1. Review What are the three main tissue systems of plants

2. Compare and Contrast How do the three main functions of a plant’s tissue differ

3. Form and Function How might the presence of meristems explain the ability of plants to regenerate from cuttings

4. Infer With your prior knowledge of the circulatory system, write a paragraph comparing and contrasting the structure and function of the vascular system of a plant to the human circulatory system

CH 23 PLANT STRUCTURE AND FUNCTION23.1 Specialized Tissues in Plants

Seed Plant Structure Three principal organs

of seed plants are roots, stems, and leaves.

Roots Anchor plant in ground

Help prevent erosion Absorb water and

nutrients and transport to rest of plant

Store food Hold plant upright.

Stems Support system for the

plant body Transport system that

carries nutrients Defensive system to

protect against predators and disease

Produces leaves and flowers.

Leaves Main photosynthetic

organs Regulates water by

controlling air exchange.

Plant Tissue Systems

Three main tissue systems: Dermal Vascular Ground.

Dermal Tissue

Protective outer covering of a plant Epidermis

Single layer of cells that makes up the dermal tissue May have tiny hair like projections on leaves and

roots.

Vascular Tissue

Supports the plant body Transports water and

nutrients Xylem Phloem Consist of long, slender cells

that connect almost like sections of pipe.

Xylem

Tracheids Xylem cells Leave cell walls made of

lignin when they die Openings allow water

movement from cell to cell.

Xylem

Vessel elements Wider than tracheids

and are arranged end After cell dies, cell walls

allow water to move freely.

Phloem

Alive at maturity Transports sugar throughout plant Sieve tube elements

Arranged end to end with ends having many small holes

Lose nuclei and organelles as they mature

Kept alive by companion cells.

Phloem

Companion cells Supports sieve tube element.

Ground Tissue

Produces and stores sugars Contributes to physical support of plant Neither dermal nor vascular Three types of ground tissue:

Parenchyma Collenchyma Sclerenchyma.

Parenchyma

Main type of ground tissue Have thin cell walls Contain many chloroplasts in leaves.

Collenchyma

Strong, flexible cell walls that help support plant organs

Middle cell wall thickness.

Sclerenchyma

Extremely thick, rigid cell walls Makes ground tissue such as seed coats tough and

strong.

Meristems

Regions of unspecialized cells in which mitosis produces new cells

Found in tips of stems and roots.

Apical Meristems

Meristem at tip of a stem or root

Cells divide rapidly Increases plants length.

Floral Meristems

Produces flowers specialized cells Develop from apical meristem.