Summary of Absorption Process.
Soil particles are negatively charged particles, while minerals are positively charged ions in the soil that are attracted to soil because they have opposite charges. Aluminum is a harmful mineral that essentially disrupts membranes, causing them to lose the ability to transfer materials. The most pertinent effect of aluminum is it causes the region of elongation to lose the ability to absorb water, disenabling the plant to grow. In order to try and keep aluminum out, root hairs, which selectively absorb minerals based on their shape, size, or charge contain transporter proteins that have a specifically shaped protein that matches all the beneficial minerals a plant can absorb. After this first check point in a plant the plasmodesmata also is selective to make sure that what is going through is beneficial, preventing aluminum from reaching the vascular cylinder. Just before the vascular cylinder lies the endodermis, the ultimate blocking point, which is made of suberin and prevents molecules from squeezing through the cells and forces them to go through the "face". Although aluminum can still squeeze between two cells through intercellular spaces, it cannot penetrate through the endoermis unless there is a large concentration of it.