Ancient tripartite coevolution in the attine ant-microbe symbiosis

The symbiosis between fungus-growing ants and the fungi they cultivate for food has been shaped by 50 million years of coevolution. Phylogenetic analyses indicate that this long coevolutionary history includes a third symbiont lineage: specialized microfungal parasites of the ants' fungus gardens. At ancient levels, the phylogenies of the three symbionts are perfectly congruent, revealing that the ant-microbe symbiosis is the product of tripartite coevolution between the farming ants, their cultivars, and the garden parasites. At recent phylogenetic levels, coevolution has been punctuated by occasional host-switching by the parasite, thus intensifying continuous coadaptation between symbionts in a tripartite arms race.     

Fungus-growing ants

Fungus-growing ants (Attini) are in reality unique fungus-culturing insects.There are several hundred species in some dozen genera, of which Acromyrmex and Atta are the conspicuous leaf-cutters. The center of their activities is the fungus garden, which is also the site of the queen and brood. The garden, in most species, is made from fresh green leaves or other vegetal material. The ants forage for this, forming distinct trails to the vegetation that is being harvested. The cut leaves or other substrate are brought into the nest and prepared for the fungus. Fresh leaves and flowers are cut into pieces a millimeter or two in diameter; the ants form them into a pulpy mass by pinching them with the mandibles and adding saliva. Anal droplets are deposited on the pieces, which are then forced into place in the garden. Planting of the fungus is accomplished by an ant's picking up tufts of the adjacent mycelium and dotting the surface of the new substrate with it. The combination of salivary and anal secretions, together with the constant care given by the ants, facilitates the growth of the ant fungus only, despite constant possibilities for contamination. When the ants are removed, alien fungi and other organisms flourish. A mature nest of Atta Sexdens may consist of 2000 chambers, some temporarily empty, some with refuse, and the remainder with fungus gardens. Thousands of kilograms of fresh leaves will have been used. A young laboratory colony of Atta cephalotes will use 1 kilogram of fresh leaves for one garden. The attines are the chief agents for introducing organic matter into the soil in tropical rain forests; this matter becomes the nucleus for a host of other organisms, including nematodes and arthropods, after it is discarded by the ants. One ant species cultures a yeast; all others grow a mycelium. In the higher species the mycelium forms clusters of inflated hyphae. Mycologists accept as valid two names for confirmed fruiting stages: Leucocoprinus ( or Leucoagaricus) gongylophora (Moeller 1893) and Lepiota n. sp.     

Territoriality and the origin of slave raiding in leptothoracine ants

The slave-raiding behavior of Harpagoxenus canadensis closely resembles the territorial behavior of its host species, Leptothorax muscorum. Of primary importance is the discovery that both species of ants recruit nest mates into battle using an alarm-recruitment system which is a probable evolutionary precursor of more specialized forms of slave-raiding recruitment. The behavior of these species supports the hypothesis that slave raiding in leptothoracine ants evolved from territorial behavior.     

梅花大树移植技术初探

2009至2010年,武汉东湖从全国各地搜集移植大梅花树169株,建立了"古梅园"。经过科学管理和精心养护,目前成活率达到98%。本文以东湖古梅园为例,对梅花的大树移植技术进行了初步研究,总结出了梅花大树的选择原则、带土球移植的关键技术措施、移植地的准备和移植后的管理措施,以及提高移植成活率的方法和注意事项。     

野生古茶树茶与茶园茶的比较研究

采用感官审评和化学分析手段,对野生古茶树茶和茶园茶的外形、颜色、滋味、香气等进行审评、测定和比较。两者都为条索,在颜色方面,野生古茶树茶的干品偏向红黄,汤色黄红,茶园茶的干品呈绿黑,茶汤绿黄色;滋味方面,野生古茶树茶苦涩味较淡,醇和,回甘,茶园茶苦涩味比之更盛,味微短,入口略甜。茶多酚、黄酮类化合物两者基本一样,分别是28.9%左右和7%左右,测定的5种儿茶素,茶园茶是野生古茶树茶的两倍多,咖啡碱茶园茶是野生古茶树茶的约两倍,游离氨基酸野生古茶树茶比茶园茶高,可溶性糖野生古茶树茶(3.82%)比茶园茶(4.60%)低;在香气化合物方面,野生古茶树茶测出定名的香气化合物有58个,茶园茶有74个,两者相同的香气化合物有12个。野生古茶树茶泡饮比茶园茶优越很多,儿茶素类、香气化合物对人体的作用有待进一步研究。     

Parasitoids as selective agents in the symbiosis between lycaenid butterfly larvae and ants

The larvae of Glaucopsyche lygdamus (Lepidoptera: Lycaenidae) secrete substances that attract ants. In two field sites in Colorado, tending ants protect caterpillars of G. lygdamus from attack by braconid and tachinid parasitoids. This protection may have been an important feature in the evolution of the association between lycaenid larvae and ants.     

Postsecretory hydrolysis of nectar sucrose and specialization in ant/plant mutualism

Obligate Acacia ant plants house mutualistic ants as a defense mechanism and provide them with extrafloral nectar (EFN). Ant/plant mutualisms are widespread, but little is known about the biochemical basis of their species specificity. Despite its importance in these and other plant/animal interactions, little attention has been paid to the control of the chemical composition of nectar. We found high invertase (sucrose-cleaving) activity in Acacia EFN, which thus contained no sucrose. Sucrose, a disaccharide common in other EFNs, usually attracts nonsymbiotic ants. The EFN of the ant acacias was therefore unattractive to such ants. The Pseudomyrmex ants that are specialized to live on Acacia had almost no invertase activity in their digestive tracts and preferred sucrose-free EFN. Our results demonstrate postsecretory regulation of the carbohydrate composition of nectar.     

园林木材及其在园林木建筑中的应用

在了解木材特性的基础上，提出了木材在园林景观中的重要作用。简要介绍了木材在古代和现代园林景观中的应用情况，并根据国内外的研究现状，分析了园林木材今后的发展趋势。     

园林工程技术专业课程群建设的生态分析——以四川省区域环境为例

用生态学理论和方法对高等职业教育园林工程技术专业课程群和教育环境之间的关系以及课程相互之间的关系进行了分析,结合四川省园林工程技术企业需求所组成的教育区域环境空间异质性,用生态后现代主义的观点讨论了园林工程技术专业的课程建设,绘出该专业课程的生态网有向结构,揭示了园林工程技术专业课程群之间的动态关系.     

中国早期园林的农业功能及其现实意义——以西汉皇家苑囿为例

西汉苑囿因其所属历史时期的特殊性，成为中国古典园林生成期的巅峰之作。本文首先说明苑囿这种早期园林形式的特征，然后以西汉皇家苑囿为例，分析其农业生产功能和农业试验功能，最后提出，另一种园林与农业关系密切的形式是现代农业观光园，认为观光农业建设可以从早期园林中汲取营养。     

论中国古代园林建筑之门的文化

以中国古代园林建筑中的门为研究对象,对其起源、种类和形制进行了较全面的阐述,从中探究中国古代园林建筑中的门所内含的中国传统建筑文化,呼吁现代建筑创作应关注传统。     

禅宗园林植物配置分析

禅宗既是一门直指人心、见性成佛的中国化佛学,又是一门探索宇宙身心、透彻人类心性的哲学。从禅宗的传入至鼎盛,其在古代哲学、文学、艺术、科学等方面都起着十分重要的作用。禅宗园林,虽源于中国,但成熟于日本。尤其是最具日本特色的“枯山水园林”和“露地庭”深深浸润着禅宗思想。与此同时,相适应的植物景观以古朴、简约的形式来表现自然景观。分析禅宗园林的植物景观,有助于人们在物质资源锐减的今天寻求新的园林发展空间。     

寒地城市生态园林树种组合的植物群落关联性分析

寒地城市因其气候的特殊性,树种之间的关联性较为特殊。以黑龙江省为例,调查常见园林树种的病虫害,并对树种抗病虫害能力进行分析。运用2 统计量、联结系数分析树种种间关联性;根据相同树种间的负密度制约效应,对树种种内关联性进行研究;结合树种的抗病力得出3组关联性较好的树种,可作为生态园林的基础植物群落。在关联性研究的基础上,对树种的最适多度进行研究,得到2种具有明显优势的树种白桦Betula platyphylla和水曲柳Fraxinus mandschurica,可作为黑龙江省生态园林的骨干树种。图2表7参22     

浅析中国古典园林中的生态智慧

古人对生态的尊重与保护思想是根深蒂固的,是融入到传统文化中的,是在中国锦绣 河山和主流哲学思想的影响下自然形成的。本文根据古人兴造园林的理论和园林实例窥见中 国古典园林中的生态智慧。     

杭州植物园木兰山茶园现状分析及改造方案初探

山茶为我国十大传统名花之一,是重要的园林观赏植物。山茶园是搜集、保存山茶资源,展示山茶多样性和景观的植物专类园。现对我国较早建立的杭州植物园木兰山茶园进行了现状分析,并提出了改造方案,包括园林基础设施的改造,丰富、完善植物景观和木兰山茶园文化内涵的提升,为其它同类专类园的建设提供了借鉴。     

西双版纳布朗族古茶园传统知识调查

运用民族植物学原理,采用野外面上调查、定点社区入户调查和文献研究相结合的方法,调查了西双版纳地区布朗族认知、管理、利用与保护古茶园的传统知识和经验.结果显示:在1700年前,布朗族就以原始宗教信仰为基础,逐渐形成对茶树种植的禁忌崇拜,通过"习惯法"、"头人"等来规范古茶树的种植与管理,形成了一套具有一定科学意义的古茶树种植系统,并演绎出丰富的传统制茶方法和饮茶习俗,形成独特的古茶树资源保护与利用的传统文化知识,如布朗族对茶的传统习惯用法、医药用法等.本文在对布胡族古茶园传统知识调查的基础上,分析古茶园传统知识遗忘丢失的原因,提出古茶园传统知识保护建议.     

苏州古典园林古树名木的现状及生态景观分析

针对苏州古典园林独特的地域特色与环境,认为古树名木不仅是一种生物个体或自然资源,更是历史的见证者和记忆者,具有独特的人文资源属性和价值,在此基础上对苏州古典园林古树名木的现状及其生态景观加以分析,阐释了古树名木的含义,并参照相关条例界定了古树名木的级别,以入选世界文化遗产的苏州拙政园、留园、网师园、环秀山庄、沧浪亭、狮子林、艺圃、耦园以及怡园9个古典园林的古树名木为调查对象,在2002年相关调查数据的基础上,对古树名木进行重新调查、核实,得知古树名木较2002年减少了11株。具体介绍了白皮松、银杏、圆柏、黄杨、柘树等的栽种历史与生长状况,强调了适地适树对百年以上古老树木生长的重要性,强调园林保护工作也应重视对植物的研究工作。     

地域语境下的衙署园林场所特征探析——以罨画池为例

以四川省成都市西部的罨画池为例,以之作为西蜀园林中衙署园林的典范,从山水布局、园林建筑、植物环境以及园林品题方面,对罨画池的造园特征加以分析,提炼并总结出罨画池在西蜀地域语境下所体现的衙署园林的场所特征,认为罨画池作为衙署园林的典型代表,印证了中国古代衙署园林引水造园,因水得景的特征。以期为今后的地区园林创作提供借鉴。     

唐代园林特征与西安城市规划建设

以在中国园林发展史中占有重要历史地位的唐代园林为例,尝试从文化特征、生态特征和规划特征3个方面描述唐代园林特征,探索唐代园林文化的发展踪迹,思考西安城市规划建设中的相关问题,提出古城保护中的文化建设、生态建设、规划建设的对策与建议。