Periodic Reporting for period 4 - SCATAPNUT (Scattering and tapping on soft-hard-open nuts)
Periodo di rendicontazione: 2021-03-01 al 2021-08-31
To understand the different functionalities of nut shells we had to dive deep into the micro-and nanostructure of these sclerenchyma tissues and their chemistry by state-of-the-art methods. Sclerenchyma derives etymologically from the Greek word sklērós (= ‘hard’), indicating that hardness is a central feature. We wanted to understand the properties of the hard nutshells, but also elucidate the “production process” from the soft to the hard state by including samples from different developmental stages. To derive general and specific design principles of the nutshells and structure-function relationship we investigated and compared different nut species.
Understanding these packaging concepts of plants, will inspire biomimetic material approaches as well as the use of nutshells for new biomaterial developments. Nutshells will be available in increasing amounts as waste, because nuts are more and more recognized as valuable, healthy natural food resources.
To understand the formation of the nutshells, from isodiametric to polylobate and from soft to hard, we sampled walnut at different time points from catkin-formation (May) to harvest (October). By serial block face-scanning electron microscopy, Raman and fluorescence microscopy we found the secrets behind shape formation: multiple loops of cellulosic thickenings in cell walls, act as stiff restrictions during cell growth and leading to the lobed cell shape (Antreich et al. 2021). After shape morphogenesis the transformation from the soft to the hard state is fulfilled by adding cell wall material and impregnating with hydrophobic polymers (lignin) and aromatic components (Xiao et al. 2020). The cell wall is added continuously in layers and could be visualized as helicoidal deposition of cellulose fibrils (Xiao et al. 2021). The suture, the line along which the seedling will push the nut apart, shows different composition (high pectin content) and by this different swelling properties to achieve the opening (Xiao et al. in preparation).
Results have been published in multidisciplinary, material science and plant journals with high impact and have been picked up by several news outlets. Elucidating these packaging concepts of plants, will inspire biomimetic material approaches as well as the use of nutshell waste for sustainable material solutions.
5 most important publications
Antreich, SJ; Xiao, N; Huss, JC; Horbelt, N; Eder, M; Weinkamer, R; Gierlinger, N;
The Puzzle of the Walnut Shell: A Novel Cell Type with Interlocked Packing. Advanced Science. 2019; 6(16):1900644
Altmetric 130: blogged by 3, picked up by 12 news outlets, tweeted by 17, on 1 facebook page
Xiao, NN; Felhofer, M; Antreich, SJ; Huss, JC; Mayer, K; Singh, A; Bock, P; Gierlinger, N
Twist and lock: nutshell structures for high strength and energy absorption. ROY SOC OPEN SCI. 2021; 8(8), 210399
Altmetric 107: blogged by Science, picked up by 7 news outlets, tweeted by 53
Huss, JC; Antreich, SJ; Bachmayr, J; Xiao, N; Eder, M; Konnerth, J; Gierlinger, N; Topological Interlocking and Geometric Stiffening as Complementary Strategies for Strong Plant Shells..
Advanced Materials. 2020; 32(48):e2004519
Altmetric 37: picked up by 1 news outlets, tweeted by 35, on 1 facebook page
Huss, JC; Gierlinger, N; .(2021): Functional packaging of seeds. New Phytologist. 2021; 230(6):2154-2163
Altmetric 25: blogged by 1, tweeted by 31, on 1 facebook page
Antreich, SJ; Xiao, N; Huss, JC; Gierlinger, N; A belt for the cell: cellulosic wall thickenings and their role in morphogenesis of the 3D puzzle cells in walnut shells.. J Exp Bot. 2021; 72(13):4744-4756
Altmetric 9: tweeted by 14
1) We developed in-situ methods for in-depth characterization of seed dispersal units at the micro-and nano level: native sample preparation by cryo-microtomy, Atomic force microscopy to reveal nanostructure and mechanics, Raman imaging for microchemistry (database of vibrational spectra and multivariate data analysis approaches), X-ray tomography, fluorescence microscopy and serial block face electron microscopy for cell shape elucidation, mechanical testing and investigation of fracture surfaces by scanning electron microscopy to draw conclusions on mechanical performance.
2) We revealed the heterogeneity and common design principles by including different biological species and derived general structure-function relationships (see above).
3) We followed in-situ morphogenesis and maturation of seed coats and highlighted the selective deposition of cellulose fibrils to achieve cell shaping and impregnation with aromatic components to waterproof the final mature nutshell.