Which of the following is/are the main absorbing organ/organs of plants?
Root only
Understanding Plant Absorption: Roots are Key
Plants are amazing organisms that need water and nutrients to grow and survive. They get most of these essential substances from their surroundings, primarily from the soil. Different parts of a plant have different jobs. The question asks about the main organ responsible for absorbing water and minerals.
Role of Roots in Plant Absorption
The roots are typically found underground. Their main functions include anchoring the plant, storing food, and, crucially, absorbing water and dissolved mineral salts from the soil. Roots have a large surface area, further increased by tiny extensions called root hairs. These root hairs are microscopic and numerous, greatly enhancing the ability of the root system to soak up water and minerals from the soil particles.
- Roots grow downwards into the soil, seeking out water.
- Root hairs increase the contact area with the soil.
- Water enters the root by osmosis, and minerals enter by active transport or diffusion.
Functions of Other Plant Parts
Let's briefly consider the roles of other parts mentioned in the options:
- Leaves: Leaves are the primary sites of photosynthesis, where plants make their food using sunlight, water, and carbon dioxide. They absorb carbon dioxide gas from the atmosphere through tiny pores called stomata. While some minor absorption of water or nutrients can occur through the leaf surface (cuticle or stomata), this is not the main way plants absorb water and minerals, especially those from the soil. Leaves are mainly involved in gas exchange and transpiration (loss of water vapor).
- Bark: Bark is the tough, protective outer layer of the stems and roots of woody plants. Its main function is protection against physical damage, insects, and diseases. Bark is not primarily involved in the absorption of water and minerals from the soil or air.
Analyzing the Options
Let's evaluate the given options based on the primary functions of plant organs:
- Root only: This option suggests that the root is the only main absorbing organ. As discussed, roots are the primary structures responsible for absorbing water and minerals from the soil due to their structure, location, and specialized root hairs. This aligns well with the main absorption process for these substances.
- Leaf only: This option claims only the leaf is the main absorbing organ. This is incorrect because while leaves absorb CO\(_{2}\) for photosynthesis and some foliar absorption is possible, they are not the main organs for absorbing water and minerals from the soil.
- Root and leaf only: This option includes both root and leaf. While roots are the main absorbing organs for soil water and minerals, including leaves as a *main* absorbing organ for these substances is generally inaccurate when considering the plant's primary source of water and nutrients from the soil.
- Root, leaf and bark: This option includes root, leaf, and bark. As explained, bark is not an absorbing organ, and leaves are not the main absorbing organ for soil water and minerals. Therefore, this option is incorrect.
Considering the primary mechanism by which plants absorb water and minerals from the soil, the roots are the main organs responsible. Therefore, the option that highlights roots as the primary absorbing structure is the most accurate.
Conclusion on Plant Absorption
The main absorbing organs of plants, specifically for water and mineral nutrients from the soil, are the roots. Their structure, particularly the presence of root hairs, is perfectly adapted for this crucial function.
| Plant Part | Primary Absorption Role | What is Absorbed? |
|---|---|---|
| Root | Main absorption from soil | Water and dissolved minerals |
| Leaf | Absorption from air (main) or minor foliar absorption | Carbon dioxide (CO\(_{2}\)), some atmospheric water/nutrients |
| Bark | Protection | Minimal to no absorption |
Revision Table: Plant Organ Functions
| Plant Organ | Key Functions |
|---|---|
| Root | Anchorage, absorption of water/minerals, storage |
| Stem | Support, transport (water, nutrients, sugars), storage |
| Leaf | Photosynthesis, gas exchange, transpiration |
| Flower | Reproduction |
| Fruit | Seed dispersal, protection |
| Seed | Reproduction, dispersal |
Additional Information on Root Absorption
Root absorption involves two main pathways for water movement: the apoplast pathway (water moves through cell walls and intercellular spaces) and the symplast pathway (water moves through the cytoplasm of cells connected by plasmodesmata). The casparian strip in the endodermis of the root acts as a barrier, forcing water in the apoplast pathway into the symplast pathway before entering the vascular tissue (xylem), ensuring that all absorbed substances pass through at least one cell membrane for regulation.
Mineral ions are absorbed by roots through active transport (requiring energy) or diffusion, depending on their concentration gradient and the plant's needs. This absorption primarily occurs in the root hair zone.
Similar Questions
Under the Kingdom Plantae, which of the following individuals are predominantly aquatic?
Which one of the following denotes a ‘true’ fruit?
Which one of the following statements about phloem is correct?
Mature sclerenchyma cells have _______.
Which one of the following is active transport?
Chlorophyll in photosynthetic prokaryotic bacteria is associated with ________.
Marsilea, Fern and Horse-tail are examples of which one of the following plant groups?
Which one of the following tissues is responsible for increase of girth in the stem of a plant?
Which one of the following organisms is dependent on saprophytic mode of nutrition?
Which of the following is not a primary function of a green leaf?
Important Questions from Botany
Which of the following is a type of nutrition?
I. Heterotrophic
II. Autotrophic
Which of the following are the 5 groups that plants are divided into?
Fungi are always
In which of the following plants root is the food storage organ?
Which of the following does NOT form an essential part of the process of photosynthesis?
