Plant Anatomy Systems and Tissues

Plant Structure Root and shoot systems are made up of basic plant organs: roots, leaves, stems, flowers.

Root system What are the major functions of roots? Anchor plant Absorb water and minerals Store sugar as starch Transport materials Produce some hormones Interact with soil microbes

Shoot system functions What are some of the major functions performed by the shoot system? Photosynthesis (primarily in leaves) Transport of materials Reproduction Hormone synthesis

Structure is used in classification Two main categories of flowering plants: monocots and dicots The two groups are distinguished on the basis of flower parts, leaf veins, and other structural features.

Flowers Monocots: flower parts in 3’s Dicots: flower parts in 4’s, 5’s, 6’s

Leaves Monocots: parallel veins in leaves Dicots: network of veins in the leaves

Roots Monocots: fibrous root system with no main tap root. Dicots: Main tap root, with smaller side roots branching off.

Seeds Monocots: single cotyledon; endosperm and cotyledon are separate Dicots: two cotyledons; endosperm is contained in the cotyledon.

This flower is probably a: Monocot Dicot

This flower is probably a: Monocot Dicot

This flower is probably a: Monocot Dicot

W O R K T G E H If you’re asked to distinguish between monocots and dicots, which plant parts would make this task easiest?

Plant Tissues Dermal tissue Ground tissue Vascular tissue

Copy this table: Primary tissue type Sub-types Structure Functions Dermal Epidermis Periderm Ground Parenchyma Collenchyma Sclerenchyma Vascular Xylem Phloem

Dermal tissue: Epidermis How is an epidermis of a plant similar to your epidermis? What does the epidermis do? What features do you see in these cells? Covers flowers, seeds, fruit Secretes a waxy substance called cuticle as waterproofing. May produce special structures such as hairs.

Dermal tissue: Periderm How is the periderm like the layer of dead skin cells on human skin? What does the periderm do? What features do you see in these cells? Replaces epidermis on roots and stems of woody plants with age. Composed mainly of thick, waterproof cork cells. Protects stems and roots.

Ground tissue: Parenchyma What can you see in these parenchyma cells? What are some functions of parenchyma cells? Thin-walled cells Alive at maturity Many functions, including photosynthesis, starch storage, hormone production.

Ground Tissue: Collenchyma How might support cells be different from other plant cells? Plants don’t have a skeletal system as humans do. What holds a plant up? What features do you see in these cells? Flexible support tissue. Elongated cells with irregular shapes and unevenly thickened walls. Living at maturity.

Ground tissue: Sclerenchyma How are these thick-walled cells different from collenchyma cells? What features do you see in these cells? Sclerenchyma cells are dead at maturity. Why might that be? Support tissue. Elongated cells with thick cell walls. Dead at maturity. Forms long fibers, or smaller sclerids (such as stone cells in pears).

Vascular tissue: Xylem Xylem tissue moves water. What features would the cells need to carry out this function? What features do you see in these cells? Long, tube-like cells, joined end-to end, that transport water and minerals from soil to leaves. Two types of cells: tracheids (in conifers) and vessel elements (in flowering plants).

Vascular tissue: Phloem Phloem tissue moves sap, which is sugar dissolved in water. What features would the cells need to carry out this function? What features do you see in these cells? Tissue that transports dissolved sugars (sap) in a plant. Two types of cells: Sieve tubes (alive but no nucleus) Companion cells

Wood contains cells that are dead at maturity. They must be: Phloem Xylem Parenchyma Collenchyma

Potatoes are tubers (modified stems) that store starch Potatoes are tubers (modified stems) that store starch. Most of a potato’s tissue must be: Sclerenchyma Collenchyma Parenchyma Vascular tissue

W O R K T G E H Linen thread for weaving fabric is spun from bast fibers that come from the stem of the flax plant. Bast fibers are long, tough, and strong. Which plant tissue type are they most likely made up of?