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 Biology: Transport in plants🌲 (0610)

So, I am officially starting the IGCSE notes and preparation series to make it easier for you to understand the concepts.

Beginning with transport in plants.

It is a very intriguing topic, so do take a look at it.

I will paste some topic related questions for you to solve and you can comment the answers below.

I will disclose the answers at the very end of the next blog. 😊

All the Images shared in the blog are owned by me and so unauthorized use would not be tolerated.

Transport in plants.

Xylem and Phloem:

Xylem:

• Hollow and has no nucleoplasm and no end walls
• It even has pits that prevent air bubbles.
• It is made up of dead cells.
• Lignin deposited on the cell wall for strength of the plants 

Function:

• To transport mineral ions and water.
• Helps to support the petiole.

Diagram above is a pictorial representation of the mineral ions

Phloem:

• Is made up of sieve tube elements, and the sieve tube plates are porous.
• They have a companion cell that directs the sucrose and amino acids from source to sink.

Function:

• Translocation of sucrose and amino acids from source to sink.

 

Simplistic diagram of phloem

Water uptake:

Root hair cells:

• They have a large surface area and mitochondria for aerobic respiration to provide energy to protein carriers in the root hair cells to absorb the ions.
• Active Transport takes place to let the molecules in.
• So basically, the ions move from the lower to higher concentration against the concentration gradient through the protein carriers into the root hair cells due to the energy from aerobic respiration in the mitochondria. (I would make another blog about this topic)
• Water and mineral ions move in the xylem vessels in one direction only!!!!

• Forces of cohesion and adhesion act amongst the water molecules and act amongst the water molecules with the xylem vessels

• Adhesion: Adhesion is the term used to describe the attraction between water molecules and the walls of xylem vessels.

• Cohesion: Attraction between water molecules due to strong hydrogen bonding

Transpiration:

• Loss of water from the area parts of the plant through diffusion from the stomata
•  Water evaporates from the mesophyll layer of cells and out through the stomata.

Transpiration Pull: is a biological process that generates a pulling force within the xylem tissue of plants, facilitating the upward movement of water into the xylem vessels. That is because water is lost from the area parts of the plants, for example like the: spongy mesophyll cells.

 Factors that affect the rate of transpiration:

Wind:

 The more the wind, the more the rate of transpiration concentration gradient for diffusion would increase.

Humidity: 

The more the humidity, the less the rate of transpiration because there would be little to no gradient for the water vapors to diffuse out of. 

Temperature: 

The higher the temperature, the more the rate of transpiration increases in kinetic energy of particles. However, at extremely high temperatures the stomata close to help the plant to survive in high temperatures to limit wilting and preventing transpiration.

 

Wilting:

This is due to high temperature and low water absorption rate, due to which the cells lose their turgidity through osmosis and become dehydrated, this causes them to become plasmolyzed.

Plasmolysis is the process where plant cells lose water in a hypertonic solution, which has a higher solute concentration than the cell's interior. Osmosis drives water from the cells into the solution, causing the protoplasm to contract from the cell wall. This can result in cell death if water loss is extensive. Plant cells are protected from bursting by their rigid cell walls, unlike animal cells.

 

Sources and sinks:

1. Sources in plants are structures that produce or release sugars necessary for growth. For example, leaves produce sugars via photosynthesis, while storage organs like bulbs and tubers accumulate surplus sugars for later use. Conversely, sinks are parts of the plant, such as roots, new shoots, and developing fruits, that depend on these sugars for their development, as they cannot produce enough on their own.

 Some parts of the plants may act like sources and sinks interchangeably throughout the year. For example, in summer, leaves may provide a source of food, but in winter, parts of the plants like stems and roots do provide most of the sucrose.

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Tomorrow I will discuss some questions regarding this topic and the syllabus overview, so do stay tuned

Here are the pictures of non-woody dicotyledonous plant. (roots, stem and leaf respectively in this order)

So that's all for today keep sparkling...💖

If you have any questions comment down below.