Lesson 4 : Roots, water and minerals

Lesson aims

•To study the uptake and movement of water in plants, looking at root structure, path through plant and importance of minerals.

Lesson outcomesBy the end of the lesson pupils should • be able to describe how substances from

soil enter and move through a plant• describe how these substances are used• be able to describe how roots are

adapted to take in water• know root cells require oxygen for

respiration from air in soil

Plant growthPlant growth

Plants grow using food they make through photosynthesis. So what else do they need?

Plants also need three important minerals to keep healthy. They absorb these through their roots.

Roots The roots of a plant provide:• A way of getting water from the ground.• Stability for the plant by anchoring it into the ground.

The water absorbed by the plant is used for:• Photosynthesis.• Keeping the plant rigid (turgidity)• All the chemical reactions in the plant• To move dissolved minerals (nitrates) to cells

The passage of water through plants Draw diagrams to describe your

observations and answer these questions

1. Roots How do the roots get a large surface area ? Why

is this helpful?2. Stem How does water and nutrients travel from the

roots to the leaves 3. Leaves How can water escape form leaves?

Spectrum Biology P.134-137 may help

A

B

C

D E

Root hair cells

Plant roots are made of “root hair cells” which have a large surface area and a thin cell membrane to help absorb the minerals, water and oxygen:

Thin cell membrane

Large surface area

1.Why do you think plants take in

oxygen throughtheir roots?

2. Why do plants take in mineralsthrough their

roots?

The three main types of nutrient are:The three main types of nutrient are:1. Nitrogen in the form Nitrates –

used to make proteins2. Phosphorus in the form of

Phosphates – used to provide phosphorus to help photosynthesis and respiration

3. Potassium – helps the enzymes that are needed for photosynthesis and respiration

Lack of the three minerals would lead to a “Deficiency Symptom”:

Lack of nitrates:Small plant, yellow leaves

Lack of phosphates:Small roots and purple leaves

Lack of potassium:Yellow leaves with dead bits

Can you?Describe how substances from soil enter

and move through a plantDescribe how roots are adapted to take in

water

Why do root cells require oxygen from air in soil?

Can you describe how plants use water?

Do you know why plants need minerals?

- branched, root hairs, large surface area

photosynthesis, transport minerals, for cell growth, form fruits, cool leaves

HomeworkDraw a poster showing every thing

you know about plants (include why plants need phosphates, nitrates and potassium and happens to a plant if it suffers from a deficiency of each nutrient)