To maintain or adjust posture under the challenges of gravity and increased self-weight, or the effects of light, snow, and slope, plants have the ability to develop a special type of tissue called reaction tissue. The formation of reaction tissue is a result of plant evolution and adaptation. The identification and study of plant reaction tissue are of great significance for understanding the systematics and evolution of plants, the processing and utilization of plant-based materials, and the exploration of new biomimetic materials and biological templates. Trees' reaction tissues have been studied for many years, and recently, many new findings regarding these tissues have been reported. However, reaction tissue requires further detailed exploration, particularly due to their complex and diverse nature. Moreover, the reaction tissues in gymnosperms, vines, herbs, etc., which display unique biomechanical behavior, have also garnered the attention of research. After summarizing the existing literature, this paper provides an outline of the reaction tissues in woody plants and non-woody plants, and lays emphasis on alternations in the cell wall structure of the xylem in softwood and hardwood. The purpose of this paper is to provide a reference for the further exploration and study of reaction tissues with great diversity.
Keywords: compression wood; gelatinous fibers; growth stress; reaction tissue; tension wood.