BSCI 207 Lecture Notes - Lecture 21: Electrochemical Gradient, Root Hair, Nitrogen Fixation
21 Oct 2016
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Plants require elements and minerals that cannot be made by itself. Plants require both macronutrients and micronutrients: fixed nitrogen, potassium, and phosphorus are macromolecules that are also. Growth limiting nutrients : micronutrients are almost all metal ions. Allows the breaking of bonds that amino acids cannot do by itself. Soil originated from the gradual breaking down of rock by erosion over a very long period: small fragments of rock give soil the property to hold water. It is difficult for the plant to absorb nutrients: cationic molecules are bound to the negatively charges soil particles and are not actually in solution, concentration of minerals outside the plant is less than that inside the cell. Simple diffusion will not work: solution: Plants release protons into the water surrounding the root hairs. Neutralizes soil particle charge and frees cations for absorption. Key minerals are ions and are hydrophilic.
