Page 23 - Demo 1

PLANT TISSUES

Plants have a high level of structure called plant ssue systems. A plant
ssue system can be defined as a funconal unit, which connects all organs of a
plant. Like animal ssue system, plant ssue system is also grouped into various
ssues based on their funcons.

The ssues of a plant are http://cdn.biologydiscussion.com/wp-
content/uploads/201
organized into three ssue systems: the 6/02/clip_image002-73.jpg
dermal ssue system, the ground ssue
system, and the vascular ssue system.
Dermal ssue forms the outer protecve
covering of the plant. Ground ssue fills
the interior of a plant and helps carry
out the funcons of the different organs.
Vascular ssue provides support and
transports water and nutrients within
the plant. Each major ssue type is made
up of disncve kinds of cells, whose
structures are related to the funcons of
the ssues in which they occur.

Dermal Tissue Figure 5. Plant Tissues
Source: http://www.phschool.com/science/
biology_place/biocoach/plants/images/3tisscut.gif

Like skin, all parts of the outer
layer of a plant are lined by an
epidermis, a layer of closely packed

cells that act as a protecve covering.
Figure 6. Epidermal layers lined with cucle:
A – in fruit of Citrus sinensis The epidermis is one cell layer thick
B – in fruit of Malus pumila and provides an effecve barrier
C – in Dracaena stem against water loss.
D – in leaf of Dasylirion serrafolium
Source:
The wall of epidermal cells that are exposed to air are covered with a
waxy layer called the cuticle, which protects against ultraviolet light damage
and water loss. The cucle also offers protecon against bacteria and other
organisms that might cause disease.

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