plants part 2

3 main functions of roots

• take water and dissolved minerals and transport them to where they are needed

• anchor plant in soil, another plant, or object, which supports it against wind and water

• stores carbohydrates produced by photosynthesis, water, and nutrients

root cap

protecting covering of the tip of the root

cortex

layer of cells between epidermis and vascular tissues of the root

apical meristem

produce cells that develop into diff types of root tissues that perform diff functions

epiderimis

single, outer layer of cells

endodermis

layer of cells between cortex and vascular tissue of the root

Casparian strip

waterproof band surrounding each cell in the endodermis

xylem in monocot

form ring arouth pith

xylem in dicot

form X or star shape

phloem monocot

surround xylem cells in ring

phloem dicot

between arms of star (xylem)

pith

core of cells

2 major kinds of root systems

taproot and fibrous roots

taproot

root system made of thick root with a few smaller lateral branching roots

taproot ex

carrot

fibrous root

root system made up of many small branching roots

fibrous root ex

grass roots

aerenchyma

plant tissue with air spaces for gas exchange for gas exchange in aquatic plants

modified root

roots that are modified to provide extra support for a plan or to store food in water

modified root ex

sweet potato modified to store food and water

herbaceous vs woody stem

• soft and flexible vs hard and rigid

• photosynthesize vs old woody stems don’t photosynthesize as much

• live for one growing season vs live in multiple growing seasons

stem function

provide support for plant’s leaves and reproductive structure

blade

external structure of leaf has flat portion with large SA

petiole

how leaf attached to stem

cuticle

waxy layer on epidermis that is secreted by epidermal cells

mesophyll

layer between upper and lower epidermis of a leaf that contains many chloroplasts

palisade mesophyll

layer of cells where most of photosynthesis takes place immediately below epidermis

spongy mesophyll

layer of irregularly shaped, loosely packed cells below palisade meosphyll layer

cuticle function

reduces water loss and evaporation

spongy mesophyll function

contain spaces between cells that allow O2, CO2 and water vapour to move around cells, also contain few chloroplasts

vascular bundles in leaves

located in the veins of the leaf and is made of xylem and phloem

xylem in leaf

carries water and minerals from roots to leaf and is located on upper side of leaf vein

phloem in leafs

carries sugar away from leaf to rest of the plant and located on lower side of leaf vein