What do opium, maple syrup and natural chewing gum have in common? Although these substances have completely different uses and effects on humans, they all come from similar plant-based chemicals.
Latex is a common name for certain types of emulsions, or blends of at least two liquids that don’t typically mix. With latex that comes from trees, the component substances include tiny polymer particles floating in water-based solutions. Polymer molecules, which feature long structures with many repeating subunits, are known for their strength, flexibility and presence in most synthetic plastics. In plant latexes, natural polymers combine with a range of proteins, sugars, starches and other substances to give different materials their key characteristics.
Latex isn’t the only useful fluid that comes from trees. For instance, pine trees produce a sticky, turpentine-containing material called resin, which helps give them their characteristic smell. When dried, resins can leave behind another wax-bearing substance called rosin, which people have used for everything from keeping old wooden ships watertight to treating violin bows and strings for smoother sounds. In ancient times, huge conifer trees created massive quantities of resin that often trapped insects and bacteria. Much of this dried resin still survives today as fossilized amber that provides us with insights into what life was like 30 million years ago.
Why do many plants make natural latex and resin? It’s not just to ensure that humans have plenty of sustainable rubber, wood finish, medicine or pancake syrup. Thanks to their sticky, gummy nature, these liquids make a great defense against plant-eating herbivores, like bugs. When these attackers burrow into trees and other plants, the thick fluid that comes out dries to create a tough seal. This helps protect the vulnerable wound and slows down further feeding activity.