Why Do Plants
are used by a plant to have kids....er.....seeds, and new baby
plants. Male parts of the flower make pollen,
which is a yellow dust that contains all kinds of information
on being a plant just like Dad. Female parts make ovules,
which contain all kinds of information on how to be just like
Ma. Nature likes to mix information from both parents when it
makes a kid; it's the same for plants as it is with animals. If
the information didn't get mixed, all the kids would be identical
to the single parent who made them... all the flowers would be
the same shape, the same height, the same color.....BORING!
problem...how do you get the pollen and the seed together? It
is not like they can get together in the same place like animals.
Imagine a strange rose bush pulling up to your garden gate and
asking the plant in your yard for a date? Tell the bush to have
her back by 10.00pm and keep his thorns to himself? Nah....
plants reckoned.. "If I can't move from this spot, why can't
I get someone else to carry my pollen over to that nice little
sapling over there, swaying in the breeze." But how??
plants have found several way to do it. Oak trees and pine trees
use the wind, scattering their pollen in clouds hoping that some
would hit where needed. Others bribe insects to carry the pollen
away. The bribe is honey money, so to speak. The insect, perhaps
a bee, is attracted by the fragrance of the flower, which tells
it that there is nectar to be had. Nectar will
become honey in the bee's hive. So the bee does a quick sniff,
or maybe is tempted by the bright color of the flower, and arrives
for the free gift.
not so fast, Ms. Bee. The nectar is hidden way, way down, and
you are going to have to climb right down deep inside, amongst
those sticky-up stamen things. And Mr. Bee gets
covered in the pollen which is produced on the stamens.
Stamens are the male part of the flower, which produce
the pollen, which has all the information on
the Dad-part of the flower. So, after visiting flower number one,
the bee goes to visit flower number two. And some of the pollen
from the first flower gets spilled into the second flower. The
second flower might also give some pollen to the bee, but with
luck, some of the pollen from the first flower will land on the
stigma. The stigma is the female
part of the flower, and is designed to carry the pollen
down to a deeply hidden ovary at the base of
the style, which is a tube connecting the ovary
to the stigma.
a flower be both Ma and Dad at the same time? No problem. In fact
some flowers can actually fertilize themselves,
while others are just female or just male like us human types.
But most flowers don't want to be a mirror image of a single parent,
which is how they would end up if they mixed the pollen
and ovum (the female part of the seed-to-be)
that they had produced themselves. If all the flowers in a field
were exactly the same, and one got sick, then maybe they ALL would
get sick if they were exactly alike. The plant puts its female
and male parts in places where it would be hard for a single insect
to mix the pollen and ovum from
the same plant. The plant often forces a visiting insect from
another plant to put the pollen on the stigma
before it can reach the pollen on the stamens.
Vive La Difference!
Yes. Well Anyway....
take a look at how the flower is constructed. I will only show
you one particular flower design, but they mostly use the same
general layout. From the outside you see the petals
and the sepals.
pull two of the petals off and look inside!
the female part of the flower is in the very center, and is called
the carpel or pistil (pssst!
botanists never agree on the name of anything, and come up with
real WEIRD words anyway!!!). The male stamens
are in a ring around the carpel (or pistil).
we will take a closer look at the carpel - pistil
and the stamens. The pollen
is made in the special anther cells at the top
of the stamens, and the filaments
help arrange them so that the flower does not pollinate or fertilize
itself. The ring of stamens is called the androecium.
The stigma at the head of the style
receives pollen (the process is called pollination),
which moves down the pollen tube to the ovary,
where the female part of the flower has produced an ovum.
The pollen combines with the ovum,
fertilizing it and making a whole out of the seperate Ma and Dad
parts of two different plants. The result is a seed,
which is really a complete plant waiting in a shell for the conditions
to be right for sprouting. Just add water, warmth, and the kids
take a peek at an insect entering a flower. See how the insect,
a moth of considerable artistic deficiency in this case, is entering
the flower and touching just the stamens, but
not the carpel. It is possible that the last
flower puts pollen on the moth's rear end ("the bug butt"
to kids unfamiliar with insects), so it will spread the pollen
on the stigma while receiving new pollen
from the stamens.