● Much of the studies on `color{violet}"mechanism of absorption"` of elements by plants has been carried out in `color{violet}"isolated cells, tissues or organs"`.

● These studies revealed that the `color{violet}"process of absorption"` can be demarcated into `color{Brown}"two main phases."`

● In the `color{violet}"first phase"`, an initial `color{violet}"rapid uptake of ions"` into the ‘free space’ or ‘outer space’ of cells – the `color{Brown}"apoplast"`, is `color{violet}"passive"`.

● In the `color{violet}"second phase"` of uptake, the ions are `color{violet}"taken in slowly"` into the ‘inner space’ – the `color{Brown}"symplast"` of the cells.

● The `color{violet}"passive movement"` of ions into the `color{violet}"apoplast"` usually occurs through `color{Brown}"ion-channels"`, the trans-membrane proteins that function as `color{violet}"selective pores"`.

● On the other hand, the `color{violet}"entry or exit of ions"` to and from the `color{violet}"symplast"` requires the expenditure of `color{Brown}"metabolic energy"`, which is an process.

● The `color{violet}"movement of ions"` is usually called the inward movement into the cells is `color{Brown}"influx"` and the outward movement, `color{Brown}"efflux"`.

● Mineral salts are `color{violet}"translocated through xylem"` along with the `color{violet}"ascending stream"` of water, which is pulled up through the plant by `color{violet}"transpirational pull"`.

● Analysis of `color{violet}"xylem sap"` shows the presence of `color{violet}"mineral salts"` in it.

● Use of `color{violet}"radioisotopes of mineral elements"` also substantiate the view that they are `color{violet}"transported"` through the `color{violet}"xylem"`.

● `color{violet}"Majority of the nutrients"` that are essential for the `color{violet}"growth and development"` of plants become available to the roots due to `color{violet}"weathering and breakdown"` of rocks.

● These processes enrich the soil with `color{violet}"dissolved ions"` and `color{violet}"inorganic salts"`.

● Since they are `color{violet}"derived from the rock minerals"`, their role in plant nutrition is referred to as `color{Brown}"mineral nutrition"`.

● Soil consists of a `color{violet}"wide variety"` of substances.

● Soil not only supplies `color{violet}"minerals"` but also harbours `color{violet}"nitrogen-fixing bacteria"`, other microbes, holds water,
supplies air to the roots and acts as a matrix that stabilises the plant.

● Since deficiency of `color{violet}"essential minerals"` affect the crop-yield, there is often a need for supplying them through `color{violet}"fertilisers"`.

● Both `color{violet}"macro-nutrients"` (N, P, K, S, etc.) and `color{violet}"micro-nutrients"` (Cu, Zn, Fe, Mn, etc.) form components of `color{violet}"fertilisers"` and are applied as per need.