Why do plants die?
Name: Rod Diercks
Our fourth grade class is studying plants. Why do plants die?
The point of the life of most plants is to reproduce. Once the plant has
produced seeds, it has done what it is supposed to do. Of course, not all
plants die either, at least not right away. The redwoods in California are
extremely old and some creosote plants in the desert are really old too.
Some plants in areas where the climate has both hot and cold weather
look like they die in the winter, but they are just resting until the
spring. Tulips, for instance, don't actually die, the bulb lives in the
ground, and the green part of the plant comes up each spring. Some plants
actually do die, not because it is their time to die, such as after
reproducing, but because of disease, lack of water or food, or due to
pests. Plants can be weakened by animals eating them or insects damaging
them. They can also be killed by other plants making the place where they
grow too shaded, or taking all the nutrients or water. Therefore, plants
compete with one another for survival.
I would just like to add a bit to Stacie's comment. Plants per se,
do not have what we commonly call a 'life-span'. Given optimum conditions,
they can theoretically live for an indeterminate time. What does happen,
however, is that as plants age they might be more inclined to break
for example from drying or simply increased chance of being hit by
some random accident. Breakages can introduce disease-causing pathogens
which can then move throughout the plant. Environmental stresses, such
as poor nutrition or extremes of temperature can cause dieback, and these
areas of dead tissue might once again allow for entry of pathogens.
Frequently when plants are stressed they seem to be noticed by insects
who then finally finish them off.
Gardeners often use plant propagation, which is basically taking a small
part of a plant and growing it into an entirely separate plant. This
smaller version of the original could be saved if something happens to the
original parent plant.
Hope this info helps!
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Update: June 2012