PLANT STRUCTURES

Kinds of Plant Tissue:

______________________ tissue - tissue capable of unlimited division

Apical meristems produce the most growth.

Lengthening of roots and stems by apical meristems is called ____________________.

Widening of roots or stems is called ______________________ .

Cells produced by the meristems become specialized by a process called ______________________. Cells differentiate into 3 kinds of tissue, Epidermis, Vascular tissue, and Ground tissue.

EPIDERMIS - outermost layer, protective, retains moisture.

______________________ - conducts food, water, and minerals.

______________________ - conducts water and minerals. consists of two kinds of conducting cells, TRACHEIDS and VESSELS. The cytoplasm in vessels and tracheids dies at maturity leaving hollow tubes for water and minerals to pass through.

______________________ - conducts food

Phloem cells are called ______________________ because their end walls look and act like sieves. Sieve tubes are living cells that have no nuclei. Each one

has a companion cell that supports it.

______________________ - unspecialized tissue that cushions and protects vascular tissues from injury, and stores food and water. This tissue usually consists of two concentric circles of tissues called pith and cortex. The pith is made of spongy cells called ______________________. The cells of the cortex is more rigid.

ROOTS

3 Functions:

1. ______________________

2. ______________________

3. ______________________

Root Systems:

________________ = first root produced

________________ - a large primary root with many smaller secondary roots branching from it.

________________ - primary root dies and is replaced by many equal secondary roots.

________________ - develop from stems

________________ - absorb water from air

Root Structure

3 layers:

• ______________________ - forms protective layer, produces root hairs which absorb water by osmosis. Root hairs increase the surface area of the root. One plant may have 14 billion root hairs.
• ______________________ - made of loosely packed cells except for the inner layer of cells called the ENDODERMIS. The endodermis is tightly packed. The cells have a waxy ring around them to make water flow through them not around them.

• ______________________ - contains xylem, phloem, and two special layers of meristematic cells.
• Pericycle produces the secondary roots.
• Vascular cambium - produces new xylem and phloem

The major sections of a root tip are:

Root cap - protects

Root ______________________ - dividing cells

Region of elongation - area where cells may grow up to 10 times in length.

Region of differentiation - cells change into different tissues.

STEMS

Stems transport food, water, and minerals between the roots and leaves

Structure of Stems:

Stem structure, like root structure, is made of epidermis, vascular tissue, and ground tissue. The vascular tissues are arranged in groups called vascular bundles.

In ______________________, vascular bundles are scattered.

In ______________________, vascular bundles are arranged in a ring.

_________________ - have little or no secondary growth, supported by turgor pressure.

Woody stems - vascular cambium produces new layers of xylem each year. Each year's xylem is divided into spring wood and summer wood

___________ wood - made of larger vessels

___________ wood - made of smaller vessels

___________ - nonfunctioning older xylem that becomes plugged with gums and resins.

___________ - active xylem

Cork cambium is a region of meristematic tissue that produces the cork cells that together with the phloem make up the bark.

________ - protective structures that develop around the meristematic tissues on twigs.

____________ - located on ends of twigs; lengthen the stem.

____________ - located on sides of twigs, may produce leaves, flowers, or new twigs.

Stem Adaptations:

______________________ - climbing stems

______________________ - horizontal stems that produce new plants.

LEAVES

Structure of the leaf:

______________________ - broad flat part

______________________ - leaf stalk

______________________ - conducting tissue in leaves

Simple leaf - blade is undivided

______________________ - blade is divided into leaflets.

Compound leaves may be pinnately or palmately arranged.

_____________, the arrangement of the veins, may be pinnately or palmately arranged.

Epidermis - outer layer of cells

_______________ - waxy layer produced by epidermis

_____________ - openings in the epidermis that allow gas exchange

___________ cells - kidney-shaped cells that open and close the stomata

___________ - the middle portion of the leaf

___________- a row of closely packed cells that contain chlorophyll in the upper

mesophyll

___________ - a group of loosely packed cells that contain chlorophyll in the lower mesophyll

Vascular bundles - groups of xylem and phloem that form the veins in the leaf.

____________ - keep their leaves all year

____________ - lose their leaves in winter

Abscission - the shedding of leaves

____________ - the evaporation of water from a leaf.

Ninety percent of water absorbed through the root is lost by transpiration.

Transpiration, Osmosis, and Cohesion pull water upward through the stem.