(a) Diffusion and Osmosis
| Diffusion | Osmosis |
| 1. Diffusion is the passive movement of particles, ions, and molecules along the concentration gradient. | 1. Osmosis is the process in which the diffusion of a solvent (water) occurs across a semi-permeable membrane. |
| 2. It can occur in solids, liquids, and gases. | 2. It occurs in the liquid medium. |
| 3. It does not require a semi-permeable membrane. | 3. It requires a semi-permeable membrane. |
(b) Transpiration and Evaporation
| Transpiration | Evaporation |
| 1. It occurs in plants. | 1. It occurs from any free surface and involves living and non-living surfaces.
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| 2. It is a physiological process. | 2. It is a physical process.
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| 3. It occurs mainly through the stomatal pores on plant leaves. | 3. It is occurs through any free surface.
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| 4. It is controlled by environmental factors as well as physiological factors of plants such as root-shoot ratio and number of stomata. |
4. It is entirely driven by environmental factors. |
(c) Osmotic pressure and Osmotic potential
Osmotic pressure
| Osmotic potential |
1. It is expressed in bars with a positive sign.
| 1. It is expressed in bars with a negative sign.
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| 2. It is a positive pressure. | 2. It is a negative pressure. |
| 3. Its value increases with an increase in the concentration of solute particles. | 3. Its value decreases with an increase in the concentration of solute particles. |
(d) Imbibition and Diffusion:
Imbibition
| Diffusion |
1. Imbibition is a special type of diffusion. In this process, water is absorbed by solids and colloids, causing an enormous increase in volume.
| 1. Diffusion is the passive movement of particles, ions, and molecules along the concentration gradient.
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2. It usually involves water.
| 2. It involves solids, liquids, and gases. |
(e) Apoplast and Symplast pathways of water in plants
Apoplast pathway
| Symplast pathway
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1. The apoplast pathway involves the movement of water through the adjacent cell walls of the epidermis and cortex. The movement of water is restricted at the casparian strips of the root endodermis.
| 1. The symplast pathway involves the movement of water through the interconnected protoplasts of the epidermis, cortex, endodermis, and root pericycle.
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2. It is a faster process of water movement and water moves through mass flow.
| 2. It is a slower process of water movement.
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(f) Guttation and Transpiration
Guttation
| Transpiration |
1. It occurs usually at night.
| 1. It occurs usually during the day.
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2. Water is lost from the leaves in the form of liquid droplets.
| 2. Water is lost from the leaves in the form of water vapour.
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3. It occurs through the vein endings of leaves.
| 3. It occurs through the stomata.
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4. It is an uncontrolled process.
| 4. It is a controlled process. |