Page 102 - The Miracle In The Seed

THE MIRACLE IN THE SEED

When the seed starts germinating, it draws water from the earth,
and the embryo cells start dividing. Then the seed coat opens. Little
roots, the first outward sign of the plant’s root system, emerge and
grow down into the earth. As the roots grow bigger, the earth starts to
restrict them. But although subjected to extreme pressure, they are not
damaged, since the newly forming cells at the tips of the roots are con-
stantly active and provide protection as the root moves through the
hard earth particles. The cells behind this protective layer (calyptra)
have the ability to divide very swiftly and let the root grow by up to 11
cm a day. The roots branch as they develop, providing a greater surface
area to take in water, while serving to anchor the plant more firmly in
the earth. In addition, the tiny root hairs play an important role in in-
creasing the plant’s capacity to draw essential minerals from the earth. 54

Due to the stimulation of
gravity, a plant’s roots grow
quickly down into the earth.
Absorbing root hair The tips of the roots are
Cell growth
formed from the meristem tis-
Mature sue, which is capable of swift
root
division for growth. This tis-
sue is protected by a cap (ca-
lyptra) consisting of
Calyptra
parenchyma cells that pro-
duce a substance called mu-
cilage, easing the passage of
the roots into the earth while
Epidermis Endodermis speeding up the absorption of
certain ions from the earth.
Pericycle New cells formed by the divi-
Parenchyma
sion of the meristem tissue
allow the roots to lengthen. In
addition, these cells diversify
as they mature, taking on the
Phloem
roles of transportation, stor-
Apical
meristem age or epidermal cells, de-
pending on their location.
(Ozet, Arpac›, Biology 3, p.
Coleoptile 48.)