Biology of the Epacridaceae

No abstract     

Pectic Zymograms and Water Stress Tolerance of Endophytic Fungi Isolated from Western Australian Heaths (Epacridaceae)

Forty-nine isolates of root-inhabiting fungi were obtained fromthirteen species of eleven genera of native Epacridaceae andcompared in relation to host taxonomy and habitat of origin.Pectic zymograms of extracts of the cultured endophytes showeda marked degree of homogeneity of banding patterns amongst isolatesfrom a mesic wetland site, whereas those from dryland habitatdisplayed more heterogenous banding. It is speculated that hostspecies can operate with only a limited number of fungal associatesunder mesic conditions but require a higher degree of endophytevariation when combating dry and impoverished environments.Considerable distinction between the geographically diverseendophytes isolated from the common hostLysinema ciliatum suggestedthat selection of endophytes was not driven primarily by hosttaxonomy. Ascribing functional significance to the observed differencesbetween endophytes was studied by examining responses of culturedisolates to polyethylene glycol induced-water stress coveringa range of potentials from -0.16 to -2.96MPa. Three responsetypes were observed: (a) the isolate produced minimal radialgrowth at all water potentials tested, (b) maximum growth ofthe isolate occurred under least water stress, with progressivesuppression of radial extension with decreasing water potentialand (c) maximum growth of the isolate occurred under a degreeof water stress. The broad range of responses to water stressobserved was suggested to reflect the diverse habitat tolerancedisplayed by epacrids and their endophytic partners in southwest Australia. ericoid mycorrhizas; pectic zymogram; water stress; Epacridaceae     

保护生物学、保护生态学与生物多样性科学

正在查阅生物多样性方面的文献时,经常会遇到3个学科,即保护生物学、保护生态学和生物多样性科学。三者的关系如何?各自具有怎样的特点和发展过程?为了更好地理解3个学科的产生背景和特点,需要回顾一下始于19世纪中叶的保护运动     

Phytogeography, range size and richness of Australian endemic Sauropus (Euphorbiaceae)

Aim To investigate the distribution of Australian species of Sauropus. The information obtained is used to (1) identify areas of highest richness and centres of endemism, (2) investigate latitudinal gradients of richness and range size, (3) determine the types of rarity shown, and (4) provide hypotheses on historical biogeography of the genus within Australia. Location Australia. Methods Specimens from 17 herbaria and field searches were examined and label and field information collated on distribution, habit and habitat. Distribution information was used to map all species within 784 grid cells of 1° × 1° and within the 97 Australian ‘ecological regions’. Morphometric cluster analysis of species was conducted using Kulczynski association and flexible UPGMA on 23 character states. Simple regression was used to correlate species richness, density and range size to changes in latitude. CLIMEX is used to match the climate of the region of highest richness in Australia with other areas of the world. Results Species richness was highest within the tropical north of Australia, and most species were associated with tropical savanna woodlands. Two areas were identified as centres of endemism and these corresponded closely to areas of high species richness. Four morphological groups were identified. One species (Sauropus trachyspermus) was found to be widespread, however all other species had small geographical ranges. Species richness and range size were significantly correlated with changes in latitude. Ten species were found to be of the rarest type, warranting conservation initiatives. Main conclusions Two regions of high richness and endemism of Sauropus occur, Thailand and Australia. Within Australia, the Kakadu‐Alligator River and the Cairns‐Townsville areas were identified as centres of endemism and high species richness for Sauropus. Australian Sauropus in general occur in similar communities and climates as other members of the genus elsewhere. Ten of the 27 species of Australian endemic Sauropus are extremely rare and warrant conservation initiatives. Correlations of latitude to species richness are potentially due to Sauropus radiating from the climatically stable top end of Australia. Increasing range size in more southern latitudes may also be due to stability of climates in the top end or because there is more available land area at these latitudes. Sauropus micranthus, the only non‐endemic species, is probably a more recent invader from the Tertiary period when tropical rain forests where more extensive and congruent with those of New Guinea.     

Relationships Between Fire Response, Morphology, Root Anatomy and Starch Distribution in South-west Australian Epacridaceae

Selected epacrids (92 species in 15 genera) were examined withrespect to fire response type, morphology, root anatomy andstarch storage. Seeders, 75% of the species investigated, possesseda single main stem and a small root system with lateral rootswhich in most cases did not spread beyond the shoot canopy.Resprouter species were generally multi-stemmed with large lignotuberousroot stocks. Certain seeder and resprouter species were intermediatein form and showed small root systems and basally branched mainstems. Amounts of starch in roots of seeders (1.9±0.5mgstarch gd.wt per root) were much less than in resprouters (14.1±3.3)whereas amounts in shoots were similar (1.9±0.5 and 1.6±0.6mgstarch gd.wt per shoot, respectively). Starch storage in rootswas mostly confined to rays of xylem parenchyma and inter-rayxylem parenchyma and the greater storage capacity of resprouterswas generally due to broader rays. Growth zones in root xylemranged from clear, verifiable annual rings, as in many seederspecies, to indistinct growth zones, typical of many resprouterspecies. Shoot:root dry weight ratios were higher in seedersthan resprouters. The study suggests that speciation withinthe Epacridaceae into seeder and resprouter forms involved divergentdifferentiation in terms of morphology, shoot:root dry weightratio root storage of starch. Seeder; starch storage; growth rings; growth zones; south-west Australia; resprouter; Epacridaceae     

Response of mycorrhizal seedlings of SW Australian sandplain Epacridaceae to added nitrogen and phosphorus

The responses of seedlings of four species of southwestern Australiansandplain Epacridaceae to added phosphate (P), added NH₄N0₃(N) or Complete nutrients were studied in glasshouse pot cultureusing cores of habitat soil as rooting substrate. Positive responsesto N and Complete nutrients were evident for three species interms of shoot height and shoot dry weight in comparison withControl plants supplied only with deionized water, but no speciesresponded significantly in its shoot growth to P. Root dry weightwas generally less in Complete and N treatments compared toP and Control, leading to considerably higher shoot: root ratiosin the former two treatments. There was no effect of treatmenton infection intensity of hair roots. Root xylem sap compositionshowed greatly elevated levels of nitrogen in the Complete andN treatments and of phosphate in the P treatment. Ammonium comprisedthe major nitrogenous solute of xylem in Control and P treatmentswhile nitrate levels exceeded ammonium in Complete and N treatments.Glutamine levels were particularly high in the P treatments.Labelling of the Complete or N treatments with ¹⁵NH₃ or ¹⁵NO₃(supplied as single labelled ammonium nitrate) indicated thatboth forms of N were taken up and incorporated into plant insolubleN. Key words: Epacridaceae, nitrogen, phosphorus, mycorrhiza, south-west Western Australia     

保护行为学: 正在兴起的保护生物学分支学科

过去的30年里, 人们利用动物行为的进化生物学方法来解决保护实践中遇到的问题, 行为学、行为生态学与保护生物学相结合, 产生了保护生物学的一个新分支学科--保护行为学。保护行为学的研究目的是: 从物种保护实践中发现环境对动物行为的影响以及行为的生态适应性, 并把动物行为学和行为生态学理论应用到物种保护实践中, 从而促进物种保护工作。目前全球有10%的物种濒临灭绝, 生物多样性保护日趋紧迫, 保护行为学的诞生为行为学和保护生物学研究带来了新的机遇, 也表明行为学家和保护生物学家正在担负起挽救濒危物种的使命。不久的将来, 保护行为学及其相关学科将更加繁荣。     

Primate Conservation Biology

Primate Conservation Biology. Guy Cowlishaw and Robin Dunbar. Chicago: University of Chicago Press, 2000. 498 pp.     

Cytoevolution, Phylogeny and Taxonomy in Epacridaceae

Chromosome numbers in Epacridaceae were collated from variousauthors and superimposed on to recent cladograms for the family.The results strongly indicate that reduction in chromosome numberoccurs with evolutionary advancement. Thus Epacridaceae, incommon with ‘Ericaceaesens. strict .’ and ‘Vacciniaceaesens.strict. ’, has evolved from a primitive karyotype of atleastx =12 and probablyx =13. This conclusion dispels earlierpaleopolyploid models based on a primitivex =6 in the family.Other aspects of cytoevolution, such as chromosome number asa generic character especially in cytologically advanced generaof the Styphelieae, are discussed. Cytoevolution; cladistic models; primitive character states for chromosome number; dysploid falls; cytotaxonomy; Epacridaceae; Richeoideae; Epacridoideae; Epacrideae; Styphelieae; Ericaceae     

保护生物学的现状、挑战和对策

现代社会中的重大环境热点问题研究推动了保护生物学的发展。学科融合使得保护生物学正在发展成为保护科学(Conservation Science)。保护生物学需要广泛参与, 然而, 根据Google Search Volume, 中国互联网用户对保护生物学与生物多样性概念的兴趣不高。全球生物多样性的主要部分在发展中国家, 研究发现主要保护生物学项目或最活跃的研究工作在发展中国家进行。然而科技投入不足限制了发展中国家保护生物学论文的产出。到目前为止, 中国作者(含在华工作的外国作者)在ISI Web of Knowledge数据库中保护生物学主流刊物上发表的论文数量少, 与中国的生物多样性占全球的比例不相称。保护生物学研究面临一系列的挑战: (1)保护生物学研究因过分强调价值与实用而受到了批评; (2)保护生物学缺少机理探讨、缺少实验、缺少对比研究, 还没有形成完整的理论体系; (3)保护生物学是一门涉及空间尺度的学科, 不同局部、不同空间尺度的保护生物学问题往往缺乏可比性; (4)许多保护生物学数据没有正式发表, 这些“灰色文献”限制了保护生物学的发展; (5)与生物多样性有关的国际法和国内法的制定和实施为保护生物学带来了新的发展机遇。我们提出如下对策: (1)明确保护生物学的价值取向; (2)建立保护生物学研究方法和理论体系; (3)重视和探讨保护生物学的空间尺度问题; (4)充分收集利用“灰色”数据和文献, 建立与发表在同行评议科学刊物上的文献库相对应的初级生物多样性网络数据库, 促进保护生物学的荟萃分析和大研究; (5)积极围绕生物多样性有关的国际法开展相关研究。保护生物学这一门大科学的完善离不开各国保护生物学的深入研究, 部分中国学术期刊用英文发稿, 是中国保护生物学工作者研究汇入世界主流的途径之一。