Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu Esq, Cda. Miguel Stampa s/n, 07738, Gustavo A. Madero, Ciudad de México, Mexico.
Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional, Luis Enrique Erro s/n, Zacatenco, 07738, Gustavo A. Madero, Ciudad de México, Mexico.
Plant Physiol Biochem. 2018 Nov;132:566-570. doi: 10.1016/j.plaphy.2018.10.008. Epub 2018 Oct 10.
The morphology and micromechanical properties of the mineral crystals embedded in the pecan nutshell (Carya illinoinensis) were characterized. Qualitative and quantitative morphological analyses carried out revealed that the crystals were comprised of calcium oxalate (CaOx) and have a wide range of sizes, with prismatic shapes, distributed heterogeneously in the sclerenchyma tissue. From indentation tests, it was found that CaOx crystals are stiffer structures compared to stone cells (sclerenchyma tissue), showing hardness and elastic modulus values of 0.53 ± 0.19 GPa and 9.4 ± 1.80 GPa, respectively. Additionally, the values of fracture toughness (0.08 ± 0.02 MPa m) and the brittleness index (9336 m) revealed that these types of structures are extremely brittle. The results obtained suggest that the main function of the CaOx crystals is to provide structural support to tissue. The presented methodology demonstrates the potential of the instrumented indentation technique (IIT) for in situ micromechanical characterization of mineral crystals located in plant tissues.
对嵌入山核桃壳（Carya illinoinensis）中的矿物晶体的形态和微观力学性能进行了表征。定性和定量形态分析表明，这些晶体由草酸钙（CaOx）组成，具有广泛的尺寸范围，呈棱柱形，在厚壁组织中不均匀分布。从压痕测试中发现，与石细胞（厚壁组织）相比，CaOx 晶体是更硬的结构，其硬度和弹性模量值分别为 0.53±0.19 GPa 和 9.4±1.80 GPa。此外，断裂韧性（0.08±0.02 MPa·m）和脆性指数（9336 m）的值表明这些类型的结构极脆。研究结果表明，CaOx 晶体的主要功能是为组织提供结构支撑。所提出的方法证明了仪器压痕技术（IIT）在原位植物组织中矿物晶体的微观力学特性表征方面具有潜力。
