Agriculture Reference
In-Depth Information
How Plants Survive
Plants are exceptionally good at surviving. Some have thorns to ward off animals. Some
have thick bark, or thick hair, or wax on their leaves. They build themselves with ingredi-
ents that are difficult for microbes to digest.
When their branches get injured, they just discard them and grow a new one. Before they
drop them, they make sure to build a strong scar, often with toxic chemicals, so predators
can't get in. This is one reason why we don't necessarily want to prune all damaged plant
parts or the leaves and flowers of our perennials after flowering that are turning brown. The
plant will drop them when it's ready.
Plants produce chemicals for defense. Some of them are kept in a special storage area of
the plant to be moved and used only when needed. Others chemicals are in the leaves all
the time. Some are produced as more of a general feeding deterrent and some are quick-act-
ing poisons. Hydrogen peroxide is used to counteract enzymes secreted by certain patho-
genic fungi, while other chemicals just kill the fungi directly.
Some of these chemicals become our pharmaceuticals and pesticides. Salicylic acid is
abundant in many fruits and vegetables when they are grown on healthy soil. Aspirin uses a
synthetic alternative, acetylsalicylic acid, that causes all kinds of horrible side effects. I can
follow my doctor's advice and take aspirin every day if I want to experience some of these
side effects, or I can eat fruits and vegetables grown on healthy soil.
Some plants employ others to help defend them — bacteria, fungi, and even insects. One
of the most famous insect/plant examples is the ant/acacia relationship. Certain species of
acacia trees provide homes and food for ants, who in turn protect the plant from insects and
even herbivores. They even prune away other plants that are getting too close. More com-
mon to all plants, bacteria and fungi colonize them from head to toe, protecting them in ex-
change for food.
Different kinds of plants have different survival strategies. Some plants, especially annu-
als, survive by simply growing really fast to get above plant-feeding animals and by produ-
cing tens of thousands of seeds from each flower. Longer-lived plants spend more time
building strong root systems, difficult-to-digest plant parts and bark, and toxins.
The reason it's good for us to learn about all of these things is because in order to pro-
duce strong bark, build strong leaf scars, produce toxins, cooperate with other species, and
produce many seeds, plants need healthy soil. Plants are exceptionally good at surviving, if
they have the raw materials they need.
