PLANT STRUCTURE AND FUNCTION D Jones Plant Cell

PLANT STRUCTURE AND FUNCTION D Jones

Plant Cell Types parenchyma – metabolism – storage – contain plastids that store starch – support with growth sclerenchyma – support without growth – two forms fibers (flax and hemp) sclereids (nutshells) store

Xylem water conducting dead at maturity – tracheids • long, thin, tapered ends – vessel elements • wider, shorter, thin walled, less tapered Phloem food conducting live at maturity – sieve-tube members • Have sieve plates – companion cells

Tissue Systems dermal – epidermis tightly packed cells cover and protect vascular – xylem & phloem transport & support ground – mostly parenchyma photosynthesis, storage & support – collenchyma – sclerenchyma

Plant Systems roots Stems leaves flowers & seeds

Functions of Roots absorb water and nutrients anchor plants conduct water and nutrients store food

Types of Roots fibrous roots – mat of thread-like roots – just below soil surface – found in monocots tap roots – one long root – deep into soil – found in dicots

Root Cross Section Monocot epidermis cortex endodermis xylem pericycle Dicot xylem phloem cortex

Tissue Characteristics & Functions Tissue Characteristics Function Cortex Cellular spaces for aeration Stores starch endodermis Tightly packed produce suberin(creates water barrier called casparian strip Control movement of water into center of root and prevent outward movement

Root hairs give surface area for absorption

Functions of Stems transport materials support storage

Types of Stems Herbaceous – in annuals – green (photosynthesize) – pliable Woody – in perennials – have bark – inflexible

Stem Cross Sections monocot vessel element (xylem) air space phloem dicot phloem xylem

Tissue functions epidermis – produces waxy cuticle of cutin to protect from water loss cortex – ground tissue containing chloroplasts vascular cylinder – xylem, phloem and pith

Woody Stem periderm cork cambium cortex phloem xylem vascular cambium pith

Tissue functions vascular cambium – produces new xylem and phloem periderm (bark or cork)– protects from water loss cork cambium – produces periderm Sapwood – outermost water-conducting xylem Heartwood – innermost supporting xylem

Leaf Functions photosynthesis – food production

Functions of Leaves photosynthesis

Types of Leaves Simple compound – Pinnate – palmate

Leaf Cross Section

Tissue Functions epidermis – covered by waxy cuticle of cutin that limits water loss palisade mesophyll – specialized for photosynthesis – tightly packed spongy mesophyll – air spaces allow gas exchange guard cells – open and close stomata to allow gas exchange and limit water loss vascular bundles – transport of water and food

Stomata Functioning guard cells have thicker cell walls near the stomata when water moves into guard cells they expand open when water moves out the guard cells close

Factors that Affect Stomata temperature – stomata close limiting water loss when the temperature is high CO 2 concentration – stomata open when CO 2 is low allowing photosynthesis day/night – stomata open during the day and close at night

Flowers and Seeds reproduction

Flower structure

Functions of Flower Parts petals – attract birds and insects sepals – protect flower buds stamen – male structures that produce pollen pistil – female structures tha produce ovules

Seeds

Tissue Functions seed coat - protection Endosperm - storage Cotyledon - storage epicotyl – becomes shoot tip hypocotyl – becomes shoot radical – becomes root

Monocot /Dicot Comparison