Allelopathy is the ability of one plant to chemically inhibit another plant, due to the release into the environment of substances acting as germination or growth inhibitors. A recent article from the University of Florida Extension Service reviews the research. A review of the chemical basis for the inhibition is complex, involves a number of different chemicals produced by the plants and (lucky for you!) is outside the scope of what we can cover here. But the biological effects can affect many aspects of plant ecology, including occurrence, growth, plant succession, the structure of plant communities, dominance and plant productivity. So, chemical warfare between plants can determine what grows where, what can grow alongside what, and what grows at all! Virtually any part of the plant can have the ability to produce these chemicals over the course of the growing season. So, flowers may be the assassins during one part of the year and the leaves of the same plant may be the assassin later in the year. Just to keep you on your toes, the flower may use one chemical and the leaf another for the inhibiting effect even though they are on the same plant!
It appears that one of the weapons that invasive plants may have in their arsenal is their ability to suppress other plants so that the invasive has an advantage. Some ecosystems may be dependent on certain plants that grow there naturally to inhibit the growth of plants not normally found in that ecosystem—sort of a “clique” of plants that won’t let the new guy join. Some plants have the ability to inhibit everything around them except their own seedlings. Stranger yet, some plants, like mesquite are reputed to inhibit the germination of their own seeds. So, you cut down the big mesquite trees in your yard because you sure didn’t want more of those only to find that with the mature tree gone, about a million mesquite beans germinated!
The ramifications of all this are pretty interesting. We all worry about GMO’s. What if they could make a corn plant that inhibited weeds from growing in its field?
So, can we infer that the reason you have never been able to get that rose to grow in that particular spot in your garden isn’t that it doesn’t like the soil, the amount of sun or how much water it’s getting, but because it just wouldn’t be caught dead growing next to whatever else you have planted there? Well, maybe so!
Next month, I’ll be writing about an allelopathic effect that you have already heard about but which there seems to be a lot of confusion—the reputed toxicity of black walnut trees because of the presence of the chemical juglone in their leaves and nuts. Just to give you a little review, that same chemical is present in pecans and hickories.
It appears that one of the weapons that invasive plants may have in their arsenal is their ability to suppress other plants so that the invasive has an advantage. Some ecosystems may be dependent on certain plants that grow there naturally to inhibit the growth of plants not normally found in that ecosystem—sort of a “clique” of plants that won’t let the new guy join. Some plants have the ability to inhibit everything around them except their own seedlings. Stranger yet, some plants, like mesquite are reputed to inhibit the germination of their own seeds. So, you cut down the big mesquite trees in your yard because you sure didn’t want more of those only to find that with the mature tree gone, about a million mesquite beans germinated!
The ramifications of all this are pretty interesting. We all worry about GMO’s. What if they could make a corn plant that inhibited weeds from growing in its field?
So, can we infer that the reason you have never been able to get that rose to grow in that particular spot in your garden isn’t that it doesn’t like the soil, the amount of sun or how much water it’s getting, but because it just wouldn’t be caught dead growing next to whatever else you have planted there? Well, maybe so!
Next month, I’ll be writing about an allelopathic effect that you have already heard about but which there seems to be a lot of confusion—the reputed toxicity of black walnut trees because of the presence of the chemical juglone in their leaves and nuts. Just to give you a little review, that same chemical is present in pecans and hickories.