Respiratory Systems In Plants And Mechanism

Hi, welcome again to this hall on the topic, the respiratory systems in plants.

Table Of Contents

1. Respiratory systems in plants.
2. Mechanism of gaseous exchange in plants.
3. Differences between respiration and photosynthesis.
4. Revision Questions.

Respiratory Systems In Plants

Plants do not have special respiratory organs for gaseous exchange. However gases moved in and out of the plants through the stomata and lenticels.

Read Also

• Types of respiration, meaning and importance
• Excretion in mammals
• Meaning of cell, history and theory
• Characteristics of living and non living things, meaning and examples
• Reproductive systems in mammals and their functions

STOMATA

Description: Stomata (singular: stoma) are very thin openings found in the epidermis of leaves and stems of seedlings. Each stoma is surrounded by two bean-shaped cells called guard cells. Stomata are more abundant in the lower epidermis of leaves and are very few in the upper epidermis.

LENTICELS

Description: Lenticels are breathing pores or tiny openings found in the bark of older stems. A lenticel consists of a loose mass of small thing-walled cells which permit easy diffusion of gases in and out of the plant.

Mechanism Of Gaseous Exchange In Plants

The shoot system of flowering plants obtains oxygen from the atmosphere and gives out carbon dioxide and water vapour to the atmosphere through the stomata of leaves and lentices in the stem through the process of diffusion. Due to differences in concentration gradient, oxygen is taking in through the stomata and lenticels especially during the night and carbon dioxide and water vapour are giving out.

But during the day, when photosynthesis is going on, oxygen and water vapour from photosynthesis diffuse out to the exterior through the stomata and lenticels. It will be recalled that the closing and opening of the stomata are controlled by the guard cells. Turgidity of the guard cells quicken the opening of the stomata while flaccidity of the guard cells causes the closing of the guard cells. Gaseous exchange, especially through the stomata, is made possible when the stomata open.

Differences Between Respiration And Photosynthesis

Respiration

1. Respiration occurs in every living cells
2. Respiration takes place at all time
3. Food substances are broken down (i.e catabolism).
4. High energy containing food (i.e. oxygen and carbohydrate are used).
5. Carbon dioxide and water are the by-products
6. Respiration releases energy –
7. Respiration results in a decrease in weight

Photosynthesis

1. Photosynthesis occurs only in autotrophs.
2. While photosynthesis will only take place in the presence of sunlight.
3. Food substances are built up (i.e anabolism).
4. Low energy substances like carbon dioxide and water are used.
5. Oxygen is the by-product.
6. Photosynthesis makes use of energy.
7. Photosynthesis results in an increase in weight.

Revision Questions

1. Briefly describe the mechanism of gaseous exchange in plants.
2. Name the respiratory systems in plants.
3. Outline five differences between respiration and photosynthesis