Minerals in Plants

Keywords

fertiliser magnesium

mineral nitrogen phosphorus potassium

Lesson Objectives• State that fertilisers

contain minerals such as nitrates, phosphate, potassium and magnesium compounds.

• State what plants require these for.

• State that the production of many important compounds by plants requires elements that are obtained from soil.

Starter:Farmers who do not use artificial

fertilisers or pesticides are called organic farmers. Why are their foods more expensive to buy?

What are minerals for?

Plants use minerals from the soil to build the complex molecules they need to survive and grow.

Poor plant growth may be due to a deficiency of one or more minerals. Tests can be done to establish which mineral is deficient or a general purpose NPK fertiliser added..

What do you think NPK fertiliser is?

Plants need to build the complex molecules they need from minerals (elements and simple compounds), which they get from the soil.

Animals on the other hand get their complex molecules ready made from their food – they need very few minerals to supplement their diet.

What are minerals for?

Some examplesUses of different minerals

Open the OCR textbook to page p77 to 79

Read the information and then construct a table which details the minerals in a plant and the uses within the plant.

For the higher tier you will need to be able to explain what the minerals are used for within the plant.

Some examplesUses of different minerals

Feedback to the group

For the higher tier you will need to be able to explain what the minerals are used for within the plant.

Minerals in Plants

Keywords

fertiliser magnesium

mineral nitrogen

phosphorus potassium

Active transport

Lesson Objectives• Recall that minerals are

usually present in soil in quite low concentrations

• Explain that active transport can move substances from low concentrations to high concentrations (against the concentration gradient)

• Explain that active transport uses energy from respiration

Mineral Use Deficiency symptoms

Explanation

Nitrate ions (NO3) Building proteins and growth

Poor growth and yellow leaves

All amino acids contain nitrogen. Amino acids are the building blocks of protein.

Phosphate ions (PO4)

Respiration and growth

Poor root growth and discoloured leaves

A component of DNA molecules and cell membranes

Potassium ions (K+)

Respiration and photosynthesis

Poor flower and fruit growth, discoloured leaves

Must be present for photosynthesis and respiration enzymes to work

Magnesium ions (Mg2+)

Photosynthesis Yellow leaves Chlorophyll molecules contain magnesium ions. It's the magnesium that makes chlorophyll green.

How minerals are absorbed

• The concentration of minerals in the soil is very low. They dissolve in water and move around the soil in solution.

• How are root hair cells adapted to absorb water?

How minerals are absorbed

• Root hair cells are adapted to absorb the water out of soil by osmosis – they have a large surface area, thin walls and are close to the xylem cells used for transporting water up the plant. 

Phloem – uses ‘Translocation’

Moves food substances from leaves to rest of plant through columns of living cells

How minerals are absorbed

• Minerals cannot be absorbed by osmosis (which is the movement of water only) or diffusion (because the minerals are in very low concentration).

• The root hair cells have carrier molecules on their surface that pick up the minerals and move them into the cell against the concentration gradient. This requires energy, and is called active transport.

Active transport: In brief1. Active transport allows the plant to absorb minerals

against the concentration gradient. This is essential to its growth.

2. Active transport needs energy from respiration to make it work

Quick Quiz

1. Which element is needed to make chlorophyll green? _______

2. What is the symbol for a potassium ion?_______________

3. Which biological molecules contain nitrogen?_____________

4. Which mineral is part of a DNA molecule? ____________

5. One benefit of using NPK fertiliser in preference to farmyard manure is __________________________________

Plant mineral deficiency

This is a plant suffering from potassium deficiency

How can you tell?

Can you identify what is wrong with these plants?

Lack of nitrogen

Lack of magnesium

Can you identify what is wrong with this plant?

Lack of phosphorus