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Horstmann M, Speck T, Poppinga S. Orchestrated Movement Sequences and Shape-Memory-like Effects in Pine Cones. PLANTS (BASEL, SWITZERLAND) 2024; 13:2078. [PMID: 39124196 PMCID: PMC11313876 DOI: 10.3390/plants13152078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/19/2024] [Accepted: 07/21/2024] [Indexed: 08/12/2024]
Abstract
Hygroscopic seed-scale movement is responsible for the weather-adaptive opening and closing of pine cones and for facilitating seed dispersal under favorable environmental conditions. Although this phenomenon has long been investigated, many involved processes are still not fully understood. To gain a deeper mechanical and structural understanding of the cone and its functional units, namely the individual seed scales, we have investigated their desiccation- and wetting-induced movement processes in a series of analyses and manipulative experiments. We found, for example, that the abaxial scale surface is responsible for the evaporation of water from the closed cone and subsequent cone opening. Furthermore, we tested the capability of dry and deformed scales to restore their original shape and biomechanical properties by wetting. These results shed new light on the orchestration of scale movement in cones and the involved forces and provide information about the functional robustness and resilience of cones, leading to a better understanding of the mechanisms behind hygroscopic pine cone opening, the respective ecological framework, and, possibly, to the development of smart biomimetic actuators.
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Affiliation(s)
- Martin Horstmann
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, 44780 Bochum, Germany
- Plant Biomechanics Group, Botanical Garden, University of Freiburg, 79104 Freiburg im Breisgau, Germany;
| | - Thomas Speck
- Plant Biomechanics Group, Botanical Garden, University of Freiburg, 79104 Freiburg im Breisgau, Germany;
- Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110 Freiburg, Germany
| | - Simon Poppinga
- Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110 Freiburg, Germany
- Botanical Garden, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
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Horstmann M, Buchheit H, Speck T, Poppinga S. The cracking of Scots pine ( Pinus sylvestris) cones. FRONTIERS IN PLANT SCIENCE 2022; 13:982756. [PMID: 36330256 PMCID: PMC9623100 DOI: 10.3389/fpls.2022.982756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
Pine cones show functionally highly resilient, hygroscopically actuated opening and closing movements, which are repeatable and function even in millions of years old, coalified cones. Although the functional morphology and biomechanics behind the individual seed scale motions are well understood, the initial opening of the cone, which is often accompanied by an audible cracking noise, is not. We therefore investigated the initial opening events of mature fresh cones of Scots pine (Pinus sylvestris) and their subsequent motion patterns. Using high-speed and time lapse videography, 3D digital image correlation techniques, force measurements, thermographic and chemical-rheological resin analyses, we are able to draw a holistic picture of the initial opening process involving the rupture of resin seals and very fast seed scale motion in the millisecond regime. The rapid cone opening was not accompanied by immediate seed release in our experiments and, therefore, cannot be assigned to ballistochory. As the involved passive hydraulic-elastic processes in cracking are very fine-tuned, we hypothesize that they are under tight mechanical-structural control to ensure an ecologically optimized seed release upon environmental conditions suitable for wind dispersal. In this context, we propose an interplay of humidity and temperature to be the external "drivers" for the initial cone opening, in which resin works as a crucial chemical-mechanical latch system.
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Affiliation(s)
- Martin Horstmann
- Botanic Garden, Plant Biomechanics Group, University of Freiburg, Freiburg im Breisgau, Germany
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, Bochum, Germany
| | - Hannah Buchheit
- Freiburg Materials Research Center and Institute for Macromolecular Chemistry, University of Freiburg, Freiburg im Breisgau, Germany
| | - Thomas Speck
- Botanic Garden, Plant Biomechanics Group, University of Freiburg, Freiburg im Breisgau, Germany
- Cluster of Excellence livMatS, University of Freiburg, Freiburg im Breisgau, Germany
| | - Simon Poppinga
- Department of Biology, Botanical Garden, Technical University of Darmstadt, Darmstadt, Germany
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Zhang Y, Zhang C, Wang R, Tan W, Gu Y, Yu X, Zhu L, Liu L. Development and challenges of smart actuators based on water-responsive materials. SOFT MATTER 2022; 18:5725-5741. [PMID: 35904079 DOI: 10.1039/d2sm00519k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Water-responsive (WR) materials, due to their controllable mechanical response to humidity without energy actuation, have attracted lots of attention to the development of smart actuators. WR material-based smart actuators can transform natural humidity to a required mechanical motion and have been widely used in various fields, such as soft robots, micro-generators, smart building materials, and textiles. In this paper, the development of smart actuators based on different WR materials has been reviewed systematically. First, the properties of different biological WR materials and the corresponding actuators are summarized, including plant materials, animal materials, and microorganism materials. Additionally, various synthetic WR materials and their related applications in smart actuators have also been introduced in detail, including hydrophilic polymers, graphene oxide, carbon nanotubes, and other synthetic materials. Finally, the challenges of the WR actuator are analyzed from the three perspectives of actuator design, control methods, and compatibility, and the potential solutions are also discussed. This paper may be useful for the development of not only soft actuators that are based on WR materials, but also smart materials applied to renewable energy.
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Affiliation(s)
- Yiwei Zhang
- School of Automation and Electrical Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning, China.
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
| | - Chuang Zhang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
| | - Ruiqian Wang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjun Tan
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanyu Gu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China
| | - Xiaobin Yu
- School of Automation and Electrical Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning, China.
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
| | - Lizhong Zhu
- School of Automation and Electrical Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning, China.
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
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Tulska E, Aniszewska M, Gendek A. The Kinematics of Scale Deflection in the Course of Multi-Step Seed Extraction from European Larch Cones ( Larix decidua Mill.) Taking into Account Their Cellular Structure. MATERIALS 2021; 14:ma14174913. [PMID: 34501003 PMCID: PMC8434191 DOI: 10.3390/ma14174913] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 11/23/2022]
Abstract
The objective of the study was to elucidate the kinematics of cone opening in the European larch (Larix decidua Mill.) during a four-step seed extraction process and to determine optimum process time on that basis. Each step lasted 8 h with 10 min of water immersion between the steps. The study also described the microscopic cellular structure of scales in cones with a moisture content of 5% and 20%, as well as evaluated changes in cell wall thickness. The obtained results were compared with the structural investigations of scales conducted using scanning electron microscopy (SEM) of characteristic sites on the inner and outer sides of the scales. The greatest increment in the scale opening angle was noted on the first day of the process (34°) and in scales from the middle cone segment (39°). In scales with a moisture content of 5% and 20%, the greatest changes in cell wall thickness were recorded for large cells (57%). The inner and outer structure of scales differed in terms of the presence and size of cells depending on the moisture content of the cones (5%, 10%, or 20%). The study demonstrated that the moisture content of cones was the crucial determinant of the cellular structure and opening of scales in larch cones. The scale opening angle increased with decreasing moisture content but did not differ significantly for various segments of cones or various hours of the consecutive days of the process. This finding may lead to reducing the seed extraction time for larch cones. The internal and external structure of scales differed depending on moisture content, which also determined the size and wall thickness of cells.
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