WHAT'S STOMATA?

PURPOSE : To determine which side of the plant leaf takes in gases.

MATERIALS : Potted plant

                          Vaseline

PROCEDURE :

• Coat the top of four leaves with a heavy layer of vaseline.
• Coat the under side of four leaves with a heavy layer of vaseline.
• Observe the leaves daily for one week.
• Is there any difference in the two sets of leaves ?

RESULTS : The leaves that had vaseline coated on the underside died. The other leaves remained unchanged.

WHY ? Openings on the under side of the plant leaves called stomata allow gases to move into and out of the leaves. The vaseline plugged the openings and the leaf was not able to receive necessary carbon dioxide gas or eliminate excess oxygen gas.