Mineral ions: magnesium and nitrateSpec 2.22
Plants need more than carbon dioxide, water and light. They also need mineral ions for healthy growth. The roots absorb these ions from the soil. You need to know two of them.
| Mineral ion | Why the plant needs it | Effect of a shortage |
|---|---|---|
| Magnesium ions | Needed to make chlorophyll | Leaves turn yellow, because there is less chlorophyll |
| Nitrate ions | Needed to make amino acids, which are joined to make proteins for growth | Stunted (poor) growth |
Without enough chlorophyll, a plant absorbs less light, so it photosynthesises more slowly and makes less glucose. Without enough amino acids, the plant cannot make the proteins it needs for new cells, so it grows slowly.
(opens full size in a new tab)Common mistake:
Link each ion to its job: magnesium goes with chlorophyll (yellow leaves), nitrate goes with amino acids and proteins (stunted growth). Do not say that plants use nitrate to make chlorophyll or glucose.