Germination
Seeds remain dormant
or inactive until conditions are right for germination.
All seeds need water, oxygen, and proper temperature in
order to germinate.
Some seeds require proper light also. Some germinate better
in full light while others require darkness to germinate.
When a seed is exposed to the proper conditions, water
and oxygen are taken in through the seed coat. The embryo's
cells start to enlarge. Then the seed coat breaks open and
a root or radicle
emerges first, followed by the shoot or plumule
that contains the leaves and stem.
Many things can cause poor germination. Overwatering causes
the plant to not have enough oxygen. Planting seeds too
deeply causes them to use all of their stored energy before
reaching the soil surface. Dry conditions mean the plant
doesn't have enough moisture to start the germination process
and keep it going.
Some seed coats are so hard that water and oxygen cannot
get through until the coat breaks down. Soaking or scratching
the seeds will help break down the seed coat. Morning glories
and locust seeds are examples. Other seeds need to be exposed
to proper temperatures. Apple seeds will not germinate unless
they are held at cold temperatures for a period of time.
Do
all plants use seeds to reproduce? When
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