Plant Structure and Growth

Plant Tissue Systems Dermal Tissue – outer covering of a plant Vascular Tissue – Special conducting tissue; XYLEM and PHLOEM Ground Tissue – Makes up the inside of a plant; NOT xylem and phloem

Dermal Tissue Outside of the plant = “epidermis” Cuticle – waxy coat on epidermal cells Cork – Dead cells!

Xylem Vascular tissue in plants; provides support and conducts WATER!

Phloem Vascular plant tissue that moves NUTRIENTS in any direction depending on the plant’s needs.

Roots, Stems, and Leaves

Roots Helps anchor the plant into the ground! Fibrous roots – (monocots) highly branched = grasses Taproots – (dicots) Large central root = radish

Non-Woody Stems Herbaceous – stems that are flexible & green Vascular bundles – bundles of xylem & phloem Monocot = scattered Dicot = arranged in a ring PITH: ground tissue inside the ring of vascular bundles CORTEX: ground tissue outside the ring of vascular bundles

Woody Stems Stiff and non-green Xylem – makes up the inside; major component of wood Phloem – “living”; outside xylem Heartwood – old wood in center of tree trunk Sapwood – conducts water and sap; outside of the heartwood

Leaves Photosynthetic organ Blade – flattened portion Petiole – Stalk that attaches a leaf to the stem

Mesophyll – ground tissue Leaf Tissue Layers

Specialized Leaves Water Lily Leaves – float on water Cactus – modified as spines Tendrils – specialized for climbing Venus’ flytrap – catch insects

Plant Growth and Development

Plant Embryo Plant embryo = embryonic root & embryonic shoot *REMEMBER* A seed develops from an ovule & contains a plant embryo Plant Embryo Plant embryo = embryonic root & embryonic shoot Cotyledons = seed leaves MONOCOTS – one cotyledon DICOTS – two cotyledons

Germination Dormancy – state of suspended animation Germination – Beginning of growth after being dormant

Germination

Breaking dormancy Seeds sprout in response to the environment Must be exposed to cold Seed coats must be damaged Fire Oxygen & Water penetrate

Meristems Meristem: a region of plant cells that divide & can develop into specialized tissues Primary growth: Growth that increases the length or height of a plant. Secondary growth: Growth that increases the width of stems and roots

Primary Growth Apical meristems: growing region at the tips of stems & roots in plants

Secondary Growth Lateral meristems: Responsible for increases in the width.