IBDP Biology- Mineral ions absorption and the root system

For this IBDP Biology Blog post, we will be looking at how the plants and the structure of it is able to absorb minerals, let's go!

How mineral ions in the soil move into the root  

Minerals move into the root system via the following pathways:

Diffusion: 

• Movement of minerals along a concentration gradient

Mass Flow: 

• Uptake of mineral ions by means of a hydrostatic pressure gradient
• Water being taken into roots via osmosis creates a negative hydrostatic pressure in the soil
• Minerals form hydrogen bonds with water molecules and are dragged to the root, concentrating them for absorption

Fungal Hyphae:

•   Absorb minerals from the soil and exchange with sugars from the plant 

(mutualism) 

Explain the process of mineral ion absorption  

• Fertile soil invariably contains - charged particles to which + charged minerals may attach
• Root cells contain proton pumps that actively pump H

⁺ ions into the surrounding soil, which displaces the positively charged minerals allowing for their absorption (the negatively charged minerals may bind to the H+ ions and be reabsorbed with the proton)

• This mode of absorption is called 
• indirect active transport - it uses energy (and proton pumps) to establish an electrochemical gradient by which mineral ions may be absorbed via diffusion
• Alternatively, the root cells may absorb mineral ions via 
• direct active transport - using protein pumps to actively translocate ions against their concentration gradient  

Identify modifications of roots, stems and leaves 

• A storage organ is a part of a plant specifically modified to store energy (e.g. carbohydrates) or water
• They are usually found underground (better protection from herbivores) and may result from modifications to roots, stems or leaves:
• Storage roots: Modified roots that store water or food (e.g. carrots)
• Stem tubers: Horizontal underground stems that store carbohydrates (e.g. potato)
• Bulbs:Modified leaf bases (may be found as underground vertical shoots) that contain layers called scales (e.g. onion)
• Some plants (called succulents) have modified leaves or stems (thickened, fleshy and wax-covered) to enable water storage (e.g. cacti)
• Other plants (e.g. vines) have modifications to their leaf or stem to enable climbing support and attachment - these are called tendrils 

That is all!

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References:

• https://www.google.com/url?sa=i&url=https%3A%2F%2Fpmgbiology.com%2F2015%2F03%2F21%2Fmineral-ions-in-plants-a-understanding-for-igcse-biology%2F&psig=AOvVaw2liGlgmLwubVITQBkTuiiO&ust=1627135149261000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCOjkvPes-fECFQAAAAAdAAAAABAD
• https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.open.edu%2Fopenlearn%2Fnature-environment%2Fnatural-history%2Fsurviving-the-winter%2Fcontent-section-1.4.2&psig=AOvVaw0e2MXgm1YHnAHK2fc6W6H_&ust=1627135250346000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCLi56bSt-fECFQAAAAAdAAAAABAL

Drafted by Venetia (Biology)