The growth and development of plants solely depend on the available nutrients in the soil. Mainly plant roots absorb these essential nutrients and transport them to different parts of the plants for carrying out several functions.
Mechanism of nutrient transport to plants follows certain ways for optimum absorption, depending on the soil types. Sixteen minerals are necessary for plant growth. Root hairs absorb thirteen of them. These minerals include nitrogen, magnesium, potassium, phosphorus, calcium, sulphur, etc. These six essential minerals are called micronutrients.
Mineral Nutrients Transportation
Uptake of water and minerals by roots, reach to each portion of the plants in two methods.
Active Method
This mechanism of nutrient transport to plants happens with the help of the metabolic energy of plant cells. This process depends on the movement of ions from outer cells to inner cells and vice-versa.
There are several methods through which mineral transport to plants.
Root Interception- Soil particles are of different sizes, contain all the nutrients in them and form soil aggregators. But most plants cannot reach the large surface of soil aggregates. Roots grow around those aggregators and not in them. Therefore only a limited quantity of minerals can come in direct contact of root hairs. For this matter, root interception is not the most useful mechanism of nutrient transportation.
Mass Flow- Plants lose water through leaves and the process is called transpiration. To compensate for the loss, roots take up water from the soil. Soil water usually consists of three negatively charged sulphate, nitrate and borate ions. Since roots cannot absorb soil waters completely, these mineral ions cannot reach the root. Therefore the quantity of these three nutrients that reaches the root surface through mass flow is variable. It is an essential mechanism of nutrient transport to plants.
Diffusion- Plants physiologists proved that the root surface of plants is of lower concentration. The soil aggregators also combine a few positively charged nutrients like Ca++, K+, and Mg++. Also, the surface of soil aggregators is of higher concentration. Therefore these ions travel to roots through the process of diffusion. The uptake of mineral ions against the concentration gradient plays a vital role in plants.
Passive Method
This method of nutrient absorption takes place without the direct interference of metabolic energy.
Phloem Transport
Apart from these two significant methods, there is also another method that helps to transport food and minerals from leaves to other parts of plants. After the synthesis of food in leaves, it takes the form of sucrose to travel to other cells through Phloem tissues.
This transportation occurs from source to stick. Also, the movement of phloem transport is bidirectional. For example, in early spring, the food travels from roots to new buds in an upward direction. Minerals absorbed by roots move to the leaf through numerous pipe-like vessels.
Importance of Mineral Nutrients
Both macro and micronutrients are equally essential for plants for the following reasons.
Balance osmotic pressure.
Helps in chlorophyll production.
Enhances the quality of fruits and seeds.
Boosts overall growth of plants.
Reduces the occurrence of plant diseases.
Balances pH level of root saps.
Improves protein production.
Fastens root growth and fruit ripening.
All the mechanism of nutrient transport to plants aids in maintaining the overall health of it.
Multiple Choice Questions
1. Transport of food in high plants occur through
Tracheids
Transfusion tissue
Sieve elements
Companion cells
2. Which of the following requires ATP energy?
Facilitated transport
Active transport
Simple diffusion
All of these
Answers: 1-d), 2-b).
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FAQs on Transport of Mineral Nutrients
1. What is the primary way mineral nutrients are transported throughout a plant?
The primary long-distance transport of mineral nutrients occurs through the xylem tissue. After being absorbed by the roots, minerals are dissolved in water and carried upwards to the stem, leaves, and other parts of the plant along with the flow of water in the transpiration stream.
2. What are some essential mineral ions that plants need to absorb from the soil?
Plants need various mineral ions for healthy growth and metabolic functions. According to the CBSE syllabus for the 2025-26 session, key examples include:
- Nitrates (NO₃⁻), which are crucial for producing amino acids and proteins.
- Phosphates (H₂PO₄⁻), essential for forming ATP and nucleic acids like DNA.
- Potassium (K⁺), which acts as an enzyme activator and regulates the opening and closing of stomata.
- Magnesium (Mg²⁺), which is a central atom in the chlorophyll molecule, vital for photosynthesis.
3. How does active transport help in the uptake of mineral ions by roots?
Active transport is essential because the concentration of minerals in the soil is often much lower than inside the root cells. Root cells use metabolic energy, in the form of ATP, to power protein pumps that move ions into the root against their concentration gradient. This ensures the plant can accumulate the required amount of nutrients even from nutrient-poor soil.
4. What is the difference between the apoplast and symplast pathways for mineral transport in roots?
The apoplast and symplast are two distinct routes minerals can take to move from the root surface to the xylem:
- The apoplast pathway is a non-living route where water and minerals move through the spaces between cell walls. It is a faster path but is blocked at the endodermis by the Casparian strip.
- The symplast pathway is a living route where minerals enter the cytoplasm of a root cell and move from one cell to the next through cytoplasmic connections called plasmodesmata. This pathway allows for selective uptake.
5. Why can't plants rely on passive diffusion alone to absorb mineral ions?
Plants cannot depend solely on passive diffusion for two main reasons. First, minerals exist as charged ions in the soil, and these ions cannot easily pass through the non-polar lipid bilayer of the cell membrane. Second, the concentration of essential minerals is typically higher inside the root cells than in the soil. Therefore, energy is required to move these ions against their concentration gradient, which necessitates active transport.
6. What is the role of the Casparian strip in mineral nutrient transport?
The Casparian strip is a band of waterproof, waxy material (suberin) in the walls of the endodermal cells of the root. Its primary role is to act as a barrier, blocking the apoplastic pathway. This forces water and dissolved minerals to pass through the cell membrane and enter the symplast pathway, giving the plant selective control over which minerals enter the xylem and are transported to the rest of the plant.
7. How does the transpiration pull mechanism assist in moving minerals to the leaves?
The transpiration pull is the negative pressure or tension created in the xylem as water evaporates from the leaves. This suction force pulls the entire column of water up from the roots. Since mineral ions are dissolved in this water, they are effectively carried along for the ride. This process is a major driving force for the mass flow of minerals over long distances within the plant, requiring no metabolic energy from the plant for the movement itself.
8. Are minerals only transported upwards in the xylem?
No. While the initial transport from roots to leaves happens in the xylem, minerals can be moved again to different parts of the plant through the phloem. This process is known as remobilisation. For example, as leaves get older, essential nutrients like nitrogen, phosphorus, and potassium are often broken down and transported via the phloem to younger, actively growing areas like new leaves, flowers, or seeds.
9. What would be the consequence if a plant's endodermis was damaged?
If the endodermis and its Casparian strips were damaged, the plant would lose its ability to regulate the uptake of water and minerals. It would lose the crucial checkpoint that forces substances into the selective symplastic pathway. This could lead to an uncontrolled, non-selective flow of solutes into the vascular system, potentially allowing toxic substances to enter and disrupting the mineral balance required for the plant's survival.
