In this IBDP Biology post, we will look into the structure of phloem, and the differences between phloem and xylem, let's get to it!
The Structures and their Functions of Phloem
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/916529_688349.jpeg)
Phloem is made of living cells
Sieve elements: Elongated living cells that form from the phloem tissue
1. Phloem sieve tube: Develop from sieve tube elements (coloumns of cells) that break down nuclei and organelles. It has lumen for easy flow of sap
Sieve tube: Several sieve elements that are connected end to end
Sieve plate: Cross walls within the sieve tubes that are perforated (pores)
2. Sieve plate: Cross wall that strengthens the sieve tube, the plate has pores which allows sap to flow through
3. Cell membrane: Inside of wall that holds sap inside the sieve tubes and has pumps to load and unload sucrose
4. Cell wall: Resists high pressure within the sieve tubes
Phloem and Transport
Translocation: The process of transporting organic compounds (sugars and amino acids) made during photosynthesis in the phloem sieve tubes
Plant cells need organic compounds to function
- Many organic compounds are made in the chloroplasts
- The phloem transports the organic compounds around the plant
Comparing Xylem and Phloem
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/180315_59181.png)
Phloem
- Coloumns of living cells
- Transports sugars, amino acids and plant hormones
- Companion cells carry out cell functions with many mitochondria that provide ATP for Active Transport
- Sieve tubes have sieve plates that controls the flow of sap
Xylem
- Coloumns of dead cells
- Transports water and minerals
- Thickened cell wall consisting of lignin
- Continuous tube which allows for an unbreakable coloumn of water
That's all for this post!
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/294038_376873.png)
References:
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.vedantu.com%2Fquestion-answer%2Fdraw-and-label-the-diagram-of-phloem-class-11-biology-cbse-5f59a9536e663a29cca585f3&psig=AOvVaw3Gix0MVnCoyz6loK_g7fEm&ust=1626977048896000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCPiAzvrf9PECFQAAAAAdAAAAABAD
- https://www.google.com/url?sa=i&url=http%3A%2F%2Fib.bioninja.com.au%2Fhigher-level%2Ftopic-9-plant-biology%2Funtitled%2Fxylem-versus-phloem.html&psig=AOvVaw3N8Jqn8mlgmAcg4ViP9EEd&ust=1626976973547000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCMCMpeXg9PECFQAAAAAdAAAAABAD
Drafted by Venetia (Biology)