Flower The flower contains the organs of
plant sexual reproduction
It attracts insects needed to carry the pollen between plants to allow pollination
It's important for reproduction
Stem The stem is the organ which holds
the leaves upright in the air and facing the light
It carries water and minerals to the leaves, and food around the plant
The stem is important for nutrition, excretion and growth
Stem II Stem
Alternating system of nodes Locations where the leaves are
attached Internodes
Stem segments between nodes Auxiliary Bud
Angle, or axil, formed by each leaf of the stem
Has the potential to form a branch Most though are dormant
Stem III Growth of a young shoot is usually
concentrated at its apex (tip), where there is a terminal bud with developing leaves and a compact series if nodes and internodes
The presence of terminal bud prohibits the growth of the axillary bud Apical dominance
“evolutionary response that directs growth toward light
Leaf I The leaves are the sites of photosynthesis,
gas exchange and transpiration.
They make all the food that the plant needs
Leaves contain chlorophyll, which uses light energy to change carbon dioxide and water into glucose
They have tiny little pores, which allow essential carbon dioxide in and waste gases out
Leaves are important for nutrition and excretion
Leaf II The external structure of a leaf
consists of a flattened blade and a petiole Stalk Joins the leaf to the node on the
stem
Leaves are in various sizes, shapes and arrangement of leaves.
Roots The root is the organ which provides
anchorage for the plant so that it does not blow away or fall over
With its root hairs it provides a big surface area to help take in water and minerals from the soil - these are both essential for photosynthesis
The root is therefore important for nutrition
Root Hairs At the tip of roots, a vast number of
root hairs can be found. Why?
Most absorption of materials occur near the tips of roots
Increases the surface area of roots.
Root hairs are extensions of epidermal cells
Adventitious Roots Roots that develop out of above
ground stems or leaves are called adventitious roots These roots occur as of
adventitious tissue Tissue that grows in an atypical
location Provide additional support for
taller plants.
Modified Roots I Prop Roots
Develop from branches, or a vertical stem and grow downward into the soil to help support certain plants in an upright position Fichus tree South Florida?
Buttress Roots Swollen bases or braces that
support certain tropical rainforest trees that have shallow root systems
Modified Roots II Pneumatophores
Aerial “breathing” roots that may assist in getting oxygen to submerged roots
Contractile Roots Roots that grow into the soil and
then contract Pulling plant deeper into the soil
Corms bulbs
Relationships Mycorrhizae
Mutually beneficial associations between roots and soil fungi
Root nodules Swellings that develop on roots of legumes and house millions of rhizobia
(nitrogen fixing bacteria)
Root Graft Natural connection between the roots of trees belonging to the same or different
species.
Basic Morphology of Plants The basic morphology of plants
reflects adaptations that have developed so that an organism can inhabit and obtain resources from soil and air. More to come on organ systems
later.
Top Related