Photosynthesis: testing a variegated leaf for starch

This resource tackles the learning objective “Only areas of the plant with chloroplasts can make starch in photosynthesis”. This is activity 11 in the ‘Photosynthesis: A Survival Guide’ scheme and follows up from activity 10, ‘What are chloroplasts’.

Students carry out a starch test on a variegated leaf to demonstrate that only the parts containing chloroplasts are able to synthesise starch.

This resource is designed for 11-14 pupils but could be extended for use with older students as appropriate.

For a fun activity for an open evening or a science day, you can prepare ‘secret messages’ or hidden images on all-green pelargonium leaves for students to reveal by testing for starch, as shown in the video below.

You may wish to use this video clip, showing 19th century scientist Julius von Sachs’ pioneering research into how plants form starch from the BBC’s ‘Botany: A Blooming History series, available from the SAPS website.