Garden Warfare: How Plants Protect Themselves from Predators

An interesting thing about plants is that they all have some sort of defense mechanism against their predators. These defense mechanisms can appeal to several senses: touch, smell, and taste. Some plants even have multiple defense mechanisms.

I decided to walk around the garden and search for these defenses on some of the crops that we grow.

For me the most apparent defense system is that of squash and zucchini plants.

If you look closely the stems and leaves of the zucchini plant are covered in translucent thorns. These thorns act as protection for the plant. The thorns that cover the bottom of the leaves and the entire body of the vines keep the plant safe from bugs and other predators that would like to eat the green flesh. The thorns are also very irritating for human flesh. I would recommend wearing gloves when harvesting squash (though I think I need to listen to my own advice.)

Squash also has a scent-mechanism. When I am picking squash or zucchini in the garden I notice the acrid smell that rubs off on my hands and sleeves. This is another form of protection that the plant uses. For instance, the stench of squash and zucchini plants is known to ward off deer. So if you or someone you know is having a problem with deer eating crops in the garden, there is always the option of planting squash around the appetizing plant to fend off the deer.

Another crop that we grow in the garden that has defensive mechanisms is the cabbage. When a cabbage leaf is cut or eaten by a predator, the cabbage will emit a gas—methyl jasmonate. This gas sends a signal to the cabbages around it. When the signal is received, the nearby cabbages exude toxic chemicals in their leafs to ward off the potential predator that is noshing on the cabbages.

Plants also alter their flavor to protect themselves. Fruits and vegetables that have tannins, or tannic acid, in them, use this compound to protect themselves. There are several crops in the garden that contain tannins. These include: beets, cabbage, collard greens, spinach, peas, pumpkins, and zucchini. The tannins are more present when the fruit is unripe. Therefore the plant is protecting itself from being eaten before it is fully ripe so that the seeds will be fully developed when they proceed to the exterior world beyond the fruit.


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