Microtubule Component of the cell cytoskeleton made of tubulin, a component of the mitotic spindle, and a player in the orientation of cellulose microfibrils in the cell wall.

• 质外体：是一个开放性的连续自由空间，包括细胞壁、细胞间隙及导管等。胞间连丝：是贯穿胞壁的管状结构物，内有连丝微管，其两端与内质网相连接。