Wood Anatomy of Drimys S.S. (Winteraceae)

Qualitative and quantitative data are reported for seven specimens representing six varieties of the four species of Drimys generally recognized. Tracheid length and diameter are correlated both with plant size and with severity of climate: wide, long tracheids, not fluctuating in diameter seasonally, occur in Drimys of moderate elevations in subtropical latitude; narrower, shorter tracheids, becoming radially narrower briefly in latewood, occur in Drimys from higher altitudes and latitudes. Vesturing (warty layer) on the inside surface of tracheids occurs in Drimys from latitudes and altitudes where appreciable freezing is to be expected, but vesturing is absent at lower elevations and latitudes. Vesturing may bond water to tracheid walls better so that water columns do not break under high tensions produced by such conditions as transpiration when soil remains frozen. Scalariform pitting on end walls of Drimys tracheids occurs during the first year (metaxylem), but is replaced by alternate circular pits later; injury to the cambium, even of a mild kind, results in reversion to sca1ariform end wall pitting. Tracheid wall thickness is not correlated with tracheid diameter. Tracheid-ray pits are 75% the diameter of tracheid-tracheid pits. Axial parenchyma is sparse and diffuse (occasionally cells in tangential or radial pairs). Rays are Heterogeneous Type I; ray cells commonly have bordered pits on tangential walls. Silica bodies are reported (first report for Winteraceae) in rays of three collections of Drimys

Longitudinal methods for analysis of early child health in Pakistan

Statistical methods to analyse some aspects on early child health in Lahore, Pakistan are discussed. The aim of this thesis is to choose, examine and use statistical methods suitable to analyse different aspects of early child health in a developing country when the child is measured repeatedly over time (longitudinal data). This kind of data are very informative but require care in the choice of statistical method, since seemingly similar analyses can give quite different answers. This licentiate thesis consists of two parts, which will be referred to in the text by their Roman numerals: I: Anders Carlquist, Valdemar Erling, Rifat Ashraf, Marianne Frisen, Fehmida Jalil, Lars A Hanson, Shakila Zaman. The impact of season and climate on growth during early childhood in different socio-economic groups in Lahore, Pakistan. Research Report, Department of Statistics, GOteborg University 1999:10. II: Anders Carlquist, Valdemar Erling and Marianne Frisen. Longitudinal Models for Analysis of the Influence of Breastfeeding on Early Child Health in Pakistan Research Report, Department of Statistics, Goteborg University 1999:11. In report I, an explorative cross-sectional analysis is first made to examine the main features of some relations between variables. Then, the method of derived variables is used to investigate the longitudinal patterns. The method of derived variables (also called the method of summary statistics or two-stage method) is a simple and often very effective method. The first step is to summarise the repeated values into a summary statistic, which then, in the second step is analysed. This method has been advocated for it's many attractive features. The results are readily interpretable. No assumptions are needed about the covariance structure among the repeated measures (but it is useful to take it into account when choosing the summary statistic). These methods are used to study the impact of temperature on health, measured as growth. In Lahore, Pakistan temperature was shown to be a factor that influences child health. It is demonstrated that the impact is quite different in different ages and areas of living. In report II, we aim to elucidate the causal effects of breastfeeding on early child health, measured as occurrence or not of diarrhoeal episodes. Here it is not possible to use the method of derived variables. We use generalised linear mixed models to construct a model for the binomial response variable and use both fixed and random explaining effects. In order to elucidate the causal effects of breastfeeding on early child health we use the two-step approach recently advocated in the statistical literature but modify the procedure to be practicable for the present longitudinal study. The selection effects of breastfeeding are examined and variables with major effect on the breastfeeding pattern are included in the final model. For some, but not all, areas of living the analysis then motivates the conclusion that breastfeeding helps prevent the occurrence of diarrhoe

Wood Anatomy of Crossosomatales: Patterns of Wood Evolution with Relation to Phylogeny and Ecology

The seven families hypothesized by Sosa and Chase to comprise Crossosomatales possess relatively long vessel elements with scalariform perforation plates and scalariform to opposite vessel-ray pitting; tracheids; diffuse axial parenchyma; and heterogeneous rays. These and other primitive character states do not indicate relationships, but they do not offer any evidence against the idea that Crossosomatales are a natural order. Departures from the primitive character states are related to ecological adaptations. Crossosomataceae have simple perforation plates (scalariform briefly at the beginning of the secondary xylem), a feature correlated with the seasonal aridity of habitats occupied by the family, the sole family of the order to exhibit such an ecological shift. Presence of tracheids (which confer embolism resistance to a wood) in ancestors of Crossosomataceae probably pre-adapted the family for entry into highly seasonal habitats. Minimal vessel grouping in all other genera shows that tracheid presence deters vessel grouping; tracheid presence also deters shortening of vessel elements. Autapomorphies are shown by Aphloiaceae (tracheid dimorphism, rays of two distinct widths); Crossosomataceae (perforation plates predominantly simple, lateral wall pitting of vessels alternate); Geissolomataceae (wide rays); Ixerbaceae (fiber-tracheid tendency); Staphyleaceae (adjacence of axial parenchyma to vessels); Stachyuraceae (simplification of perforation plates); and Strasburgeriaceae (large cell size). Although tracheid presence seems plesiomorphic in Crossosomatales, a degree of lability in density and size of bordered pits on imperforate tracheary elements probably occurs within this order and in other dicotyledon groups

Wood Anatomy of Gnetales in a Functional, Ecological, and Evolutionary Context

New scanning electron microscope (SEM) and light microscope data and illustrations are presented in order to compare hydraulic adaptations of non-gnetalean conifers and angiosperms to relevant wood features of Gnetales. Gnetales have essentially all of the adaptations of both groups, yet have not competed well, despite predating angiosperms in origin and radiation. Angiosperms may be advantaged more by life cycle abbreviation and by heterochronic possibilities than by wood features. Wood features of Gnetales that relate to conduction (torus-margo differentiation of tracheid pit membranes, distribution of tori within the wood, perforation plate simplification, growth rings, vesturing, helical thickenings, and axial parenchyma) are reviewed in the light of recent work that demonstrates the physiological significance of these features in angiosperms. The various xylary adaptations of Ephedra, Gnetum, and Welwitschia are analyzed in terms of conductive efficiency versus conductive safety, and in turn, compared to the habitats of the three genera, respectively: Ephedra and Welwitschia survive in rather extreme habitats, whereas Gnetum competes in mesic forest by what may be minor shifts among basically similar niches. Gnetales have essentially all of the wood anatomical advantages of angiosperms, except for ability to shift degrees of wood anatomical juvenilism or adulthood—an important angiosperm advantage. The relatively lengthy life cycle of Gnetales, requiring female gametophyte formation prior to embryo formation (vs. simultaneous endosperm and embryo development in angiosperms) and the related requirement for at least several years\u27 growth prior to seed formation are probably the prime reasons for lack of gnetalean success. Wood features should be interpreted as adapted to the present-day ecology of a woody species, and ideas that evolutionary flexibility to shift into more seasonal conditions is hindered by rigid wood formulas (which actually can change rather rapidly) should be questioned. Wood evolution of Gnetales, like that of angiosperms, can be regarded as a series of shifts in the trade-offs between conductive efficiency and conductive safety

Non-random Vessel Distribution in Woods: Patterns, Modes, Diversity, Correlations

Vessel grouping is a form of non-random distribution that becomes functionally valuable when the background consists of non-conductive imperforate tracheary elements (fiber-tracheids and libriform fibers); ungrouped vessels, randomly placed, often occur in an all-tracheid background. Types of vessel grouping are described and illustrated: diagonal, tangential, radial, median radial bands, and growth rings. Other non-random distributions considered include degrees and kinds of cable construction, patchy vessel distributions, vessel displacement related to succulence, and patterns involving successive cambia. Non-random vessel distributions inevitably involve non-random placement of imperforate tracheary elements, so that a parallel set of mechanical adaptations is often simultaneously achieved. Correlations between various types of non-random vessel patterns and possible physiological factors are hypothesized. Most correlations involve enhanced conductive safety, but vessel distribution related to water and photosynthate storage, resistance to torsion, and increased longevity of xylem are cited. Non-randomness of vessels is a source of diversity in wood structure that can be achieved readily (as growth rings show) and polyphyletically. These modifications offer numerous ways in which wood histology can be repatterned for probable adaptations in conductive physiology, mechanical strength, and storage capability, perhaps by means of regulatory genes. Grouping of vessels into vascular bundles in primary xylem of stems and leaves in dicots is a form of non-randomness, and the significance of vascular bundles (as opposed to steles) as adaptive forms of organization is considered briefly. Monocots differ from dicots in rarely having division of labor in tracheary elements within an organ, but monocots exhibit tradeoffs in which conductive efficiency (vessel presence in an organ) and conductive safety (tracheids but no vessels in an organ) can be achieved within a single plant

Wood and Bark Anatomy of Myricaceae: Relationships, Generic Definitions, and Ecological Interpretations

Wood anatomy of the single species of Canacomyrica (hitherto not studied) shows that it belongs in Myricaceae, although it differs from other genera in several respects (axial parenchyma grouped in bands or columns as well as diffuse; Heterogeneous Type I rays; more numerous bars per perforation plate). The latter two features are primitive for the family. The four genera (Canacomyrica. Comptonia, Morella, and Myrica s.s.) differ from each other not only by qualitative features but by quantitative features (feature means in genera mostly non- overl apping). Wood of Comptonia and Myri ca s.s. lacks chambered crystals in axial parenchyma and ray crystals. Wood of Myrica s.s. has tracheids in latewood but fiber-tracheids in earl ywood. Diagnostic generic summaries are presented. Features of Myricaceae such as scalarifom perforation plates, presence of (true) tracheids , ray types , chambered encapsulated crystals in axial parenchyma, and bark anatomy correspond with character states and expressions in Betulaceae, Casuarinaceae, Corylaceae, Juglandaceae (including Rhoipteleaceae), Ticodendraceae and, to a lesser extent, Fagaceae and Nothofagaceae. This grouping of families can be found as Fagales in recent DNA trees. The predominance of tracheids in basal Fagales such as Myricaceae and Ticodendraceae suggests that origin of vasicentric tracheids which occur in combination with libriform fibers in Fagaceae is the product of tracheid dimorphism. Low imperforate tracheid length to vessel element length ratios (FN ratios) in Myricaceae are a probable indication of wood primitiveness. Quantitative vessel features of Myricaceae, as combined in Mesomorphy Ratio values, characterize wood of Myricaceae as a whole, but at the species level such values correspond to respective habitats; notably high vessel density in Comptonia may represent greater conductive safety appropriate to relatively dry habitats

Wood Anatomy of Cneoraceae: Ecology, Relationships, and Generic Definition

Wood anatomy of the three species of Cneorurm is described qualitatively and quantitatively. The species differ in features related to ecology and form a clear series in this regard. The wood features of the family can all be matched by some Rutaceae and Simarubaceae, and the characteristics of Cneoraceae are listed in this connection. Nearly as many features are shared by Cneoraceae with Anacardiaceae and Sapindaceae; certain distinctive features may be found in somewhat more distant families, such as Oxalidaceae. Resemblances between Cneoraceae and Euphorbiaceae are attributed at least in part to the fact that Euphorbiaceae comprise a highly heterogeneous family with respect to wood anatomy. Wood anatomy of the three species of Cneorurm diverges markedly. These differences when tabulated show that the Cuban species C. trimerum is the most distinctive. Cneorum pulverulentum (Canary Islands) and C. tricoccon (northwestern Mediterranean coasts), although distinct in wood anatomy, resemble each other more closely than they resemble C. trimerum. Despite the distinctive tetramerous flowers and hexacolpate pollen of C. pulverulentum, a single genus seems advisable; C. trimerum cannot be readily segregated on the basis of gross morphology

Trematolobelia: Seed Dispersal; Anatomy of Fruit and Seeds

The endemic Hawaiian genus Trematolobelia (Lobeliaceae, or Campanulaceae, subfamily Lobelioideae) was erected on the basis of its distinctive fruit. This fruit has a seed-dispersal mechanism unique in the family. Assertions have been made by some workers that holes in the fruit wall are the work of insects, and are not related to the dispersal mechanism. This contention has been adequately disproved by other investigators, but, in fact, the precise nature of the dispersal mechanism and the anatomical structure responsible for its action have never been adequately described. In addition, the present study reveals the potential taxonomic use of capsular anatomy, a feature of importance because various authors recognize one, two, or three species in the genus. These species are based largely on floral features or foliar characteristics, and not on those of the fruit. Unusually good material of Trematolobelia collected by the writer during the summer of 1958 provides a sufficient basis for presenting the features mentioned above in some detail

Wood and Stem Anatomy of Phytolaccoid and Rivinoid Phytolaccaceae (Caryophyllales): Ecology, Systematics, Nature of Successive Cambia

Quantitative and qualitative wood features are presented and analyzed for seven species of subfamily Rivinoideae and four of subfamily Phytolaccoideae. All species have nonbordered perforations plates, as elsewhere in suborder Phylocaccineae. Libriform fibers characterize both subfamilies, but vasicentric tracheids occur in two rivinoid species. Axial parenchyma is vasicentric scanty (apotracheal bands and patches in one species). Rays are mostly multiseriate, with procumbent cells infrequent in most species. Rivinoids and phytolaccoids differ from each other in ray height and width and in crystal types. The xeromorphic wood of Petiveria and Rivina is related to their short duration (woody herbs) in disturbed soil that dries readily. Woods of other genera are moderately mesomorphic, correlating with seasonally tropic habitats. Genera of Phytolaccaceae studied here have the same ontogenetic features leading to successive cambia as Stegnosperma. Phytolacca dioica has amphivasal pith bundles in which secondary growth occurs. Vessel restriction patterns are newly reported for the family