ULTRASTRUCTURAL ASPECTS OF TWO SPECIES OF GUTTULINOPSIS

Two acrasid cellular slime molds. Guttulinopsis vulgaris and G. nivea, are compared at the ultrastructural level. The amoebae of the two species are indistinguishable except for the presence of intranuclear fibers in G. vulgaris. Both species share some unusual features, including: plate-like cristae in the mitochondria, production of microbody-like organelles in the perinuclear space, spores with thin bilaminar walls, and stalks containing microfilaments bound in striated bundles. These and other observations are discussed with regard to the development of the sorocarps and the relationship of the genus to other members of the Acrasida.     

REPRODUCTIVE BIOLOGY OF THE CERRO CUADRADO (JURASSIC) FOSSIL CONIFERS: PARARAUCARIA PATAGONICA

Seventy-two silicified cone specimens of Pararaucaria patagonica Wieland from the Cerro Cuadrado (Jurassic) petrified forest in Patagonia were studied by use of thin sections and reflected light. Traces from the cone axis stele to the bract and ovuliferous scale are separate at their origins. In cross section the abaxially concave ovuliferous scale trace and massive circular bract trace branch half-way out into the cone-scale complex. Two triangular-shaped bundles of fibers follow the scale trace into the laminar part of the ovuliferous scale. Both surfaces of the ovuliferous scale possess hairs which may have assisted in cone closure. Cones typically contain one flattened, winged seed per ovuliferous scale. Multi-layered seed integuments are represented by an inner fleshy layer of large cells filled with a black amorphous material, a sclerotesta consisting of wedges or fan-shaped groups of sclereids oriented at right angles to the seed surface, and a thin, often crushed fleshy layer. Seed wings consist of anastomosing, branched cells resembling glandular hairs and containing many intercellular spaces. Well-preserved polycotyledonous embryos containing up to eight cotyledons are present in several cones. Tissues of the embryo including the shoot apex, calyptroperiblem, hypocotyl, and cotyledons are described. On the basis of anatomical and morphological features, specimens of P. patagonica are compared to members of both extant and extinct families of conifers including the Araucariaceae, Taxodiaceae, Pinaceae, Cupressaceae, and Cheirolepidaceae.     

中国北方新发现的大角鹿化石

本文对两件大角鹿新材料做了描述、定种,同时对更新世大角鹿的系统发育关系和地理分布做了讨论。     

ASCOCARPIC CENTRUM ONTOGENY OF SPECIES OF HYPODERMATACEAE OF CONIFERS

Studies on the morphology of the ascocarps of 39 species of Hypodermataceae revealed several previously unknown cytological features. Two basic and one intermediate type of centrum ontogeny are discussed. Ascal initiation within Type I centrum occurs in the basal cells of the pseudoparaphyses and involves anastomoses, while ascal initiation within Type II occurs in cells of a plectenchymatous centrum, with no visible anastomosing in the ascocarp. There is frequent anastomosing between vegetative hyphae well in advance of initiation of the ascocarp. Ascal initiation in the intermediate type has ontogenetic sequences similar to those in Types I and II.     

ASCOCARPIC CENTRUM ONTOGENY OF SPECIES OF HYPODERMATACEAE OF CONIFERS. II

Ascocarpic studies of the ontogeny of Lophodermium nitens disclosed a type of development unlike that of all other species of Hypodermataceae occurring on conifer needles. For this reason the centrum of L. nitens is designated as Type III and is compared with Type I (Gordon, 1966). Because L. nitens produces its ascocarp in several tissues of various species of pine, the ontogeny of ascocarps in different locations is discussed and illustrated. The most significant ontogenetic feature of the ascocarp of L. nitens is a layer of hyaline cells in the primordium; this layer is meristematic and gives rise to all subsequent structures of the centrum.     

CARE OF THE NEGLECTED BURN PATIENT

In spite of widely dispersed modern knowledge of burn treatment, neglect or inept care of severely burned patients continues as a cause of a considerable medical problem. Since the neglected patient is usually emaciated, pain-ridden and low in morale, prompt attention to rehabilitation through blood transfusions, nourishment, relief of pain and cleansing of the wound is mandatory. Skin grafting as soon as possible is the aim.     

木兰科的化石记录

通过整理和分析木兰科植物的化石记录发现：不论是植物大化石还是花粉,迄今为止在白垩纪以前地层中尚无可靠的记录,自白垩纪以来,木兰科的许多种广泛发生于北半球,如亚洲,欧洲及北美等地,但非洲和大洋洲至今尚未发现木兰科的化石记录。该科最早的化石记录为中国东北延吉地区早白垩世大拉子组的喙柱始木兰Archimagnolia rostrato-stylose Tao et Zhang. 根据现有化石记录,并结合木兰科现代植物的地理分布,推测：1）木兰科的起源时间不迟于早白垩世Aptian-Albian期;2）木兰科起源地点可能是东亚,后来经过欧洲进入北美,再从北美迁移到达南美洲;3）在地质历史时期,木兰属的出现比鹅掌楸属早,从而支持根据形态学与分子系统学研究得出的木兰属较鹅掌楸属原始的结论。     

完全树构建中的关键领域:rRNA 序列与超级树

20年来,分子系统学在理论和实践方面都有飞速的发展.随着可用分子标记和所涉及阶元数量的增多和范围的扩大,以及计算能力的进步,人们对完全树(universal tree)将地球上所有物种囊括在内、描述其间的亲缘关系的系统发育树的憧憬正在逐步成为现实.由于rDNA/rRNA是惟一作为所有细胞生命形式所共有的分子标记,其在构建完全树的过程中具有不可替代的作用.近5年,超级树(supertree)的技术逐步完善,已经在若干类群中有良好的应用,形成了系统发育与进化生物学领域的研究前沿之一,为最终获得完全树奠定了坚实的基础.