SASS Bio Transport in Flowering Plants Handout

ST ANDREW’S SECONDARY SCHOOL Chapter 9: Transport in Flowering Plants 1 Name: ______________________________( ) Class: ______________ Date: __________ The Tallest of Them All Topic: Nutrition and Transport in Flowering Plants Student’s Handout  Aims At the end of this lesson, you should be able to…  explain how the structure of the xylem enables water to move up the plant,  explain how the leaves are responsible for moving water up the plant,  identify the surface of the leaf that plays a bigger role in moving water up the plant  explain how the number of stomata affects the rate of transpiration in the plant.  Safety Handle capillary tubes with care. Inform your teacher immediately if there is any breakage. Refrain from handling the broken glass pieces on your own.  Activity Handout A: Investigating How Water Travels Up a Plant The tallest tree in Singapore is found in Bukit Timah Nature Reserve. Known as the Seraya tree (Shorea curtisii), it can grow up to a height of 60 m, which is equivalent to a 20-storey HDB block! How is water able to travel against gravity, from the roots, through the xylem to the leaves at the top of such tall trees? In this activity, you will be investigating the features that enable water to travel up a plant.

ST ANDREW’S SECONDARY SCHOOL Chapter 9: Transport in Flowering Plants 2 Investigation 1: How does the structure of the xylem enable water to move up the plant? In this investigation, the straws and capillary tube are used to model the xylem. Materials  1 large straw  1 regular straw  1 capillary tube  1 half of a petri dish  10 mL of coloured water  1 ruler  1 marker 1. In Table 1.1, trace the circumference of the large straw, regular straw and capillary tube. 2. Use the ruler to measure the diameter of the outline you have drawn. Record your measurements in Table 1.1. 3. Fill the petri dish with the coloured water. 4. Place the large straw into the petri dish with one end firmly on the base of the petri dish (Fig. 1.1). 5. Using the marker, mark out the height that the coloured water travels up to (i.e. height of the coloured water column) in the large straw. 6. Use the ruler to measure the height of the coloured water column. Record your measurement in Table 1.1. 7. Repeat steps 4 to 6 with the regular straw and capillary tube. Fig. 1.1 coloured water petri dish straw

ST ANDREW’S SECONDARY SCHOOL Chapter 9: Transport in Flowering Plants 3 See  What is the diameter of each straw/tube?  What is the height of the coloured water column in each straw/tube? Table 1.1 Circumference outline Diameter (cm) Height of coloured water column (cm) Large straw Regular straw Capillary tube Think  What is the relationship between the diameter of the straws/tube and the height of coloured water column?  Which straw or tube best represents the structure of a xylem? Why? Wonder  How does a tube with a narrower lumen allow water to travel up the plant?  How well does t