Modeling of spatial variations of growth within apical domes by means of the growth tensor. Pt. 1. Growth specified on dome axis

By using the growth tensor and a natural curvilinear coordinate system for description of the distribution of growth in plant organs, three geometrie types of shoot apical domes (parabolic, clliptical and hyperbolic) were modcled. It was assumed that apical dome geometry remains unchanged during growth and that the natural coordinate systems are paraboloidal and prolate spheroidal. Two variants of the displacement yelocity fields V were considered. One yariant is specified by a constant relative elemental ratę of growth along the axis of the dome. The second is specified by a ratę inereasing proportionally with distance from the geometrie focus of the coordinate systems (and the apical dome). The growth tensor was used to calculate spatial yariations of growth rates for each yariant of each dome type. There is in both yariants a elear tendency toward lower growth rates in the distal region of the dome. A basie condition for the existence of a tunica is met

Trajectories of principal directions of growth, natural coordinate system in growing plant organ

In symplasticly growing organs the principal directions of growth, which are indicated by the eigenvectors of the symmetric part of the growth tensor, can be associated with each positional point and joined up to form a network of orthogonal trajectories, uolcss the growth is isotropic. The trajectories represent a natura( coordinate system suitable for description of growing orgaos. These trajectories often can be recognized in patterns of nonrandom aligoments in the cell wali network: these alignmeots are norma\ to anticlinal and periclinal walls. Coordioate systems that fit the trajectories in different types of growiog organ are listed

Ecosystem Services – Theories and Applications: Opportunities for Humanity to Regain Paradise

Ecosystem services, the benefits humans derive from nature, represents a radical departure in our perception of linked environmental and social problems and the actions we need to undertake to address those urgent challenges. Due to its increasingly widespread policy prominence, understanding and appraising its conceptual and practical benefits whilst at the same time acknowledging its potential pitfalls represents an important endeavour. Comprising seven parts and sixteen chapters, the first five parts of the thesis outline the main environmental and social challenges we face, presenting the core foundations, contemporary debates and developments in ecosystem services scholarship, whilst also underlining its increasing coalescence with sustainability discourse. In Part 6 we focus on a key application of ecosystem services with respect to its translation into incentive-based environmental management schemes, namely: payment for ecosystem service programmes and agri-environment schemes. We present a systematic global analysis of payment for ecosystem services programmes, highlighting the successes and challenges they face, whilst also providing an approach to improve their design and evaluation as a route to maximise their effectiveness. Turning our attention to a globally significant ecosystem, the thesis assesses the prospects for jointly developing seagrass Blue Carbon initiatives and payment for ecosystem service schemes, arguing that complementing these activities would produce significant climate, conservation and livelihood benefits. Switching contexts, from focusing on incentive schemes primarily in operation in developing countries to those designed to balance productivity and conservation matters in the agricultural sector of developed countries – the thesis explores the stakeholder and institutional factors affecting agri-environment scheme operation and implementation through the eyes of key operatives. Finally, in Part 7, I argue that a landscape framing and approach to ecosystem services provides an effective route to improve environmental management decision-making and policy as well as comprehensively addressing the linkages between ecosystem services and human-wellbeing

Perception of gravity expressed by production of cambial callus in ash (Fraxinus excelsior l.) internodes

In ash internodes isolated from vertical stems during winter dormancy, cambial activity was stimulated by applying an aqueous solution of auxin to the apical end and water to the basal end. The internodes maintained nearly horizontally produced cambial callus at the apical cut surface with more callus on the upper half although both halves were in contact with the same concentration of auxin. A differential response to auxin of the cambium in the upper and lower halves of the horizontally oriented internodes is postulated

Occurrence of circular vessels above axillary buds in stems of woody plants

The circular vcsscls gencrally occur in intact wood stems just above the axillary buds. In this region the cell arrangement with vortices occurs. We interprete the circular vessels as the result or circular polarity in the cambial zone or the region above the axillary bud. The stability or circular polarity in this region is based on the vorticity or the cambium cells arrangement

Designing public agencies for 21st century water–energy–food nexus complexity : the case of Natural Resources Wales

Public environmental organisations face a Herculean task: to be responsive to public and executive expectations for decentralisation, integration, increasing accountabilities and efficiency savings plus, contemporaneously, managing increasingly complex nature–society systems as exemplified by the water–energy–food nexus. The public-agency innovation literatures and contingency theory offer partial explanations for this challenge. However, this article, which sits at the intersection of public administration and organisational theory, proposes a new analytical framework for framing public-agency responses to nexus complexity. It first outlines the framework and then tests it on the case of Natural Resources Wales, the Welsh national natural environment agency. This case identifies six distinct innovations that have adopted to meet complex nexus pressures. This leads us to characterise the case as an example of a multi-scalar, hybrid, adhocratic organisation designed to meet nexus challenges. These findings have wider impact for the international community of public agencies with socio-environmental remits facing similar nexus pressures and challenges in the 21st century

Environmental policy design and implementation : toward a sustainable society

We acknowledge funding by The Centre for the Evaluation of Complexity Across the Nexus, a UK Economic and Social Research Council large centre (project number: ES/N012550/1) and the UK Research Innovation’s Global Challenges Research Fund (UKRI GCRF) Living Deltas Hub. Plus, the UK Research and Innovation’s Global Challenges Research Fund (UKRI GCRF) through the Development Corridors Partnership project (project number: ES/P011500/1).Publisher PDFPeer reviewe

An oscillatory component of propagated fluctuation electric potential in lupine shoot

Application of a drop of auxin solution to a cut surface on the petiole in lupine shoot elicits a travelling pulse of electric potentia) decrease. This pulse was simulta­neously recorded by means of a DC amplifier and band-pass amplifier 0.1-100 Hz, both connccted to the same exploring AgCI electrode driven into the stem. The DC record shows a pulse 20-80 mV in height of about 30 s duration at its height with smooth slopes. The band-pass amplifier shows one to a few pairs of spikes (negative and positive) whose amplitude is at least of an order lower than that of the DC pulse. Thcse spikcs are interpretcd as the action potentia) of certain excitable cclls rccorded in a --volume conductor"·. The pulse is interpreted as a wave of cooperative depolarization of excitable and a mass of inexcitable cells

Localized spontaneous fluctuations of electric potential in shoots of differentplants

Sharp short-lasting voltage nuctuation is one of the components of plant electric activity. Common appearance of such fast signals (FS) in the stems of severa) species has been found. Obscrved spatial distribution of its amplitude excludes the possibilit} of an artefact. deriving from the electrode surface --- plant tissue interaction. The hypothesis that FS are due to action potentia) of a single cell or a small group of cells observed in a volume conductor is considered

Modeling of spatial variations of growth within apical domes by means of the growth tensor. Pt. 2. Growth specified on dome axis

Variations of the elemental relative rate of growth are modeled for parabolic, elliptic and hyperbolic domes of shoot apices by using the growth tensor in a suitable curvilinear coordinate system when the mode of area growth on the dome surface is known. Variations of growth rates within the domes arc obtained in forms of computer-made maps for the following variants of growth on the dome surface: (I) constant meridional growth rate, (2) isotropic area growth, (3) anisotropy of area growth which becomes more intensive with increasing distance from the vertex. In variants I and 2 a maximum of volumetric growth rate appears in the center of the dome. Such a distribution of growth seems to be unrealistic, However, the corresponding growth tensors are interesting because they can be used in combination with other growth tensors to get the expected minimum volumetric growth rate in the dome center