Two plants structures that provide structural support to plants are Sclerencyma and collenchyma.
The collenchyma tissue is made up of cells that are elongated in nature which have thickened cell walls. This tissue is found next to growing tissue and provides support as required like in the growth of stems and in branches. The tissue can alter its properties based on the environmental requirements, for example when the wind is strong this can grow thicker than usual.
Sclerencyma consists of two categories of tissue called fibers and sclereids. These cells are composed of cellulose, hemicellulose and lignin that helps in the process of providing support. These cells die after cellular elongation though they continue to provide support as dead structural tissue in plants.