Microscopy of pear pulp sclereids: staining to identify molecules

This activity uses the coarseness of pear (Pyrus sp.) pulp to show the value of using stains to identify the presence of particular molecules, using the microscopic exploration of pear pulp tissue to answer the question ‘What gives pear pulp its rough texture?’

A simple method is provided in the PowerPoint presentation that first asks students to look at a pear pulp scrape under the microscope. They see clusters of cells called sclereids and then build up evidence that it is these that are responsible for the coarseness of the pulp. They see that sclereids are absent from the pulp of apples (Malus sp.) and then that the walls of the sclereids are strengthened with lignin and so are much harder than non-lignified cells.