Mechanical Testing of Tomato Plant Stem in Relation to Structural Composition

Abstract

As an important biological resource, the development and utilization of tomato plant stem arouse more and more attention. Facing increasingly rare resources and serious environmental protection, it will have more significant meaning to comprehensively use stem resource and research its mechanical properties. This paper takes tomato plant stem as research object to observe and analyze the microstructure of the fibers, and test moisture, tensile and shear mechanical properties of different parts of stem. The results revealed that: (1) Tomato plant stem is a composite material and its microstructure mainly consists of epidermis, cortex, vascular bundle and pith; moreover, it presents on sieve texture with heterogeneous distribution. (2) Cross-sectional area of root is 7.08–23.4 mm2, its tensile strength and shear strength are 8.64–17.92 and 4.12–5.26 MPa, respectively, while cross-sectional area of middle is 5.94–20.19 mm2 with tensile strength and shear strength being 13.73–22.68 and 2.24–4.38 MPa separately; in terms of top part, its cross-sectional area is between 5.04 and 14.57 mm2 with tensile strength and shear strength being 11.86–29.59 and 1.4–4.27 MPa. (3) All tensile stress, tensile strength and elastic modulus from root to top part tend to decrease gradually; in addition, different parts have significant influence on both tensile strength and elastic modulus. (4) Shear stress, shear strength and shear modulus from root to top reduced gradually; besides, each part has extremely obvious impact on shear strength and shear modulus. This research provides necessary experimental data and theoretical basis for the development of harvest and processing machinery for tomato plant stems; moreover, it helps to confirm working parameters when cutting and assists to accelerate the application and promotion of comprehensive utilization of tomato plant stem.