BIO-8 Lecture Notes - Lecture 7: Semipermeable Membrane, Field Capacity, Osmotic Pressure
Document Summary
Section 1: most terrestrial plants obtain nutrients and water from the soil. Plants need oxygen, carbon, and hydrogen to fuel survival and growth. Plants also require other inorganic nutrients including nitrogen, phosphorus, calcium, and potassium to make proteins, nucleic acids, and other essential compounds. Many nutrients are obtained as ions dissolved in water held by the soil. Nutrients come in various forms, such as ammonia (nh4+) , nitrate (no3-), phosphate (po43-), calcium (ca2+), and potassium (k+) The availability of these ions varies with soil temp, ph, and the presence of other ions. Water potential: a measure of water"s potential energy; affects the movement of water in soil from one location to another. Matric (or matrix) potential: the potential energy generated by the attractive forces between water molecules and soil particles; occurs bc water molecules and soil particles have electrical charges. Matric potential is quantified in units of pressure, called megapascals.
