Plant Biology DAT

Seed coat

hard outer layer

endosperm

storage providing nutrients

embryo

early plant develops within the seed

radicle: first part to emerge out of seed, develops into roots

hypocotyl: bottom region of young root

plumule: develops into leaves

epicotyl: top region shoot tip

meristems

regions on plant composed of growth cells

primary growth

vertical growth, occur at apical meristem, occurs before secondary growth

secondary growth

horizontal growth, occurs at lateral meristems, woody plants

vascular cambium

ring of meristematic tissue located between primary xylem and phloem

primary xylem: transport water and minerals from root to shoot/leaves

primary phloem: transport nutrients from leaves to root

secondary xylem: inside ring, form outside wood

secondary phloem: outside ring, form inner bark

Cork Cambium

ring of meristematic tissue outside the phloem

outermost protective layer, dead bark cells

ground tissue

structural support, most plants mass

all non-vascular and non-dermal tissue

vascular tissue

transport water and nutrients

phloem

transport sugars from leaves to root

sieve cells: elongated organelle lacking cells that connect to form continuous channels for nutrient transport

companion cells: organelle-containing cells that connect to sieve cells to support metabolic processes

xylem

transport water and minerals from roots to leaves

tracheids: long, thin cells that transport water through pits in their tapered ends

vessel elements: short, stout cells that transport water through cell perforations

dermal tissue

outer layer, protection and regulation

waxy cuticle. limits water evaporation

Casparian strip

impenetrable substance in cell wall of root endodermis, made of fats and waxes

Water doesn’t pass through cells until it passes the strip

water forced out of cell wall and into endodermal cell cytoplasm