Transcript lesson
Lesson 4 : Roots, water and minerals Lesson aims • Pupils study the uptake and movement of water in plants, looking at root structure, path through plant and importance of minerals. • Respiration in root cells is also considered. Lesson outcomes By 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 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 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? Draw diagrams to describe your observations and answer these questions Spectrum Biology P.134-137 may help C A B D E 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: Root hair cells Large surface area Thin cell membrane 1.Why do you think plants take in oxygen through their roots? 2. Why do plants take in minerals through their roots? The three main types of nutrient are: 1. Nitrogen in the form Nitrates – used to make proteins 2. 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 plant Describe how roots are adapted to take in water - branched, root hairs, large surface area Why do root cells require oxygen from air in soil? Can you describe how plants use water? photosynthesis, transport minerals, for cell growth, form fruits, cool leaves Do you know why plants need minerals? Homework Draw a poster explaining why plants need phosphates, nitrates and potassium. Show what happens to a plant if it suffers from a deficiency of each nutrient.