Describe the transportation system in plants.
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[Textbook Question 7d pg no.178]
The transportation in plants consists of two main elements of conductive tissues: xylem and phloem
The roots absorb water and minerals from the soil which is transported from the base of the stem to the leave-apex via xylem. Phloem transports food materials from leaves to the other parts.
The following can be explained as follows:
- Water and minerals transportation :
In the first step, water and minerals are observed by the roots of the plant. The water and minerals absorbed by the roots are moved into the vascular tissues (xylem specifically) to be transported to various parts of plant-body.
The two forces- root pressure and transpiration pull respectively are responsible for this upward (against the force of gravity) movement.
1.Root pressure: this is the positive pressure due to which water (along with mineral ions) enters into the vascular tissues following the concentration gradient (i.e., from higher concentration to lower concentration). But the major part of water transportation occurs via transpiration pull.
2.Transpiration pull: it is basically the 'pull' of water from leaves. T transpiration process creates a tension which pulls the water up. To compensate for the water loss (via transpiration process), water is pulled up by the leaves.
- Food transportation :
- The process of transportation of food from leaves to various parts of the plant occurs by phloem (an integrated part of vascular tissue). This phenomenon of food transportation is defined as translocation.
Translocation: This is the process through which the phloem transport the food material (like glucose, amino acids etc) to the developing regions and storage organs (e.g., roots, fruits and seeds etc) as well.
The phloem consists of following parts:
- Sieve tubes
- Companion cells
- Phloem fibres and;
- Phloem parenchyma
Translocation in the phloem, unlike xylem, occurs via utilising a molecule of ATP(which releases energy). e.g., food molecule like sucrose is transported into the phloem by utilising molecule of ATP.
The transportation in plants consists of two main elements of conductive tissues: xylem and phloem
The roots absorb water and minerals from the soil which is transported from the base of the stem to the leave-apex via xylem. Phloem transports food materials from leaves to the other parts.
The following can be explained as follows:
- Water and minerals transportation :
In the first step, water and minerals are observed by the roots of the plant. The water and minerals absorbed by the roots are moved into the vascular tissues (xylem specifically) to be transported to various parts of plant-body.
The two forces- root pressure and transpiration pull respectively are responsible for this upward (against the force of gravity) movement.
1.Root pressure: this is the positive pressure due to which water (along with mineral ions) enters into the vascular tissues following the concentration gradient (i.e., from higher concentration to lower concentration). But the major part of water transportation occurs via transpiration pull.
2.Transpiration pull: it is basically the 'pull' of water from leaves. T transpiration process creates a tension which pulls the water up. To compensate for the water loss (via transpiration process), water is pulled up by the leaves.
- Food transportation :
- The process of transportation of food from leaves to various parts of the plant occurs by phloem (an integrated part of vascular tissue). This phenomenon of food transportation is defined as translocation.
Translocation: This is the process through which the phloem transport the food material (like glucose, amino acids etc) to the developing regions and storage organs (e.g., roots, fruits and seeds etc) as well.
The phloem consists of following parts:
- Sieve tubes
- Companion cells
- Phloem fibres and;
- Phloem parenchyma
Translocation in the phloem, unlike xylem, occurs via utilising a molecule of ATP(which releases energy). e.g., food molecule like sucrose is transported into the phloem by utilising molecule of ATP.
