Lecture 17. Roots & Leaves

2 main root types

Fibrous roots (monocots) & taproots (eudicots)

Fibrous roots

Mat of thin roots, spread uniformly at shallow depths

Taproots

Large, central, vertical root

Root Apical Meristem (RAM)

At tips of roots - behind protective root cap

Apoplastic pathway

Water moves through porous cells walls

Symplastic pathway

Water moves from cell to cell via plasmodesmata

Apoplast

Extracellular space outside of plant cell membranes

Symplast

Region enclosed by cell membranes within which water + solutes can diffuse freely

Casparian strip

What allows roots to be selective - certain solutes can enter the xylem

Fungal hyphae

What increases surface area of plant roots - mutualistic relationship b/n plant & fungi

Chloroplasts

Concentrated in palisade mesophyll

Spongy mesophyll

Gas exchange occurs in…

Stomata

What open into intercellular air spaces?

Vein

What is the vascular structure of leaf?

Vascular bundle

Vein made up of a…

Evolutionary modification of leaves

Spines, starch or water storage organs, tendrils, traps

Photosynthesis

Consumes CO2 & releases O2

Cellular respiration

Consumes O2 & releases CO2

Lenticels

Opening in bark that allow gas exchange