Page 25 - The Miracle In The Seed

ll the different plants – from trees that are meters in height, to
the flowers whose fragrance you delight in and the vegetab-
A les and fruit you eat – all of them began as seeds. But what
stages have these seeds undergone in their formation?
In the development of the seed, the first stage is the transport of
the pollen, or male reproductive cells, of flower-bearing plants. Pollen
is transported by the wind, insects, animals or some other means to flo-
wers’ reproductive organs.
Right in the center of a flower is one or a cluster of female organs,
called the carpel. Each carpel consists of a tip called a stigma, carried
on a stalk called a style. At its base is a swollen ovary containing the
ovules that will develop into seeds.
Pollen from the male organs is deposited on the stigma, which is
coated in a sticky substance, and produces a pollen tube that reaches
down the style to the ovary. This sticky surface has the very important
function, for if the pollen does not reach the ovary, it cannot fertilize
the ovules. The sticky surface of the stigma catches pollen and pre-
vents it from being dispersed and wasted.
Once the grain of pollen, or male reproductive cell, lands on the
stigma of a flower from the same species, the pollen produces a tube li-
ke a fine root growing down the neck of the style to the ovary. Each of
the mature pollen grains contains two sperm cells. The pollen tube
transports the sperm to the ovule. One sperm cell fertilizes the egg in
the embryo sac of the ovule, resulting in the development of a seed.
The other sperm cell unites with two cells in the embryo sac, creating
the tissue that surrounds the embryo and provides nourishment for it.
Shortly after this process, called fertilization, a seed is produced.
Every seed contains a plant embryo and a store of nutrients. In
this embryo is contained all the information relating to the future
plant, as we explained at the start. That is to say, the embryo contains a
small copy of the plant; and the store of nutrients enables this embryo
to grow until the plant can produce its nourishment.