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Plants
9.3 Growth in Plants
Growth in Plants
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Undifferentiated cells in the meristems of plants allow
indeterminate growth
Many plant cells have the capacity to generate whole
plants (totipotent).
Growth in plants is confined to regions known as
meristems.
Meristems = composed of undifferentiated cells that
are undergoing active cell division.
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Primary meristems are found in the tips of stems and roots
= APICAL MERISTEMS
Many dicotyledoenous plants also develop lateral
meristems.
Growth in Plants
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Mitosis and cell division in the shoot apex
provide cells needed for the extension of the
stem and development of leaves.
Activity: Think-Pair-Share. Recall the stages
of Mitosis and cell division. Write down what
you can remember. Talk with your seatmate.
Discuss with class.
Growth in Plants
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Mitosis and cell division in the
shoot apex provide cells needed
for the extension of the stem and
development of leaves.
Cells in meristems are small and
go through the cell cycle
repeatedly to produce more
cells.
The new cells absorb nutrients
and water and increase in
volume and mass.
Growth in Plants
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Mitosis and cell division in the
shoot apex provide cells needed
for the extension of the stem and
development of leaves.
The root apical meristem is
responsible for the growth of the
roots.
The shoot apical meristem
produces cells needed for the
growth of the stem and also cells
that will develop into leaves and
flowers.
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Young leaves appear as small
bumps known as “leaf primodia”
Growth in Plants
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Mitosis and cell division in the
shoot apex provide cells needed
for the extension of the stem and
development of leaves.
Protoderm = cells that will give
rise to epidermis.
Procambium = cells that give
rise to vascular tissue.
Ground meristem = cells that
give rise to pith.
Chemical influences play a large
role in determining the type of
specialized cell.
Growth in Plants
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Plant hormones control growth of the shoot apex.
Hormone= chemical message produced in one part of an
organism and has an effect in another part.
Auxins = plant hormones with a broad range of
functions including:
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Initiating the growth of roots
Development of fruits
Regulating leaf development
Growth in Plants
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Read about the effects of auxin pages 424-428
Complete Data question pg 424