscape with fine-scale heterogeneity were relatively insensitive to fragmentation, and those on the heterogeneous but coarse-grained landscape were extremely sensitive. Fragmentation in landscapes where populations are sensitive will require more intensive inputs to offset losses, and changes in the frequency of extreme weather associated with climate change will alter the sensitivity of some populations to fragmentation. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Barriers to community garden success: Demonstrating framework for expert consensus to inform policy and practice

Community gardens receive much attention for the benefits offered to participants and their communities. However, research has documented a variety of barriers and challenges that community gardeners and support organizations face in establishing and maintaining gardens. These issues may dilute service providers’ impact, by reducing their attention to the more pressing factors that result in garden failure. Additionally, access to resources to mitigate these challenges and barriers differ from region to region. This demonstrates a significant need to identify the most pervasive barriers, challenges and obstacles in order to refine the focus of support programs and provide concentrated efforts to better position community gardens for success. The purpose of the study was to demonstrate the use of a framework to inform the development of policies and programs that stakeholders, including Extension, can adopt for overcoming the most frustrating impediments to success. It did so by using an underused but appropriately matched tool, the Delphi technique, which can easily be adopted by community garden stakeholders. Because the types of stakeholders are diverse and challenges are complex, the objectives were to determine whether consensus could be achieved and whether a core set of barriers exist. The group agreed upon four barriers, with the highest level of agreement centering on the challenge of time demand for community engagement.     

探究湖北省城市水生态景观设计方法

如何合理有效的建立水生态景观?如何改造以往固化而发臭的河道与过水区、修复退化的生态湖泊与湿地并设计出行之有效的生态水域景观改良方式方法?如何根据自身环境的不同,将人与水环境、人的亲水性相结合,构建更绿色的城市水景,打造和谐的人居环境,是摆在环艺工作者面前最现实、最紧迫的课题。     

Habitat factors related to wild rabbit conservation in an agricultural landscape

Populations of European wild rabbit (Oryctolagus cuniculus) have been decreasing since the 1950s. Changes in agricultural practices have been suggested as reasons for their decline in Mediterranean landscapes. We evaluated the environmental variables affecting rabbit distribution in a semiarid agricultural landscape of Northeastern Spain. Sampling was performed in 147 sites randomly distributed across Zaragoza province. At each site, data were recorded in five 100 m segments along a 1 km transect, following ecotones between crops and natural-vegetation areas. A rabbit abundance index was estimated from latrine count, pellet density and number of plots with pellets. In addition to environmental variables that have been shown to be related to rabbit abundance in other habitats, as climate, soil hardness and topography of the site, we measured landscape components related to agricultural use, such as structure of natural vegetation in remaining areas non-devoted to agricultural use and distances to different types of crops and to ecotone between crop and natural vegetation. Our results showed that rabbit abundance was positively correlated to yearly mean temperature, February and May mean rainfall, and negatively correlated to September and November mean rainfall, hardness of soil, and site topography. In relation to agricultural use, rabbit abundance was positively correlated to the scrub structure of natural-vegetation areas and negatively correlated to distance to edge between cultivated unirrigated cereal crops (wheat or barley) and yearly resting cereal crops. Rabbit abundance increased only when the edge between alternate cereal crops was less than 50 m from the ecotone between crops and natural vegetation.This revised version was published online in May 2005 with corrections to the Cover Date.     

Ecological functions and human benefits of urban forests

The recent sprawl of urbanization in the Eastern U.S. perpetuated by population growth and economic success has caused landscapes to become vulnerable to degradation. As urban development encroaches on such landscapes, various anthropogenic stressors are introduced including air pollution, land conversion, and alterations in watershed hydrology. Across various disciplines, urban forests have been presented as a method to ameliorate human and environmental health in metropolitan environments. Understanding how to incorporate urban forestry into city design is critical and urban planners would benefit from a review that holistically describes the diverse set of services urban forests have to offer. We conducted a review to highlight the ecological functions and human benefits of urban forests and to identify gaps in the literature. We synthesized the findings of research studies in the last 20 years to illuminate the human, abiotic, and biotic services of urban forestry. As environmental quality is rapidly deteriorating in anthropogenic environments, our findings suggest city planners should consider trees as a method of mitigation to alleviate these impacts. Ultimately, when managing urban forests, an interdisciplinary approach involving all levels of governance is necessary to ensure the maximum potential of urban trees. Through this study, the consolidated research can aid in sustainable development and innovation to combat the anthropogenic stressors associated with the sprawl of urbanization.