Linnea Hesse

University of Freiburg | Albert-Ludwigs-Universität Freiburg · Botanical Gardens

The Opuntioideae include iconic cacti whose lateral branch–branch junctions are intriguing objects from a mechanical viewpoint. We have compared Opuntia ficus-indica, which has stable branch connections, with Cylindropuntia bigelovii, whose side branches abscise under slight mechanical stress. To determine the underlying structures and mechanical c...

Nodes are interfaces between stems and leaves. Vascular bundles originate here and elongate into leaves and internodes. In Marantaceae, internodal bundles are highly diverse, including inverted bundles in the climbing genus Haumania. The objective of this paper is to characterize bundle forms, their position across the stem and their connection to...

Within the Aizoaceae, the genus Delosperma exhibits a vast diversification colonizing various ecological niches in South-Africa and showing evolutionary adaptations to dry habitats that might include rapid self-sealing. Leaves of Delosperma react to external damage by the bending or contraction of the entire leaf until wound edges are brought into...

The fruits of Chinese witch-hazel (Hamamelis mollis, Hamamelidaceae) act as 'drying squeeze catapults', shooting their seeds several metres away. During desiccation, the exocarp shrinks and splits open, and subsequent endocarp deformation is a complex three-dimensional shape change, including formation of dehiscence lines, opening of the apical par...

Bridges and roofs are often supported by branched steel columns. Their production is usually expensive and consumes a great deal of energy. In nature, plants manage to form similarly strong and frequently even more complex branch systems through natural growth processes. They can effortlessly withstand mechanical loads, such as their own weight, wi...

Branched loadbearing structures have a long tradition in architecture. After centuries of application, the principle of this construction method is still valid today and results in good structural systems. It is obvious why this is so: owing to the form-active design, slender branched columns are effective supports for roofs and floor decks.

Brücken und Dächer werden oft durch verzweigte Stahlstützen getragen. Diese sind in ihrer Herstellung meist teuer und energieaufwendig. In der Natur gelingt es Pflanzen, ähnlich stabile und häufig noch komplexere Verzweigungen durch natürliche Wachstumsprozesse zu bilden. Sie können mechanischen Belastungen mühelos standhalten, wie z. B. ihrem Eige...

Brücken und Dächer werden oft durch verzweigte Stahlstützen getragen. Diese sind in ihrer Herstellung meist teuer und energieaufwendig. In der Natur gelingt es Pflanzen, ähnlich stabile und häufig noch komplexere Verzweigungen durch natürliche Wachstumsprozesse zu bilden. Sie können mechanischen Belastungen mühelos standhalten, wie z. B. ihrem Eige...

In many biomimetic approaches, a deep understanding of the form-structure-function relationships in living and functionally intact organisms, which act as biological role models, is essential. This knowledge is a prerequisite for the identification of parameters that are relevant for the desired technical transfer of working principles. Hence, non-...

Three- and four-dimensional imaging techniques are a prerequisite for spatially resolving the form-structure-function relationships in plants. However, choosing the right imaging method is a difficult and time-consuming process as the imaging principles, advantages and limitations, as well as the appropriate fields of application first need to be c...

A numerical computer model was developed in order to describe the complex self-sealing mechanism of injured Delosperma cooperi leaves. For this purpose, the leaf anatomy was simplified to a model consisting of five concentric tissue layers. Specific parameters (modulus of elasticity, permeability, porosity, etc.) were assigned to each tissue type f...

The development of the branch-stem-attachment of Dracaena marginata was analyzed to clarify how a load-adapted arrangement of mechanically relevant tissues, i.e. the vascular bundles with fiber caps, is established during ontogeny. For this purpose, 3D images of four intact and developing buds of D. marginata were repetitively acquired in vivo with...

This chapter describes the basic principles of using magnetic resonance imaging (MRI) sequences for the specific purpose of nuclear magnetic resonance (NMR) microscopy. A major difference between NMR microscopy and small animal MR or human MR lies in the fact that in NMR microscopy, it is not sufficient to just make an image. The versatility of MR...

The present thesis introduces a new methodological approach based on magnetic resonance imaging (MRI) which allows for analyzing the development and load-adapted strategy of plant structures. Thus, the application of MRI could be extended to the fields of functional morphology, biomechanics and biomimetics of plants. MRI allows for repetitive non-...

Plant movements can inspire deployable systems for architectural purposes which can be regarded as ideal solutions combining resilient bio-inspired functionality with elegant natural motion. Here, we first give a concise overview of various compliant mechanisms existing in technics and in plants. Then we describe two case studies from our current j...

Magnetic resonance imaging (MRI) was used to gain in vivo insight into load-induced displacements of inner plant tissues making a non-invasive and non-destructive stress and strain analysis possible. The central aim of this study was the identification of a possible load-adapted orientation of the vascular bundles and their fibre caps as the mechan...

The aim of this study is the biomimetic optimisation of branched fibre-reinforced composites based on the detailed analysis of biological concept generators. The methods include analyses of the functional morphology and biomechanics of arborescent monocotyledons and columnar cacti as well as measurements and modelling of mechanical properties of bi...

Plants with a climbing growth habit possess unique biomechanical properties arising from adaptations to changing loading conditions connected with close attachment to mechanical supports. In monocot climbers, mechanical adaptation is restricted by the absence of a bifacial vascular cambium. Flagellaria indica was used to investigate the mechanical...

Background and AimsThe order Piperales has the highest diversity of growth forms among the earliest angiosperm lineages, including trees, shrubs, climbers and herbs. However, within the perianth-bearing Piperales (Asarum, Saruma, Lactoris, Hydnora, Prosopanche, Thottea and Aristolochia), climbing species only occur in the most species-rich genus Ar...