Water Uptake in the Soil

• Water enters the root hair cell across its partially permeable membrane by osmosis from the hypotonic solution surrounding the soil particles, to the hypertonic solution inside the root hair cytoplasm (down a water potential gradient)
• The root hair cell maintains the high tonicity (the hypertonic environment) by active uptake of mineral ions such as Mg^2^+ and NO_3^- from the surrounding soil using carrier proteins embedded in the root hair cell plasma membrane