Transportation in Plants and Animals: Processes, Types, and Importance

Transportation in plants and animals is essential for carrying water, minerals, nutrients, and other vital substances to every cell in an organism. This process ensures proper growth, development, and maintenance of life. In plants, transportation largely focuses on the movement of water and nutrients, whereas transportation in animals often involves the circulatory system distributing blood, oxygen, and other substances.

What is The Meaning of Transportation in Animals and Plants?

Transportation in plants and animals refers to the organised movement of essential substances—such as water, nutrients, gases, and waste products—within their bodies. In simpler terms, it is how each cell receives what it needs to function and also disposes of what it does not.

• In plants, transportation ensures that water and minerals absorbed by the roots reach the stems and leaves. It also delivers the sugars produced in the leaves (during photosynthesis) to all other parts of the plant.

• In animals, transportation includes the circulation of blood, which carries oxygen from the lungs to the cells and carbon dioxide back to the lungs for expulsion. It also transports nutrients from the digestive system to cells across the body.

What are The Types of Transport in Animals and Plants?

Whether we are discussing transportation in plants and animals, there are common types of transport at the cellular and tissue level:

1. Simple Diffusion

• Movement of molecules from a region of higher concentration to a region of lower concentration.

• Does not require energy (passive).

• Important for the exchange of gases like carbon dioxide and oxygen.

2. Facilitated Diffusion

• Involves carrier proteins or channel proteins to help substances move across membranes passively.

• Useful for molecules that cannot directly diffuse through the lipid bilayer.

3. Osmosis

• A special type of diffusion involves water molecules moving across a semi-permeable membrane.

• Moves from a region of higher water potential to one of lower water potential.

4. Active Transport

• Moves substances against their concentration gradient (from lower concentration to higher concentration).

• Requires energy in the form of ATP.

In addition to these, plants have specialised vascular tissues (xylem and phloem), and animals typically have a circulatory system (open or closed).

Transportation in Plants

When we specifically talk about plants, transportation in plants focuses on moving water, minerals, and synthesised nutrients throughout their structure. Let us delve deeper:

Vascular Tissues in Plants

1. Xylem

• Primarily transports water and dissolved minerals from the roots to the aerial parts of the plant.

• Consists of non-living conducting cells such as tracheids and vessels. (For more information, see Difference between Tracheids and Vessels.)

• Water movement in the xylem is heavily influenced by transpiration pull and cohesion-tension forces.

2. Phloem

• Transports food (mainly sugars, like sucrose) synthesised in the leaves to other parts of the plant.

• Composed of living cells such as sieve tubes and companion cells. (For more details, refer to Differences between xylem and phloem.)

• The process is called translocation and requires energy (active transport) to create pressure gradients.

Mechanisms of Water Absorption

1. Active Absorption

• Occurs when root cells actively take up ions from the soil, creating a gradient for water to move into the roots.

• Slow process and influenced by temperature, humidity, and metabolic activities of root cells.

• It can be halted by metabolic inhibitors.

2. Passive Absorption

• Driven largely by the transpiration pull created in leaves.

• Rapid process in plants with high transpiration rates.

• Water moves via cell walls (apoplast pathway) and eventually reaches xylem vessels.

Translocation of Food

• Transport of sugars and other nutrients from leaves to growing and storage regions via the phloem.

• Requires energy (in the form of ATP) to generate osmotic pressure differences that drive movement.

Transpiration in Animals and Plants

What is Transpiration in animals and plants?
Transpiration is typically a plant-specific term and does not precisely occur in animals the same way. In plants, transpiration is the loss of water in the form of vapour, primarily through small openings called stomata on the leaves.

• Transpiration in Plants

• Helps cool the plant and maintains the continuous upward movement of water (transpiration pull) in the xylem.

• Ensures mineral transport and maintains plant turgidity.

• Influenced by temperature, humidity, wind, and light.

• Transpiration in Animals?

• Animals do not transpire in the same manner. Instead, they have different means to remove excess water or heat (like sweating in humans, panting in dogs, or evaporative cooling in some other species).

• While the term “transpiration” generally applies to plants, understanding this distinction clarifies that animals have parallel processes to balance heat and water content rather than ‘transpiration’ per se.

Transportation in Animals

Transportation in animals involves a circulatory system that distributes blood, nutrients, oxygen, and hormones to every cell. It also carries waste products to excretory organs. Depending on the species, this circulatory system can be:

1. Open Circulatory System

• Common in insects and some molluscs.

• Blood (or haemolymph) flows freely within the body cavity, bathing organs directly.

• Less efficient at oxygen and nutrient transport over long distances.

2. Closed Circulatory System

• Found in vertebrates such as fish, amphibians, reptiles, birds, and mammals.

• Blood circulates within a network of vessels (arteries, veins, and capillaries).

• More efficient delivery of oxygen and nutrients and better regulation of blood pressure.

In humans and many other animals, the main components of the circulatory system include:

• Heart: Pumps blood throughout the body.

• Blood Vessels: Arteries carry blood away from the heart, veins carry blood toward the heart, and capillaries facilitate exchange with tissues.

• Blood: Contains red blood cells (for oxygen transport), white blood cells (for immunity), platelets (for clotting), and plasma (the fluid medium).

Quick Quiz

1. Which tissue transports sugars in plants?

2. Name two factors affecting the rate of transpiration.

3. What is the basic difference between open and closed circulatory systems in animals?

4. How does active transport differ from facilitated diffusion?

5. Which cells in the blood are responsible for defence against infection?

Answers -

1. The phloem is responsible for transporting sugars (like sucrose) and other organic nutrients from leaves to different parts of the plant.

2. Temperature: Higher temperatures generally increase transpiration by causing water to evaporate more quickly from leaf surfaces.

Humidity: Lower humidity levels lead to a steeper water potential gradient between leaf and air, thereby increasing transpiration.

(Other factors include wind speed, light intensity, and the number of open stomata.)

3. Open Circulatory System: Blood (haemolymph) is not always contained within blood vessels and directly bathes the organs in the body cavity.

Closed Circulatory System: Blood flows entirely within a network of vessels (arteries, veins, and capillaries), ensuring a more efficient and controlled distribution of nutrients and oxygen.

4. Active Transport: Requires energy (ATP) to move substances against their concentration gradient (from lower to higher concentration).

Facilitated Diffusion: Moves substances down their concentration gradient (from higher to lower concentration) through specific carrier or channel proteins without using cellular energy.

5. White Blood Cells (Leukocytes) protect the body by fighting pathogens, foreign substances, and infections.

For further insight on key differences, explore our articles on -  

• Difference between Active and Passive Transport

• Facilitated Diffusion