Biology
Plants have 2 transport systems:
Plants can be very large, but they have a branching shape which helps to keep the surface area to volume ratio fairly large. Their energy needs are generally small compared with those of animals, so respiration does not take place so quickly.
They can therefore rely on diffusion to supply their cells with O2 and to remove CO2. Their leaves are very thin and have a large surface area inside them in contact with the air spaces. This means that diffusion is sufficient to supply the mesophyll cells with CO2 for photosynthesis, and to remove O2. Plant transport systems therefore do not transport gases.
Transverse section of roots, stems and leaves of herbaceous dicotyledonous plants
1. Root
2. Stem
Xylem tissue
Xylem tissue contains dead, empty cells with no end walls. These are called xylem vessel elements. They are arranged in long lines to form xylem vessels. These are long, hollow tubes through which water moves by mass flow from the roots to all other parts of the plant.
- Phloem & Xylem
Are Phloem and Xylem Similar? What are the Differences? Similarities: Phloem and xylem are tissues in a plant that transport food and water. Both are vascular tissues and when they work together to effectively transport food, water and minerals they form...
- #42 Summary Of Transport In Multicellular Plants
1. Multicellular organisms with small surface area to volume ratios need transport systems. 2. Water and mineral salts are transported through a plant in xylem vessels. Movement of water is a passive process in which the water moves down a water...
- #41 Transport In Phloem
The movement of substances in phloem tissue is called translocation. The main substances that are moved are sucrose and amino acids, which are in solution in water. These substances have been made by the plant and are called assimilates. Phloem...
- #40 Movement Of Water And Minerals In The Xylem
Most plants secure the water and minerals they need from their roots. The path taken is: soil -> roots -> stems -> leaves. The minerals (e.g., K+, Ca2+) travel dissolved in the water. Water and minerals enter the root by separate paths which...
- #38.1 Transport In Multicellular Plants - Syllabus 2015
? The need for, and functioning of, a transport system in multicellular plants Learning Outcomes Candidates should be able to: (a) explain the need for transport systems in multicellular plants and animals in terms of size and surface area to...
Biology
#39 Structure of transport tissues in plants
- xylem: transports water and inorganic ions from the roots to the leaves.
- phloem: transports food made in the plant (sucrose and amino acids) from the leaves to the rest of the plant.
Plants can be very large, but they have a branching shape which helps to keep the surface area to volume ratio fairly large. Their energy needs are generally small compared with those of animals, so respiration does not take place so quickly.
They can therefore rely on diffusion to supply their cells with O2 and to remove CO2. Their leaves are very thin and have a large surface area inside them in contact with the air spaces. This means that diffusion is sufficient to supply the mesophyll cells with CO2 for photosynthesis, and to remove O2. Plant transport systems therefore do not transport gases.
1. Root
3. Leaf
Xylem tissue
Xylem tissue contains dead, empty cells with no end walls. These are called xylem vessel elements. They are arranged in long lines to form xylem vessels. These are long, hollow tubes through which water moves by mass flow from the roots to all other parts of the plant.
 |
| Xylem tissue. |
| Syllabus 2015 (d) [PA] describe the distribution of xylem and phloem tissue in roots, stems and leaves of dicotyledonous plants; (e) [PA] describe the structure of xylem vessel elements, phloem sieve tube elements and companion cells and be able to recognise these using the light microscope; (f) relate the structure of xylem vessel elements, phloem sieve tube elements and companion cells to their functions; |
Syllabus 2016 7.1 Structure of transport tissues Plants have two transport tissues: xylem and phloem. a) draw and label from prepared slides plan diagrams of transverse sections of stems, roots and leaves of herbaceous dicotyledonous plants using an eyepiece graticule to show tissues in correct proportions (see 1.1c) b) draw and label from prepared slides the cells in the different tissues in roots, stems and leaves of herbaceous dicotyledonous plants using transverse and longitudinal sections c) draw and label from prepared slides the structure of xylem vessel elements, phloem sieve tube elements and companion cells and be able to recognise these using the light microscope d) relate the structure of xylem vessel elements, phloem sieve tube elements and companion cells to their functions |
- Phloem & Xylem
Are Phloem and Xylem Similar? What are the Differences? Similarities: Phloem and xylem are tissues in a plant that transport food and water. Both are vascular tissues and when they work together to effectively transport food, water and minerals they form...
- #42 Summary Of Transport In Multicellular Plants
1. Multicellular organisms with small surface area to volume ratios need transport systems. 2. Water and mineral salts are transported through a plant in xylem vessels. Movement of water is a passive process in which the water moves down a water...
- #41 Transport In Phloem
The movement of substances in phloem tissue is called translocation. The main substances that are moved are sucrose and amino acids, which are in solution in water. These substances have been made by the plant and are called assimilates. Phloem...
- #40 Movement Of Water And Minerals In The Xylem
Most plants secure the water and minerals they need from their roots. The path taken is: soil -> roots -> stems -> leaves. The minerals (e.g., K+, Ca2+) travel dissolved in the water. Water and minerals enter the root by separate paths which...
- #38.1 Transport In Multicellular Plants - Syllabus 2015
? The need for, and functioning of, a transport system in multicellular plants Learning Outcomes Candidates should be able to: (a) explain the need for transport systems in multicellular plants and animals in terms of size and surface area to...