Definition and principle of biological transpiration

Transpiration is the process by which water is lost into the atmosphere in a state of water vapor from the surface of a living plant body (mainly leaves). Unlike the process of evaporation in physics, transpiration is not only affected by external environmental conditions, but also regulated and controlled by the plant itself, so it is a complex physiological process. When plants are young, all surfaces exposed to air can transpire.

The transpiration of growing plants is mainly in the leaves. There are two ways of leaf transpiration: one is transpiration through the stratum corneum, which is called cuticle transpiration; The second is transpiration through stomatal transpiration, which is called stomatal transpiration, and stomatal transpiration is the most important way of plant transpiration.

Physiological significance of transpiration: it is the main driving force for plants to absorb and transport water, which can accelerate the rate of transport of inorganic salts to the aboveground parts, reduce the temperature of the plant body, and enable the leaves to photosynthesize under strong light without being damaged. The amount of water lost by plant transpiration is significant.

It is estimated that it takes one corn plant to be consumed from seedling emergence to harvest.

Four or five hundred pounds of water. Autotrophic green plants must exchange gases with their surroundings during photosynthesis. Therefore, the water in the plant is inevitably lost along the water potential gradient, which is the inevitable result of the plant's adaptation to life on land.

Proper inhibition of transpiration not only reduces water consumption, but is also beneficial to plant growth. Under high humidity conditions, the plant grows more luxuriantly. In the production of vegetables and other crops, the use of sprinkler irrigation can increase air humidity and reduce transpiration, which can generally increase yield compared with soil irrigation.

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Ay. Root hairs - ducts - leaf veins - white.

The concept of transpiration is the process of water being lost from the surface of the living plant body (mainly leaves) to the atmosphere in a state of water vapor, which is different from the evaporation process in physics, transpiration is not only affected by external environmental conditions, but also regulated and controlled by the plant itself, so it is a complex physiological process.

The main processes are, moisture in the soil, root hairs, intra-root ducts, intrastem ducts, intra-leaf ducts, stomata, and atmosphere. When plants are young, all surfaces exposed to air can transpire.

Stomatal transpiration:

Transpiration through stomata is called stomatal transpiration, and stomatal transpiration is the most important way of plant transpiration. Stomata are important gateways for in and out of the body of plants. Water vapor (H2O), carbon dioxide (CO), and oxygen (O2) all share the stomata channel, and the opening and closing of the stomata will affect the physiological processes of plants such as transpiration, photosynthesis, and respiration.

Stomata are small pores in the epidermal tissue of plant leaves, which are generally composed of pairs of guard cells. Guard cells are surrounded by epidermal cells, and adjacent epidermal cells that are morphologically identical to other epidermal cells are called adjacent cells, and if they are distinctly different, they are called paraguard cells.

Transpiration refers to the process by which water in a plant is lost into the atmosphere in the form of a gas through a stomata in the form of a gas.

Transpiration is not only affected by external environmental conditions, but also regulated and controlled by the plant itself, so it is a complex physiological process. When plants are young, all surfaces exposed to air can transpire.

The speed of transpiration is determined by the vapor pressure difference between the inside and outside of the leaf, so all external conditions that affect the vapor pressure difference between the inside and outside of the leaf will affect transpiration.

Significance of plant transpiration

1. Transpiration is the driving force for roots to absorb water, prompting roots to absorb water from the soil, promoting water circulation, evaporating water from the soil into the atmosphere, and returning to the ground as rain.

2. It promotes the transportation of water and inorganic salts, so that the inorganic substances absorbed by the roots are transported to all parts of the plant. The upward force of transpiration makes the plant resist gravity and elongate upward.

3. Transpiration can also reduce the temperature of the surface of the plant body, and transpiration can also increase atmospheric humidity, increase precipitation, reduce atmospheric temperature, and regulate climate. Transpiration fills the inside of the plant with water, providing water to animals that do not drink alone.

Transpiration refers to the process by which water diffuses through the surface of plants into the atmosphere in a gaseous state. According to the different diffusion pathways, it can be divided into stomatal transpiration, stratum corneum transpiration and cutaneous transpiration, among which stomatal transpiration can account for 80% to 90% of the total transpiration when the stomata are open. However, the opening degree of the stomata varies with the internal and external environment of the plant, for example, at night, at noon in summer, and in hot and drought, the stomata are closed, the resistance increases, and the transpiration rate is very low.

Due to the loss of a large amount of water due to transpiration, plants are susceptible to water stress, which is considered an inevitable disaster for terrestrial plants.

1. Promote the transportation of water and inorganic salts in plants;

2. Promote the absorption of mineral ions by the roots;

3. Reduce the temperature of the surface of plant leaves;

4. Provide a large amount of water vapor for the atmosphere, keep the local air moist, reduce the temperature, and let the local rain be abundant, forming a virtuous cycle.

On the one hand, it can pull the transport of water and inorganic salts in the body to ensure the needs of various tissues for water and inorganic salts, and on the other hand, through transpiration in the hot summer, we can reduce the temperature of the leaf surface and avoid plants being burned due to high temperatures.

1. It can reduce the temperature of the plant so that the plant will not be burned.

2 is the main driving force for roots to absorb water and promote the transport of water in the body3 can promote the transport of inorganic salts dissolved in water in the body.

4. It can increase atmospheric humidity, reduce ambient temperature and increase precipitation. Promote the biosphere water cycle88

Transpiration: The process by which water in terrestrial plants is emitted (evaporated) to the atmosphere in a vapor state. It proceeds through the epidermis of the aboveground part of the plant, mainly through the stomata on it. The guard cells that make up the stomata move in response to changes in the internal and external conditions of the plant, causing the stomata to open and close, thereby causing a change in the resistance of water vapor diffusion.

Transpiration is therefore essentially a physical process (evaporation) under physiological regulation (stomatal movement).

Evaporative evapotranspirationThe process by which water evaporates through the surface of a living plant is called transpiration. Significance of evaporative transpiration: the significance of evaporative transpiration, promoting the absorption of water by roots, promoting the transportation of water and inorganic salts, in addition, transpiration is the power of root water absorption, prompting roots to absorb water from the soil, promoting water circulation, and the process of evaporation of water through the surface of living plants is called transpiration.

Significance of evapotranspiration: The significance of evaporative transpiration promotes the absorption of water by roots, promotes the transportation of water and inorganic salts, and transpiration is the driving force for root water absorption, which promotes the absorption of water by roots from the soil and promotes water circulation