The formation of integuments, megasporogenesis and megagametogenesis in Dendrobium catenatum, with special discussions on embryo sac types and section techniques

The formation of integuments, megasporogenesis and megagametogenesis in Dendrobium catenatum, an economically important orchid, are observed. After pollination, mitotic cell divisions of the placental epidermis result in the formation of a branching system of outgrowths. The tip of each branch consists of an archesporial cell derived from the differentiation of the terminal subepidermal nucellar cell. It differentiates directly into a megasporocyte. The first division of the meiosis of the megasporocyte produces a dyad approximately equal in size, in which the micropylar cell promptly degenerates. The second meiotic division of the remaining dyad cell results in the formation of two megaspores of unequal size. The larger chalazal cell becomes functional and eventually develops into a mature megagametophyte. The development of the megagametophyte conforms to the Monosporic Polygonum type. The final arrangement of the mature embryo sac conforms to a sevencelled/ eight-nucleate structure. The mature ovule is bitegmic, tenuinucellate and has an anatropous orientation. In the present study, we also discuss the differences between three main types of embryo sac development and the improvement of section techniques.

Introduction of Fractal-Based Tree Digitalization and Accurate In-Canopy Radiation Transfer Modelling to the Microclimate Model ENVI-met

While complex urban morphologies including different materials, wall structures, etc., are rather adequately represented in microclimate models, replication of actual plant geometry is—so far—rather crudely handled. However, plant geometry greatly differs within species and locations while strongly determining a plant’s microclimate performance. To improve the plants representation in numerical models, a new method to describe plant skeletons using the so-called Lindenmayer-System has been implemented in the microclimate model ENVI-met. The new model allows describing much more realistic plants including the position and alignment of leaf clusters, a hierarchical description of the branching system and the calculation of the plant’s biomechanics. Additionally, a new canopy radiation transfer module is introduced that allows not only the simulation of diffuse radiation extinction but also secondary sources of diffuse radiation due to scattering of direct radiation within plant canopies. Intercomparisons between model runs with and without the advancements showed large differences for various plant parameters due to the introduction of the Lindenmayer-System and the advanced radiation scheme. The combination of the two developments represents a sophisticated approach to accurately digitize plants, model radiative transfer in crown canopies, and thus achieve more realistic microclimate results.

Morphology and symmetry of the vegetative parts of Smilax auriculata (Smilacaceae)

Smilax auriculata produces a subterranean rhizome system and an aerial vegetative branching system. Three intergrading types of stems (types 1, 2, and 3) compose the aerial branching system; these types are identified primarily according to prickle concentration, but also differ from one another in additional ways. Type-3 stems are determinate and either proleptic or precocious. Between growing seasons a foliage leaf of a type-3 stem may subtend either a solitary vegetative bud (or an expanded vegetative branch) or an inflorescence superposed over a vegetative bud (or expanded vegetative branch). Occasionally, an inflorescence terminates a type-3 stem. Whereas, rhizomes exhibit solely scale leaves, the aerial vegetative branching system manifests scale leaves, transitional leaves, and foliage leaves. On many type-3 stems the foliage leaves become oriented skyward, by bending of their leaf sheaths and petioles. The aerial vegetative branching system manifests bilateral symmetry and mirror-image symmetry. The inflorescence is a pedunculate umbel. The peduncle culminates in a torus which bears a peripheral whorl of bracts, centripetally situated bracteoles, and pedicellate flowers. Type-1 stems exhibit numerous prickles, which vary from unbranched to branched and from solitary to basally connate in rows.

Two new species of Phialiphora (Spermacoceae, Rubiaceae) exemplify drought adaptations in western Madagascar

Background – Phialiphora (Spermacoceae, Rubiaceae) is a herbaceous genus restricted to unconsolidated white sands in open spaces in dry forests in northwestern Madagascar. The genus is characterized by the semi-succulent nature of its leaves and stems, its basal leaf rosette, its head-like inflorescences subtended by large leaf-like involucrate bracts and its isostylous flowers. Hitherto, only two species were described.Methods – Classical methods of herbarium taxonomy are followed.Key results – Two new Phialiphora species, P. glabrata De Block and P. valida De Block, are described, which brings the number of species in the genus to four. The two new species differ from the two previously described species by their glabrous branches, bracts, ovaries, calyces and fruits. They are easily distinguished from each other by the shape and size of the calyx lobes. A detailed description, illustration, distribution map and preliminary conservation assessment is given for the new species, which are assessed as critically endangered. We also present a key for the genus and discuss in detail the typical branching system, the capsules and the dispersal mechanism of Phialiphora. The description of these two new species exemplifies the uniqueness of the dry vegetations on unconsolidated white sands in western Madagascar, which are characterized by a high level of endemicity.

Irreducible and permutative representations of ultragraph Leavitt path algebras

We completely characterize perfect, permutative, irreducible representations of an ultragraph Leavitt path algebra. For this, we extend to ultragraph Leavitt path algebras Chen’s construction of irreducible representations of Leavitt path algebras. We show that these representations can be built from branching system and characterize irreducible representations associated to perfect branching systems. Along the way, we improve the characterization of faithfulness of Chen’s irreducible representations.

Growth dynamics of the branching system in grasses: an architecture-based methodology for quantitative evaluation applied to two genotypes of Paspalum vaginatum

The aerial growth dynamics of the shoots of the widespread turfgrass Paspalum vaginatum was studied. With the aim of identifying quantitative differential features between two genotypes, plants were cultivated outdoors in pots during two consecutive summers. Axes of different branching order were marked for periodical observation to quantify internode production rate, axis production rate, covering rate and reproductive effort. The genotypes differed significantly in the following quantitative features: plagiotropic vs. orthotropic axes proportion, internode production rate, flowering vs. vegetative tiller ratio, vegetative cover and spatial distribution of the canopy. Knowledge of these features may help to understand the great plasticity and adaptability of this species to multiple environmental conditions.

Ludic writing: Challenges in gamifying English creative writing class for technopreneurial purposes

<p>This paper, first of three research parts, attempts to describe the challenges English Letters at IAIN (<em>Institut Agama Islam Negeri/</em>State Islamic Institute) Surakarta faced in implementing gamification for technopreneurial purposes in regard to the transformation of a creative writing class into a ludic writing class, a gamification infused writing class. The challenges revealed are story-game script adaptation, integration portion, and monetization. Specific problems occur on each challenge. Story-game script adaptation exposes three problems namely (1) conditional branching system (2) visualization (3) copyrighted material issues (4) and writing mechanics adaptation. Integration portion challenge displays a problem on the insufficient alloted time for gamifying the creative writing class. Monetization challenge indicates three problems namely (1) the inexistence of monetization team, (2) the inexistence of institutional regulation for monetization management by study programs, (3) responses to gaming trends. Responding to these problems, solutions specifically designed based on the nature of the problems are implemented.</p>

A faixa de dobramentos do Rio Salgado, norte-noroeste da Zona Transversal-Província Borborema (PB-CE)

O sistema de Dobramentos Piancó-Alto Brígida (SPAB) foi definido como um branching system of orogens neoproterozoico na parte centro-ocidental da Zona Transversal-Província Borborema. A discriminação de Faixa de Dobramentos do Rio Salgado (FDRS) está sendo proposta para o ramo mais setentrional deste sistema. Esta faixa (FDRS) está cortada ao norte pelo Lineamento Patos (aqui considerado como um boundary transform continental) e margeada por uma série de basement inliers paleoproterozoicos ao sul (Riacho São Pedro, Icaiçara, S. José do Caiano, Coremas etc.), estando em parte encoberta por sedimentos fanerozoicos do Araripe. Os ramos mais ao sul e sudeste do SPAB estão cortados por dezenas de stocks e batólitos intrusivos (tipo “I”) de um arco magmático continental que se estende da costa paraibana ao sertão do Piauí (ca. 800 km). A FDRS está situada entre este arco magmático e o Lineamento de Patos e é constituída principalmente por sequências siliciclásticas finas de grande ritmicidade, com intercalações locais de sheets de vulcânicas félsicas, intermediárias e básicas. O metamorfismo regional corresponde à fácies xisto verde baixo (sericita-clorita-biotita). Foram realizadas três seções litoestratigráficas e estruturais completas, transversais à FDRS, sendo identificadas preliminarmente cinco distintas unidades paraestratigráficas. Estudos geocronológicos (U-Pb) preliminares indicam uma sedimentação pós-650 Ma. Três fases de deformação foram identificadas e serão discutidas. As características geológicas gerais, a posição tectônica e a natureza do embasamento da FDRS apontam para o desenvolvimento orogênico de uma bacia de antearco no Neocriogeniano.