i. The examination of plant ash reveals the absorption of minerals by plants from the soil and their surroundings.
ii. Plants absorb minerals primarily in the ionic (dissolved) form through their roots, and subsequently, these minerals are transported within the plant.
iii. The absorption of mineral ions operates independently of water absorption.
iv. Mineral ion absorption can occur through two mechanisms: active and passive absorption.
v. In passive absorption, mineral ions move into root cells through diffusion – a process where ions move from an area of higher concentration to lower concentration without the utilization of energy.
vi. Since most minerals in the soil are charged particles and cannot easily pass through cell membranes, the majority of minerals are actively absorbed, involving energy expenditure.
vii. In active absorption, minerals are taken up against the concentration gradient with the consumption of energy.
viii. Absorbed mineral ions are pulled upward along with xylem sap due to transpiration pull.
ix. Consequently, mineral ions are drawn from the source (roots) and transported upwards through the sap to various areas, including apical and lateral regions, young leaves, developing flowers, fruits, seeds, and storage organs.
x. Unloading of mineral ions occurs near cells through diffusion along fine veins, and cells actively uptake them.