How do trees absorb water? How trees absorb water

By osmotic action.

Water flows from a place with a low concentration to a place with a high concentration, and the concentration of liquid in the root tissues of the plant is higher than the concentration of the surrounding water environment, so that the surrounding water flows to the root tissues, and there is also the transpiration produced by the leaves of the plants.

The leaves of the plant will need water from the branches and roots to recuperate, just like a water pump, and this transpiration will accelerate the water absorption by the roots. This is also a good explanation for why saline land.

The reason why plants die easily. Because the concentration of liquid in the roots is always lower than the concentration of the surrounding environment, the moisture in the roots flows to the land.

It is mainly the effect of osmotic pressure, the concentration of fluid inside and outside the plant cells is different, there is osmotic pressure, and osmotic pressure makes the water rise to a height of several meters.

Through the roots of trees, trees in general have a very developed root system. Trees obtain water and other needed nutrients from the soil through them. It is transmitted through the trunk to the branches and leaves of the tree, so that it can cooperate with normal photosynthesis, so as to grow and develop!

Water is absorbed through the roots and transported to the individual branches and leaves through the bark.

After the cabbage leaves are placed vertically into different pigment solutions, the color spots of the corresponding pigments gradually appear in the cabbage leaves over time, and after standing for 24 hours, the color of the cabbage leaves becomes pigment color. It turns out that the roots and leaves of the plant contain tiny ducts. Under the pull of transpiration, plants transport water from the soil to the rhizomes and leaves through these ducts.

When there is a concentration difference between the inside and outside of the plant cell, the plant cell will absorb or lose water The concentration of the solution outside the cell is greater than the concentration inside the cell, and the cell absorbs water when the concentration of the solution outside the cell is less than the concentration inside the cell By comparing the cell A cell swells, indicating that the water flows into the cell, indicating that the plant cell absorbs water Figure B cell shrinks, indicating that the concentration outside the cell is large, indicating that the plant cell loses water

1) For large trees that have been dry and rainy for a long time, the leaves that were originally low-hanging and wilting will gradually stretch and stiffen, and they will be verdant At this time, the state of the plant cell is Tu A, and the water flows into the cell, indicating that the plant cell absorbs water; Plant cells swell as they absorb water, and wilted leaves gradually stretch and stiffen

2) When using salt and cucumber to make cold dishes, a large amount of salty soup will gradually ooze out The state of cucumber cells at this time is Figure B, and the water flows to the outside of the cell, indicating that the concentration outside the cell is large, and the plant cells lose water Therefore, after a period of time, a large amount of salty soup will appear on the plate

3) The principle of water absorption and water loss in plant cells is: when the concentration of the external solution of the cell is greater than the concentration of the cell fluid, the cell loses water, and when the concentration of the external solution of the cell is less than the concentration of the cell fluid, the cell absorbs water

Therefore, the answer is: (1) A;

2) B;(3) Less than

The inside of silica gel is a nanoscale microporous structure, and there are a large number of hydroxyl groups on its surface. Through the mutual attraction between molecules, the hydroxyl group affinities with the water molecules in the air, thus achieving water absorption.

Silica gel alias: silicate gel, is a highly active adsorption material, is an amorphous substance. The main component of silica gel is silica, which is chemically stable and does not burn.

Silica gel has an open porous structure, strong adsorption, and can adsorb a variety of substances. Dilute sulfuric acid (or hydrochloric acid) is added to the aqueous solution of water glass and allowed to stand, it becomes a hydrous silicate gel and solids.

In detail, there are three points: the first is root pressure. In general, the concentration of cell sap in plant roots tends to be greater than that in soil solutions.

Therefore, water always penetrates into the roots, creating a kind of pressure, which is called root pressure. If the trunk is cut off, sap flows out of the section, which is called wound fluid, and this phenomenon is caused by root pressure. Root pressure causes the moisture from the roots to rise to the above-ground parts.

The root pressure of some herbaceous plants is less than 1 atmosphere, while the root pressure of trees is much more, and the root pressure of a large tree with a height of 10 meters can reach 2 3 atmospheres. Another force for the rise of moisture is the transpiration pull. During leaf transpiration, the mesophyll cells near the substomatal cavity lose water and need to obtain water from the adjacent cells.

At the same time, the next cell gets water from another cell, and so on, it asks for water from the duct. Finally, the roots absorb water from the environment to replenish it. The water absorption force generated by the transpiration process is called transpiration pull, which is greater than the root pressure and is the main driving force for the rise of water, which can quickly transport the water absorbed by the roots to all parts of the plant.

The third is cohesion. In the process of water transport to the leaves, there is a special attraction between the water molecules in the roots, stems, and leaf vein ducts - cohesion, which is able to maintain the water in the plant and form a continuous one"Water column"。The water molecules are very firmly bound to each other, ensuring that the water in the catheter forms a continuous water column and the water continues to rise.

Due to the action of root pressure, transpiration pull, and cohesion, groundwater is quickly transported to the canopy. Its speed can rise by 45 meters per hour, and the slowest can rise by 5 meters per hour. In about 15 minutes, a wheat plant can be covered with groundwater.

The water of plant leaves is evaporated under the sun, and the concentration of cell sap in the leaves becomes larger after evaporation, and osmotic action occurs to absorb water downward, and then downwards in turn, this process is called transpiration water absorption.

Plant transpiration provides a pulling force for the roots to absorb water. The taller the tree, the more lush the foliage, the stronger the transpiration and the greater the pulling force provided.

The catheter inside the woody layer is transported.

1. Improve the water absorption capacity of plants.

1. For small seedlings, use nutrient bowls to raise seedlings and transplant them with soil, so as not to damage the root system and improve the survival rate.

2. If you plant seedlings in the ground, do not dig up the main root system when digging seedlings, try to retain as many roots as possible and protect the root system.

3. For transplanting large trees, you need to transplant with soil balls.

After transplanting, watering in time and covering the mulch film can play a role in water retention.

In the case of large trees, special infusion bags can be used to infuse nutrient solution into large trees to improve the water absorption capacity of plants.

2. Reduce the ability of plants to lose water.

1. Remove most of the leaves, and only keep a few leaves to reduce transpiration.

2. Remove unnecessary branches, retain the main trunk and main branches, and reduce transpiration.

3. Spray a regulator that inhibits transpiration.

Choose a cloudy day transplant, reduce the leaves of the plant body, and water it after transplanting.

The roots of large trees can not only absorb water, but also transport nutrients through the roots to the trunk branches and leaves.