Identification of a mycorrhizal fungus in the roots of achlorophyllous Sciaphila tosaensis Makino (Triuridaceae)

The identity of a mycorrhizal fungus in the roots of achlorophyllous Sciaphila tosaensis was investigated by DNA analysis and examination of the morphology of the association. The morphological features of the mycorrhizal fungus, i. e. aseptate hyphal coils, vesicles, arbuscule-like branching, and degenerate coils were similar to those previously reported for other achlorophyllous plants. Spore-like propagules identified asa glomalean fungus were propagated from root pieces of S. tosaensis in pot culture using alfalfa as the host trap plant. A PCR product was obtained from colonized root of S. tosaensis using the taxon-specific primers, VANS1 and VAGLO. Sequence analysis of the DNA fragment showed it to be almost identical to other Glomus species. Although it has been reported many times that the morphology of mycorrhizal fungi in achlorophyllous plants is quite similar to that of arbuscular mycorrhizal fungi, this is the first report of the isolation and identification of such a fungus itself.     

A dorsiventral mycorrhizal root in the achlorophyllous<Emphasis Type="Italic"> Sciaphila polygyna</Emphasis> (Triuridaceae)

The star-like root system of the achlorophyllous Sciaphila polygyna (Triuridaceae) consists of roots up to 1.4 mm thick and 1 cm long seemingly radiating from a single origin. Internally, the roots show a bilateral symmetry when viewed in cross-section: the third root cell layer contains rather loose coils of the aseptate mycorrhizal fungus from the dorsal to the lateral sides, in contrast to the extremely dense coils of thin hyphae in its ventral part. Additionally, the hyphae develop vesicle-like swellings mainly in the central part of the dorsal side as well as the lateral parts of the third layer. The fourth root layer is anatomically heteromorphic, having exceptionally large cells, reaching up to 320×130 m in size (giant cells), in the lower lateral parts. The root-colonizing hyphae only degenerate in the fourth layer, most readily in the giant cells, where they may swell to 24 m in diameter, collapse and end as amorphous clumps. Hyphae in the third layer keep their definite structure. The structures are interpreted to be the result of a dynamic reaction of the root to the actual fungal penetration points in order to maximize the benefit from the subsequent colonization by compartmentation of the root tissue. The function of the third layer is to host the fungus and keep it alive within its cells, while mainly the giant cells serve for its digestion. Many indications suggest an arbuscular mycorrhiza for this association. Similarities and differences to other myco-heterotrophic species are discussed.     

Arbuscular mycorrhizal fungi in roots of non-photosynthetic plants, <Emphasis Type="Italic">Sciaphila japonica</Emphasis> and <Emphasis Type="Italic">Sciaphila tosaensis</Emphasis> (Triuridaceae)

The mycorrhizal fungi in the roots of achlorophyllous Sciaphila japonica and S. tosaensis (Triuridaceae) were identified by molecular methods. The habitats of S. japonica were in a tree plantation of Japanese cypress, Chamaecyparis obtusa, and bamboo forests, and those of S. tosaensis were in a camellia forest and a bamboo forest. In the root cortical cells of both plants, aseptate hyphal coils were observed, which suggested the Paris-type arbuscular mycorrhiza (AM). A phylogenetic analysis based on a partial sequence of an AM fungal nuclear small subunit ribosomal RNA gene showed that the fungal DNA sequences of S. japonica were separated into three closely related clades. Those of S. tosaensis were separated into two clades, which were also closely related to each other. The AM fungi of S. japonica and S. tosaensis were completely separated in the phylogenetic tree even among those found in the same habitat, which suggests the high specificities in the plant-fungal partnerships. All the detected AM fungi in these plants belonged to Glomus-group A. Even though the habitats are in quite common environments, both plant species are known as endangered species in Japan. Such a definite specificity in AM symbioses seems to restrict the distribution of the myco-heterotrophic plants.     

In vitro asymbiotic germination and seedling development of Limodorum abortivum (Orchidaceae)

Abstract

Germination tests were carried out using immature seeds of Limodorum abortivum and applying in vitro techniques. The results proved that BM₁ culture medium is suitable to promote both germination and further growth stages. Details of the developmental pattern, and some micromorphological features, are described.     

Root architecture,early development and basal sweep in containerized and bare-rooted Douglas fir (Pseudotsuga menziesii)

Seedlings grown in containers often have deformed, spiralling, kinking root systems (reported especially in pine growing in colder climates like Fenno-Scandinavia). The current study examines the effect of containers on the root systems of Douglas fir planted in Ireland. A sample of sixteen 10-year-old Douglas fir trees, planted as either bare-rooted transplants (2/1) or containerized seedlings (Paperpot 610 (2/0)) on an acid brown earth site in Ireland, were excavated for root achitectural studies. In addition to thorough above-ground measurements, an assessment of basal sweep was also carried out. Root systems were systematically described and horizontal angles, cross-sectional areas (CSA), and maximum depths of all roots>5 mm in diameter were recorded. Various biomass ratios and estimates for dominant roots were also calculated. Symmetry of the root systems, max. and min. numbers, and CSA of roots for sectors of various sizes were compared for the two plant types. The initially (when planted) bigger bare-rooted transplants were still larger than the container-planted trees after ten years. Of the total above-ground fresh weight, the container stock had allocated more to the crown and less to the stem compared to bare-roots. The difference in root weights between stock types was small. Basal sweep occurred on average in 50% of the bare-roots and 35% of the container trees. The direction of the basal sweep leaning was concentrated to the NE, which coincided with the direction of the slope and the prevailing wind direction. No effect of planting position in relation to the direction of site preparation was found for basal sweep. The size of the root system, fresh weight and total cross-sectional area was on average for all trees correlated to both DBH and shoot fresh weights. For containers separately, however, only root area was correlated to DBH and stem fresh weight. In spite of the difference in the above-ground size, there were no significant differences in root numbers and root area (CSA) between the two plant types. No difference in rooting depth between plant types was found. When splitting the root system into 120° horizontal sectors (1/3 of the root system) the highest numbers of roots were concentrated in the NW direction. The highest amount of root area tended to be concentrated along a NW-SE diagonal, with a dominance for the latter (SE). Sectors without dominant roots (expected to be the future main structural, stabilizing roots), varied in size (94–178°) but were on average wider in bare-roots and on average concentrated in the NE direction and the downhill side of the slope. This revised version was published online in June 2006 with corrections to the Cover Date.     

Architecture and development of the oil-palm (Elaeis guineensis Jacq.) root system

The growth dynamics and architecture of the oil-palm root system are described. Following a transitional juvenile phase, eight different morphological types of roots have been distinguished according to their development pattern and state of differentiation: primary vertical and horizontal roots, secondary horizontal roots, upward growing secondary vertical roots and downward growing secondary vertical roots, superficial and deep tertiary roots and quaternary roots. The relative position of these types of roots determines a morphological and functional unit of the root system called 'root architectural unit' of the oil palm. This root polymorphism enabled us to define a morphogenetic gradient, which reflected the oil-palm root-system ontogenesis.     

磷空间有效性对拟南芥根形态构型的影响

磷空间有效性显著影响拟南芥主、侧根生长。在均一的磷处理下,极度磷胁迫或过量供磷均会导致拟南芥主根变短和侧根密度降低。在分层的磷处理下,上层高磷下层低磷能明显促进主根伸长生长,提高侧根在高磷区域的密度,说明植物根系在下层低磷区感受到磷胁迫信号后,可促进上层高磷区侧根的形成和发育。     

Morphology and development of floral shoots and organs in certain Zannichelliaeeae

Development of reproductive shoots and associated organs in Vleisia aschersoniana, Althenia filiformis, Lepilaena bilocularis and L. cylindrocarpa (Zannichelliaeeae, sensu Dumortier) has been examined using an epi-illumination technique to provide photographic documentation. Floral shoots share a similar basic developmental pattern. The vegetative shoot is terminated by a unisexual flower, but growth is continued from the axils of leaves immediately below so that fairly regular sympodia develop. Vleisia is most variable in the expression of this pattern. The flowers are simple, consisting of a single stamen or three carpels (one in Vleisia) and show marked similarity in development. Short scale-like appendages, reminiscent of a perianth, develop at the base of the stamen in Althenia and Lepilaena. An outgrowth at the tip of the connective in Lepilaena bilocularis and two at its middle part in Vleisia are initiated at late stages of stamen development. Carpels are subtended by membranous tepal-like appendages that are initiated at the same time as the carpel primordia. Each carpel primordium becomes peltate and develops a bitegmic ovule on the adaxial portion of the carpel wall which in turn overgrows the ovule and ultimately forms a long thin style with either a funnel-shaped (Vleisia, L. cylindrocarpa) , peltate (L. bilocularis) or feathery (Althenia) stigma. Relationships with other Alismatales are discussed.     

Root Morphology and Anchorage of Six Native Tree Species from a Tropical Montane Forest and an Elfin Forest in Ecuador

Root architecture of tree species was investigated at two different altitudes in tropical forests in Ecuador. Increasing altitude was accompanied by higher wind speeds and more shallow soils, while slope angles of both sites were comparable (20–50°). Three tree species typical for the montane forest at 1900 m (Graffenrieda emarginata (Ruiz & Pav.) Triana (Melastomataceae), Clethra revoluta (Ruiz & Pav.) Spreng. (Clethraceae), Vismia tomentosa Ruiz & Pav. (Clusiaceae)) and for the elfin forest at 3000 m (Weinmannia loxensis Harling (Cunoniaceae), Clusia spec. (Clusiacaea) Styrax foveolaria Perkins (Styraceae)) were examined. At 1900 m, 92% of the trees grew upright, in comparison to 52% at 3000 m. At 3000 m, 48% of the trees were inclined, lying or even partly uprooted. At this altitude, all trees with tap roots or with shoots connected by coarse rhizomes, 83% of the trees with stilt roots, and 50% of the trees in which stems or roots were supported by other trees grew upright, suggesting that these characteristics were relevant for tree stability. Root system morphology differed markedly between altitudes. In contrast to 1900 m, where 20% of structural roots originated in the deeper mineral soil, root origin at 3000 m was restricted to the forest floor. The mean ratio of root cross sectional area to tree height decreased significantly from 6.1 × 10⁻³ m² m⁻¹ at 1900 m to 3.2 × 10⁻³ m² m⁻¹ at 3000 m. The extent of root asymmetry increased significantly from 0.29 at 1900 m to 0.62 at 3000 m. This was accompanied by a significantly lower number of dominant roots at 3000 m (2.3 compared to 3.8 at 1900 m). In conclusion, native tree species growing in tropical montane and elfin forests show a variety of root traits that improve tree stability. Root system asymmetry is less important for tree stability where anchorage is provided by a deep and solid root–soil plate. When deep rooting is impeded, root traits improving the horizontal extension of the root–soil plate are more pronounced or occur more frequently. Furthermore, mutual mechanical support of roots and stems of neighboring trees seems to be an appropriate mechanism to provide anchorage in soils with low bulk density and in environments with high wind speeds.     

Morphology of the female reproductive organs of the African lion (Panthera leo)

The topography and splanchnology of the reproductive organs of the African lioness were studied and described in situ and after removal. The kidneys were located far caudally in relation to the thirteenth ribs. The suspensory ligament was very well developed, originated in a fan‐like manner from the dorsolateral abdominal wall lateral to the kidney and extended up to a few centimetres cranial to the kidney. The proper ligament of the ovary as well as the round ligament was well developed. The round ligament inserted on the medial femoral fascia. The left ovary was bigger than the right. The ovarian bursa had a short mesosalpinx that did not cover any part of the ovary and the fimbriae extended along the entire length. The urethral tuberculum as well as the urethral crest were well developed. The left uterine horn was longer than the right. The uterine tube was found to open directly into the tip of the uterine horn and not onto a papilla. The reproductive organs of the lioness resembled those of the domestic cat and dog but with some major differences.     

Functional morphology and paleobiology of the pliocene rodent Actenomys (Caviomorpha: Octodontidae): the evolution to a subterranean mode of life

The Pliocene caviomorph rodent Actenomys has long been recognized as an early fossorial representative of the subfamily Ctenomyinae (Octodontidae), which includes one living genus, Ctenomys (tuco-tucos), and several species widely distributed in South America. To assess the de gree of specialization for digging in Actenomys , we performed morphological comparisons with other octodontid genera (Octodon, Spalacopus , and Ctenomys) of known mode of life and behaviour. As a whole, our results indicate that, in terms of morphological specializations for digging, Actenomys occupies an intermediate position between Octodon , a generalized semi-fossorial rodent which forages above ground, and Ctenomys-Spalacopus , two highly specialized subterranean forms. The position of the deltoid process (humerus) and the length of the olecranon process (ulna)–two traits which affect the out-forces exerted by several forelimb muscles–were in Actenomys intermediate between non-subterranean and subterranean taxa. The skull, particularly the rostrum, appears to be strong, and sagittal and nuchal crests are well marked. The zygomatic arches arc as flared as those of the generalized Octodon. Notably, the upper and lower incisors of Actenomys were extremely procumbent, as in many highly-specialized chisel-tooth digging species. Based upon the stratigraphic and sedimentological analysis of the palaeosoils containing its fossil remains, we suggest that Actenomys lived in an environment of moderate to hig primary productivity. The texture of the palaeosoils indicate that theywere hard and highly cohesive. This situation, which contrasts with that observed in living Ctenomyinae, has relevant implications for burrowing cost. The integration of morphological and palaeoenvironmental data allowed testing of hypotheses about the palaeobiological attributes of this ancestral ctenomyine.     

Morphology of male sex organs and insemination in the grasshopper Taeniopoda eques (Burmeister)

The functional morphology of the male genitalia and the insemination process of Taeniopoda eques were examined using scanning electron microscopy and dissections of mating pairs. Male accessory glands consist of 17 separate tubules belonging to eight categories. Males attach to females via a genital locking mechanism, with special motions of the four aedeagal valves aiding in insertion of the aedeagus. The male passes a series of spermatophores. Each is emptied of its spermatodesm contents, then extracted from the male and female genital tracts through motions of the aedeagal valves, while the pair remain in copulo. This allows the male to keep a strong hold on the female, presumably preventing usurpation by other males, while filling the spermatheca with sperm.     

Morphology and development of the haptors among the Monocotylidae (Monogenea)

Monocotylid monogeneans inhabit a wide diversity of sites on their chondrichthyan hosts including the skin, gills, nasal fossae, urogenital system and coelom. The large variation in the morphology of the haptor appears to reflect this diversity in attachment sites. We demonstrate that the complexity of the haptor can be related to the habitat of the parasite. Generally, those parasites which live in habitats subject to strong water currents such as the gills and dorsal skin surface have more complex haptors than those in environments exposed to weaker or no water currents including the nasal fossae, urogenital system and body cavity. However, there can be considerable variation in haptoral components, even among congeners, living on the ‘gills’ of their hosts. The microhabitat was determined for Monocotyle helicophallus and M. spiremae, both from the gills of the pink whipray, Himantura fai, and M. corali from the gills of the cowtail ray, Pastinachus sephen. We demonstrate that differences in the morphology of the hamuli and the number and morphology of septal sclerites and marginal papillae among these species of Monocotyle can be related directly to their microhabitat. It also appears that different haptoral structures are important for attachment to the host at different stages in the development of the parasite, based on studies on the development and distribution of Neoheterocotyle rhinobatidis from the gills of the common shovelnose ray Rhinobatos typus. This revised version was published online in July 2006 with corrections to the Cover Date.     

Modelling and simulation of the architecture and development of the oil-palm (Elaeis guineensis Jacq.) root system

A stochastic model of oil-palm (Elaeis guineensis Jacq.) root system architecture and development has been developed. This model enabled us to create 3-D numerical models of complete root systems by simulation. The application of a postprocessor software, called RACINES, to these 3-D numerical models, provided an estimation of some parameters of plant root systems. The objective of this paper is to present oil-palm root characteristics as possible outputs of the application of this RACINES software. The outputs described in this article cover (i) spatial distribution of roots under plantation conditions, (ii) the estimation and distribution of total root biomass, per root type or per soil horizon and (iii) the location and quantification of absorbent surfaces. The computing techniques used were based on voxellization of space and creation of 3-D virtual sceneries exactly reproducing observed planting designs. By comparing the results of observations and simulations for spatial distribution (by trench wall density maps) and root biomasses (by real and virtual sampling) we were able to carry out additional numerical validations of the model.     

Bioenergetics of reproduction and pup development in a subterranean rodent (Ctenomys talarum)

The objective of this study was to evaluate the maternal costs of reproduction and pup development in the subterranean rodent Ctenomys talarum (Thomas 1898). Statistical differences were detected in whole-animal metabolic rates between nonreproductive and pregnant or lactating females. Whole-animal metabolic rates during pregnancy and lactation were 128% and 151% of the resting metabolic rate (RMR) observed in nonreproductive females. The total additional energy cost of reproduction (above the nonreproductive level) was similar for both the gestation and lactation periods. Mass-specific RMR revealed an upregulation of cell or tissue metabolism during lactation but not during gestation. The mass-specific metabolic rate of pups was 237% of the adults' metabolic rates. No differences were observed in body temperature among nonreproductive, pregnant, or lactating females. No differences were detected in body mass at birth among pups from litters with different numbers of nestlings. Pups increased their body temperature, reaching adult temperature at 30 d of age, when they were near weaning. Milk constituted the exclusive food for pups until they started eating solid food at 10 d old. Suckling time decreased with age of pups, and at the same time, mother chases directed toward their pups increased. These reproductive characteristics may contribute to successful existence in a subterranean habitat.     

Morphology and ultrastructure of possible integumentary sense organs in the estuarine crocodile (Crocodylus porosus)

The skins of crocodylids and gavialids can be distinguished from those of alligatorids by the presence of darkly pigmented pits, known as integumentary sense organs (ISOs), on the postcranial scales. The structure of ISOs, in Crocodylus porosus, was studied using light microscopy and scanning and transmission electron microscopy. The stratum corneum of the epidermis in the area of the ISO is thinner, while the stratum germinativum is thicker, relative to other regions of the integument. Beneath the epidermal layer the ISO region has a paucity of collagen fibers relative to the rest of the dermis. Widely dispersed fibrocytes, nerve terminals, and chromatophores occur throughout the ISO region of the dermis, but these elements are concentrated in the area immediately beneath the stratum germinativum in the ISO region. The morphology of the ISOs suggests that they are sensory organs. It has traditionally been assumed that sensory organs on the amniote integument have a mechanosensory function. However, alternate functional interpretations of this structure are possible, and a resolution awaits further work. © 1996 Wiley-Liss, Inc.     

Morphology and behaviour: functional links in development and evolution

Development and evolution of animal behaviour and morphology are frequently addressed independently, as reflected in the dichotomy of disciplines dedicated to their study distinguishing object of study (morphology versus behaviour) and perspective (ultimate versus proximate). Although traits are known to develop and evolve semi-independently, they are matched together in development and evolution to produce a unique functional phenotype. Here I highlight similarities shared by both traits, such as the decisive role played by the environment for their ontogeny. Considering the widespread developmental and functional entanglement between both traits, many cases of adaptive evolution are better understood when proximate and ultimate explanations are integrated. A field integrating these perspectives is evolutionary developmental biology (evo-devo), which studies the developmental basis of phenotypic diversity. Ultimate aspects in evo-devo studies--which have mostly focused on morphological traits--could become more apparent when behaviour, 'the integrator of form and function', is integrated into the same framework of analysis. Integrating a trait such as behaviour at a different level in the biological hierarchy will help to better understand not only how behavioural diversity is produced, but also how levels are connected to produce functional phenotypes and how these evolve. A possible framework to accommodate and compare form and function at different levels of the biological hierarchy is outlined. At the end, some methodological issues are discussed.     

地下啮齿动物视觉系统的形态结构与机能进化

感觉系统的适应进化机制一直是动物行为学研究的焦点。生活在特殊环境中的动物,其感觉系统在进化过程中表现出的显著差异更是引人注目。由于适应地下黑暗生活环境,地下啮齿动物感觉系统在各个组织水平都表现出进化和退化镶嵌的形态特征,其视觉系统表现得最为突出：视觉器官退化,有关图象分析结构、由视觉诱导产生行为反应的脑区及视觉投射严重退化,有关感受光周期的“非成像” 视觉通路结构高度发达。本文综述了地下啮齿动物视觉系统的结构、功能、进化与发育等方面的研究进展,旨在阐明地下啮齿动物视觉系统的特点,有助于开展地下啮齿动物视觉系统适应进化机制的研究。     

Morphology of the alimentary and reproductive organs of Luciola discicollis Cast. (Coleoptera: Lampyridae)

The morphology of the alimentary and reproductive organs of L. discicollis (Coleoptera: Lampyridae) was studied in detail. The alimentary canal possesses a pouch-like proventriculus. It is suggested that this structure was once functional in ancestral Lampyridae. The details of the reproductive organs are given and it appears that they might be of value in determining the inter-relationships of the families included in the superfamily Cantharoidea. Male and female specimens of L. discicollis have been found to exhibit sexual dimorphism particularly marked in respect of the gut and the size of the eyes.