Lec: CH. 35 Plant Structure

Root system

• roots rely on sugar to produced by photosynthesis

• bottom half of flowering plant

functions

• anchoring the plant

• absorbing mineral and water

• storing organic nutrients

shoot system

• rely on water and mineral absorbed

• top half of flowering plant

Taproot system

• one main vertical root that gives arise to large lateral roots

Root hairs

• absorption of water and mineral

• increase the surface area

leaves = the main photosynthetic organ

• consist a plattened blade and a stalk petiole, joins the leaf to a node of the stem

• monocots have parallel vines

• dicots have branching viens

evolved modified leaves

• tendrils - cling

• spines - prickly

• storage leaves

• reproductive leaves

• bracts- look like petals, attract pollinators

Vascular Tissue system

• carries out long distance transport of materials between roots and shoots

• dermal

• vascular

• ground tissue

Ground tissue system

• cells specialized for storage, photosynthesis, and support

Parenchyma

ground: thin flexible cell walls = photosynthesis, storage

Collenchyma

ground: thicker cell walls for flexible support

Sclerenchyma

ground: thick secondary cell walls reinforced with lignin for rigid, strudy support

two type of water conducting cells of the Xylem

1. Tracheids: are found in the xylem of all vascular plants

2. Vessel elements: are common to most angiosperms and a few gymnosperms

Sugar conducting cells of the Phloem

• Sieve-tube elements, plates are the porous end walls that allow fluid to flow between cells along the sieve tube

Indeterminate growth

a plant can grow throughout its life

Determinate growth

some plant organs cease to grow at a certain size

Annuals

complete their life cycle in a year or less

Biennials

require two growing seasons

Perennials

live for many years

Meristems

• are growth regions,

• have perpetual embryonic tissue that allows for indeterminate growth

• embryonic and stem cell growth

Apical meristems

• located at the tip of roots

• located at the axillary bud of shoots

• young tissue for reproduction

Lateral meristems

• add thickness to woody plants

• secondary growth

• grow to the side, change diversion

Tissue orgainization of leaves

• stoma- epidermis in leaves, allows CO2 exchange (mouth of plant)

• guard cells- regualte its opening and closing, each stomatal pore is flanked by two guard cells (water intake)