Kingdom Plantae Autotrophs (photosynthesis) Eukaryotic Multicellular By Diana L. Duckworth Rustburg High School, Campbell County

Plants were first life to invade land some 400 million years ago Three major problems to solve: (1) How to get nutrients out of bare rock –Partnership with fungi - mycorrhizae (2) How to keep from drying out –Developed watertight covering – cuticle –Also kept out gases – developed stomata (singular – stoma) (3) How to reproduce without water medium –Sperm enclosed in pollen – wind or insect dispersal; prevents drying out

cuticle Stomata

Demands of land environment led to cell differentiation & thus different tissues and enabled larger sized plants Stems – provide support; contain vascular tissue to carry nutrients & water to leaves from roots Roots – anchor plant in soil; take up nutrients and water Vascular tissue –Xylem – carries water & minerals from roots –Phloem – carries food made in leaves by photosynthesis to rest of plant Seeds – multicellular; contain embryo of plant –Protection – seed coat prevents injury & dessication of embryo –Nourishment – food for plant embryo as it starts to grow –Dispersal – by animals or wind or water –Delayed growth – can remain dormant until conditions are right to germinate Leaves – structures specialized to carryout photosynthesis Flowers – specialized structures to make reproduction more efficient

Kinds of Plants - Nonvascular Small – no specialized structures for taking up nutrients or water; each cell for itself Gametophyte generation is larger & photosynthetic; sporophyte non photosynthetic & grows on gametophyte Need water for sexual reproduction – sperm swim to eggs

Nonvascular Examples Mosses – leaves arranged in spiral around stem –Have cuticle, stomata, water conducting cells Liverworts – lack conducting cells, cuticle & stomata Hornworts – lack conducting cells, cuticle, stomata

Seedless Vascular Plants Have a vascular system Sporophyte is larger & photosynthetic Do need water to reproduce Have drought- resistant spores Example: Ferns

Gymnosperms – naked seed Produces seeds not enclosed in fruit Gametophytes are male & female; greatly reduced –Male are grains of pollen –Female form within structures that become seeds –Have male & female cones Wind pollination Example - conifers

Angiosperms – Flowering Plants Male & Female gametophytes develop within a flower – promotes pollination Seeds are enclosed in a fruit – promotes dispersal Seeds contain supply of food called endosperm

Two kinds of angiosperms: monocots & dicots Monocots –One seed leaf –Flowers have parts in multiples of 3 –Long narrow leaves with parallel veins –Examples – grass; corn; lilies

Dicots –Two seed leaves –Flower parts in multiples of 2, 4, 5 –Leaves with branching veins –Examples: roses –Daisies; fruits such as apples, peaches, etc.

Comparison of Monocots & Dicots