Transport of substance in plants
To circulate water, essential nutrients, excretory products, and gases within the plants for various purposes, transportation in plants is necessary. In vascular tissues, this transportation in the plant takes place. By a suction force, water and minerals are transported to various parts of the plant.
TRANSPORTATION IN PLANTS - CBSE (CHAPTER-9)NBIOLOGY
1.
2. The transport system in plants consists of bundles of tubes in the
stem, branches and roots. These tubes are called xylem and phloem.
The main function of xylem is to transport water and dissolved
minerals from the roots to rest of the plant body.
3. To circulate water, essential nutrients, excretory products, and gases
within the plants for various purposes, transportation in plants is
necessary. In vascular tissues, this transportation in the plant takes
place. By a suction force, water and minerals are transported to
various parts of the plant.
4. Plants absorb water and minerals by the roots. The roots have root
hair. The root hair increase the surface area of the root for the
absorption of water and mineral nutrients dissolved in water. The
root hair is in contact with the water present between the soil
particles.
5. Can you guess how water moves from the root to the leaves? What
kind of transport system is present in plants? Plants have pipe-like
vessels to transport water and nutrients from the soil. The vessels are
made of special cells, forming the vascular tissue. A tissue is a group
of cells that perform specialized function in an organism. The
vascular tissue for the transport of water and nutrients in the plant
is called the xylem.
6. Vascular tissues are normally conducting tissues. The formation of
these tissues can be done by xylem and phloem of a plant. Without
the use of pump how water moves up the plant against gravity in
tubes made of dead xylem cells can be explained by only the
transportation process.
7. Transport of water and minerals
In plants, there are pipe-like vessels through which water and
minerals can enter the plants. These vessels are made up of
elongated cells and thick walls. A group of cells forms a tissue that
performs a specialized function within the organisms. These
are conducting tissues. These conducting tissues are divided into two
types which are xylem and phloem.
8. •Xylem: It is a vascular tissue that spreads from the top to bottom of
the plant. For the transport of water molecules, it helps a lot. It also
plays a vital role in the case of dissolved substances from the root
hairs to aerial parts of the plant. It transfers water in one
direction. Commonly, xylem occupies the central part of the vascular
bundle.
9. •Phloem: It is also vascular tissue. In a plant where the necessity of
food molecules is there, the use of the phloem transportation process
will take place.
10. The food manufactured in the leaves is transported to different parts
of the plant. This transpiration of food material from leaves to the
others parts of plant is carried out by the tissue called phloem and
process transport food material is called translocation. The phloem
consists of those vessels known as sieve tubes. Xylem and phloem
together form the vascular or connective tissue.
11. Transpiration:
Transpiration is a process that involves loss of water vapour through
the stomata of plants. Transpiration is thought to be a 'necessary
cost or evil' to allow the plant to absorb water from the soil. It is an
inevitable process.
12. Transpiration is important in plants for three major reasons:
Cooling of the plant: the loss of water vapour from the plant cools
down the plant when the weather is very hot.
13. The transpiration pull: when the plant loses water through
transpiration from the leaves, water and mineral salts from the stem
and roots moves, or is `pulled', upwards into the leaves. Water and is
therefore taken up from the soil by osmosis and finally exits the
plants through the stomata.
14. Plant structure: young plants or plants without woody stems require
water for structural support. Transpiration helps maintain the
turgidity in plants.