<<–2/”>a href=”https://exam.pscnotes.com/5653-2/”>p>xylem and phloem, incorporating the requested Elements:
Introduction
In the intricate world of plant vascular systems, xylem and phloem emerge as the key players responsible for transportation. Xylem, primarily a conduit for water and dissolved Minerals, ascends from the roots to the rest of the plant. In contrast, phloem, a Network of living cells, facilitates the downward movement of sugars produced in leaves (through Photosynthesis) to other plant parts.
Key Differences Between Xylem and Phloem (Table Format)
| Feature | Xylem | Phloem |
|---|---|---|
| Primary Function | Transport of water and dissolved minerals from roots to leaves. | Transport of sugars (photosynthates) from leaves to other plant parts. |
| Direction of Flow | Unidirectional (upward). | Bidirectional (both upward and downward). |
| Cell Types | Tracheids, vessel elements (both dead at maturity), xylem parenchyma (living). | Sieve tube elements (living), companion cells, phloem parenchyma, phloem fibers. |
| Cell Wall | Thickened with lignin (provides structural support). | Thin, primarily composed of cellulose. |
| Maturity | Mostly dead cells (except for xylem parenchyma). | Living cells. |
| Energy Requirement | Passive transport (does not require energy). | Active transport (requires energy). |
Advantages and Disadvantages of Xylem and Phloem
| Tissue | Advantages | Disadvantages |
|---|---|---|
| Xylem | – Provides structural support to the plant. | – Susceptible to cavitation (formation of air bubbles) under Stress. |
| – Efficient transport of water and minerals over long distances. | – Limited capacity for storage. | |
| Phloem | – Transports essential sugars to all parts of the plant, supporting Growth and development. | – Vulnerable to pests and diseases that can disrupt sugar flow. |
| – Bidirectional flow allows for flexible resource allocation. | – Transport is energy-intensive. |
Similarities Between Xylem and Phloem
- Both are complex Tissues composed of multiple cell types.
- Both form continuous networks throughout the plant body.
- Both are essential for plant survival and growth.
FAQs on Xylem and Phloem
1. Can xylem and phloem regenerate if damaged?
- Xylem: Some Plants can form new xylem tissue, but extensive damage can be detrimental.
- Phloem: Limited regeneration is possible, but severe damage often leads to impaired growth.
2. What factors affect the rate of transport in xylem and phloem?
- Xylem: Temperature, humidity, Soil water availability, plant Transpiration rate.
- Phloem: Concentration gradients of sugars, metabolic activity of the plant, temperature.
3. How do herbicides affect xylem and phloem?
- Some herbicides target specific ENZYMES involved in phloem transport, disrupting sugar flow and leading to plant death.
4. Can xylem and phloem be seen with the naked eye?
- In some plants, larger veins containing xylem and phloem bundles may be visible, especially in leaves. However, microscopic examination is needed to observe individual cells.
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