We mentioned yesterday that plants use scents to attract friendly and helpful insects and animals. They also use fragrances to protect against unfriendly visitors. Seemingly passive plants have secret weapons against insect invasions. We call it chemical warfare in the plant world.
A good example is the lima bean. Spider mites attack lima bean plants, but other predatory mites eat spider mites. When spider mites attack a lima bean plant, it floods the area with a chemical signal that attracts the predatory mites. This chemical odor also causes other lima bean plants to emit the same chemical. When the spider mites are gone, the plants stop secreting the chemical.
Some plants, such as tobacco and corn, protect themselves from destructive caterpillars by sending off a signal to attract wasps. Research has shown that plants customize the signal to attract a particular species of wasp. The wasps can tell the difference between the chemical signal of plants attacked by tobacco budworms and corn earworms, and different chemicals attract a different wasp species. So far, cotton, corn, and beets have been shown to have different emissions as they call for protection.
We previously mentioned wasps that kill and eat the caterpillars of certain butterflies. In that instance, ants have a symbiotic relationship with the caterpillars to protect them from the wasps in exchange for food. The U. S. Department of Agriculture is looking to find ways to cause one insect to combat another. This research is necessary because it can help us find ways to protect crops.
Chemical warfare in the plant world shows that God has equipped plants to protect themselves against different insect scourges. Because of that, we can survive on a planet where insectshopelessly outnumber us. The design that the Creator put into living systems is truly amazing.
One of our gardener friends sent us these interesting facts about plant design:
Seeds may be dropped into the ground upside down or sideways, yet the plants always come up to the surface.
One grain of corn will produce a stalk on which there may be two ears, with perhaps 742 grains on each ear.
A light crop of wheat will produce approximately 30 grains on each stalk. A good crop of wheat will produce approximately 60 grains on each stalk. There will always be an even number of grains.
Beans grow up a pole from left to right. Morning glories grow up a pole from right to left. If turned upside down, “twining” plants will uncoil and recircle their support. Guide a twiner in the “wrong” direction, and the plant will rewind itself. The higher the twiner grows, the more tightly it clasps its support.
Dandelions will grow above their surroundings whether the grass is two, ten, or twenty inches, for it must grow up into the sunlight.
An average watermelon will have ten stripes on it. Larger ones may have 12 to 16 stripes, but they always an even number.
Those of us who have grown sweet corn have almost always had to fight smut. That black and gray growth on corn looks disgusting. It is actually a fungus known scientifically as Ustilago maydis, and it has been around for a long time. Even though we dislike it, in some ways smut is a beneficial fungus.
Archaeologists studying ancient Puebloan people have found significant amounts of corn smut spores in their feces. That indicates that maize (corn) made up as much as 80% of the diet of ancestral Puebloan people and it included a great deal of the fungus.
One of the mysteries of ancient peoples in America is why they didn’t have nutritional diseases that were common in the world at that time. The most serious of those was the skin disease pellagra which is caused by a lack of niacin (vitamin B3) in the diet. The amino acid that prevents pellagra is missing from the maize but is present in high concentrations in the smut.
We generally have a negative attitude toward fungi, but there are many examples of beneficial fungus. Remember that penicillin was derived from a fungus. Now we find corn smut also offers a benefit. God has a use for everything He created, but sometimes it takes us a while to figure out what that use is.