Résumé
The mechanism responsible for unusual mechanical properties of tension wood gelatinous fiber (G-fiber) was investigated. We discussed origins of high tensile growth stress, high drying shrinkage, and rapid increase of Young's modulus due to drying, in association with microscopic structure of gelatinous layer (G-layer). Anatomical, crystallographic, and micromechanical approaches were employed. As the result, it is cleared that G-layer structure as hydro-gel has a key to understand hygromechanical properties in the tension wood G-fiber. The origin of contractive force in maturing G-layer is still unknown, however, the structure and behavior of the swollen hydro-gel may give some key to solve it.