Chapter 25 Seedless Plants

Aquatic Plants

all plants have descended from them, easy survival-gametes transferred through water

Sporopollenin

protects spores/pollen from desiccation

Alternation of generations life cycle

two life stages in the same individual-sporophyte and gametophyte

Sporophyte

stage that produces spores

Gametophyte

stage that produces gametes

Apical meristem in roots and stem

allows vertical growth

Waxy cuticles on leaves and stem

prevents desiccation

Lignin in vascular tissues

structural support

Sporopollenin

is an organic molecule that are similar to fatty acids and catenoids, thick cell walls made of it

In humans

diploid stage=multicellular, haploid stage=unicellular gametes

In plants

diploid and haploid stage are both multicellular

Alteration of Generations

describes the life cycle of organisms that have multicellular diploid and haploid stages

Desiccation

the drying out of an organism by the removal of water

The Haploid gametophyte stage in seedless plants

produces haploid gametes through mitosis, creates new individual plants-diploid sporophyte 

The diploid sporophyte stage

produces haploid spores through meiosis, spores germinate into new gametophyte plants

Seedless Plants

Sporophyte is the diploid stage

Sporophyte is the result of

Gamete fusion(fertilization)

Nonvascular seedless plants

sporophyte stage is dependent in the gametophyte stage

Sporangia

sporophyte produces

Sporocysts

cells that make up sporangium structure which produce haploid spores through meiosis

Homospores

sporophytes that produce only one type of spore

Monoecious gametophyte

both male and female are on the same plant

Heterosporous

sporophytes that produce two different types of spores called heterospores

Microspores

male spores

Megaspores

female spores

In seedless plants

gametophyte is the haploid life stage that produces gametes through mitosis

Gametangia

structures that produce haploid gametes through mitosis 

Antheridium

male gametangium, produces sperms

Archegonium

female gametangium, produces eggs

Meristem tissue

is comprised of undifferentiated cells can develop into any type of cell

Apical meristems

are located in the shoot tip and the root tip of plants, allows vertical growth

Waxy cuticle

epidermal tissue that contains wax

Nonvascular Seedless Plants

called Bryophytes, extant species that are most similar to earliest terrestrial plants

Nonvascular Definition

no conductive tissue to transport water and products of photosynthesis

Nonvascular Seedless Plants

Dominant Gametophyte (n) stage and Sporophyte (2n) is dependent

Bryophyte Structure 

nonvascular, no conductive tissues, have thallus and rhizoids- dependent gametophyte stage

Bryophyte life cycle

Gametophyte stage is dominant (haploid), gametangia grows from thallus

Archegonia

eggs via mitosis

Antheridia

sperm via mitosis

Bryophyte

fertilization results in diploid zygote grows inside archegonia (sporophyte stage)-develops sporangia which produces haploid spores through meiosis

Leaves

increased surface area for greater photosynthetic efficiency

Microphylls

spine shaped leaf with single unbranched vascular vein

Megaphylls

larger leaf with branched vascular network

Sporophylls

modified leaves with sporangia

Vascular Seedless Plants

sporophyte (2n) is dominant stage (gametophyte reduced)

Vascular Seedless plants lifecycle

Zygote (sporophyte) grows from parent plant (gametophyte) but is independent and dominant, produces haploid spores via- spores germinate into haploid gametophyte