It is thought that the microfibril contains a single elementary fibril surrounded by hemicel — luloses (see Figure 3.9). The dimensions of microfibrils determined by electron microscopy, and recently by AFM, range from 2 to 3 nm to 20 to 50 nm (13). This apparent size vari­ation of the microfibrils may be due to the different plant species and tissue types, but is more likely due to the sampling errors and inaccurate measurements made using imag­ing techniques with limited resolution. Current biochemical evidence has shown similar biosynthesis mechanisms (e. g., highly gene homology) for all higher plants (14). There is no evidence to suggest that the elementary fibril is synthesized differently among higher plant species. In contrast, the microfibrils are dynamic structures that could be modified post-formation depending on their interaction with the matrix polymers. The diameter of the microfibrils could be different for different tissues, different cell wall types, or even for different cell wall lamellae.