VASCULAR PLANTS CELLS TISSUES ORGANS FORM AND FUNCTION

VASCULAR PLANTS CELLS TISSUES ORGANS

FORM AND FUNCTION l Everything about a vascular plant is geared towards one process… l PHOTOSYNTHESIS l CO 2 + H 2 O C 6 H 12 O 6 + O 2

PLANT CELLS l Recall: plant cells have cell walls, chloroplasts and large central water vacuole.

OVERVIEW – ROOT AND SHOOT SYSTEM l l Root system is below the ground Shoot system is above the ground and can include stems, leaves and sometimes flowers.

ORGANS l l Leaf: primary site of photosynthesis Stem: conduction of water and dissolved minerals and sugars and structure and support Root: anchorage; absorption of water and dissolved minerals Flower: seed production

TISSUES l l Each type of tissue is continuous throughout the plant structure Each tissue contains cells that are adapted to perform a specific function

GROUND l Has multiple functions and makes up most of the inside of a plant – – – Parenchyma: storage, photosynthesis, gas exchange, protection, tissue repair and replacement. Collenchyma: support surrounding tissues, provided flexibility for plant, tissue repair and replacement Schlerenchyma: support of the mature plant

DERMAL l the outer layers of cells that form a protective covering for the plant – Includes the epidermis and the periderm l Guard cells are cells found in the upper and lower epidermis of leaves and perform gas exchange through the stoma (hole)

l Trichomes – tiny growths on the leaves and stems of some plants that can make the plant appear fuzzy or wooly. Help keep leaf surfaces cool and some secrete toxic substances that repel herbivores.

l Root Hairs: fine hair like structures that cover the surface of the root of a plant. They increase the surface area available for gas exchange and absorption of water by the roots.

VASCULAR l l System of tubes that run lengthwise throughout the stem of a plant and connect the roots to the leaves What system in animals does this remind you of?

l l l XYLEM: transports water and dissolved minerals from roots to leaves (ONE WAY!!) Consists of tracheids and vessel elements. Vessel elements are long continuous tubes formed from dead, hollow, cylindrical cells arranged end to end. Tracheids are dead cells that taper at the ends and overlap one another XYLEM IS DEAD!!

l l Pholem transports organic nutrients (sugars) often from the leaves (source) to wherever the sugars are needed (sink). The roots can store excess sugar, but actively growing regions may need the sugar. It just depends. This process is known as TRANSLOCATION

How does phloem work?

MERISTEMATIC TISSUE l l l Its kind of like the stem cells for plants Undifferentiated embryonic plant tissue from which all other plant tissues develop These tissues contain cells which are undergoing rapid division – – Apical or intercalary meristems – found along stems or at the base of leaf blades Lateral meristems – increases circumference or girth of stems