exam 4: seedless vascular plants- plants and people

family Salviniaceae

-2 genera: Salvinia and Azolla -floating ferns -sporangia in sporocarps -Azolla with tiny crowded bilobed leaves on slender stems -with colonies of a cyanobacterium -Salvinia has larger undivided leaves in whorls of 3

class psilotopsida

-2 orders: Ophioglossales and Psilotales -homosporous -a single leaf is produced each year

fertilization of pines

-4 tiers of cells are produced -the tier farthest from the micropyle forms an embryo and the other cells become suspensor cells -the integument develops into a seed coat

seed

-a case of heterospory that has been modified to form a ovule -a mature ovule containing an embryo

leptosporangium

-advanced -arise from one single superficial cell which divides transversely -inner cell will contribute to the sporangial stalk or remain inactive -outer cell will give rise to a complex stalked sporangium with a globose capsule with a one cell thick wall -below the thick wall is a tapetum (provides nutrients) -the inner mass develops into spore mother cells -most are homosporous

Class Marattiopsida

-ancient -living ones are tropical -6 living genera

progymnosperm

-appeared during the late paleozoic -intermediate between trimerophytes and seed plants -dispersed spores and secondary xylem -bifacial vascular cambium: producing secondary xylem and phloem -have spores not seeds

lycopodiales/lycopodiaceae

-club mosses -genus Lycopodium -sporophyte is a branching rhizome with aerial branches and roots -roots and stems are protostele -microphylls are spirally arranges -homosporic -sporangia single on fertile microphylls called sporophylls which are interspersed with vegetative microphylls or grouped into terminal strobili or comes -gametphytes are bisexual and mycorrhizal -archegonia and antheridia take years to form -biflagellated sperm requires water for fertilization -embryo grows in venter of archegonium -sporophyte remains attached to gametophyte

pines

-conifers with unique leaf arrangements -genus Pinus -first leaves are needlelike and arranged spirally -after a year the leaves are produces in bundles or fascicles -fascicles are short shoots wrapped by small scalelike leaves -a short shoot is a determinate branch, sometimes may produce indeterminate growth -leaves are adapted to grow in xeric conditions

seed scale complex

-consist of the olviferous scales (2 ovules) and a sterile bract -each ovule consists of a megasporangium surrounded by an integument -each megasporangium contains a single megasporocyte that gives rise 2 4 megaspores, only one of which is functional

early vascular plants

-extinct -includes phyla Rhyniophyta, Zosterophyllophyta, nd Trimerophytophyta

phylum monilophyta

-ferns and horsetails -ferns are herbaceous: no secondary growth -4 major lineages

Tmesipteris

-found in australia and new zealand -grows as a epiphyte on tree ferns and other plants -leaves are larger with a single unbranched vein

isoetales/isoetaceae

-genus Isoetes -quill worts -aquatic -sporophyte consists of a corm with quill-like microphylls on upper surface and roots on lower surface -heterosporous -outer megasporophylls and inner microsporophylls -ligule is present -cambium adds secondary tissue to the corm

sellaginellales/selaginellaceaee

-genus Selaginella -spike mosses -mostly tropical in moist places -sporophyte is herbaceous with microphylls -sporophylls in strobili (cone) -ligule -stem and room are protostele -heterosporous with unisexual gametophytes -microgametophytes are endosporic and consist of 1 prothalial cell and the antheridium -megagametophytes are endosporic -sperm are biflagellated -embryo develop in a suspensoe

family Marsileaceae

-grows on damp or wet soil or with the leaves -leaves resemble a four leaf clover -sporocarps are reproductive structures resistant to drought that contain the sori with megasporangia and microsporangia

genus Equisetum

-homosporous -sporangia borne in groups on sporangiophores which are clustered in a strobilus on the apex of aerial stems -spores are provided with elaters, thickened bands from the outer spore wall that help with dispersal -gametophytes are green and free living -usually bisexual -sperm is multiflagellated and requires water

class Equisetopsida

-horsetails -have joined stems -eusporangiate -1 genus: Equisetum -common on moist or damp places on streams or edge of woods -leaves are small and scale like forming whorls around the stem at the nodes -internodes are ribbed with silica deposits -aerial stems arise from underground rhizomes

how does an ovule become a seed

-in modern seed plants the ovule consists of a nuclellus enveloped by one or 2 integuments with a micryple -the nuclellus contains a megagametophyte composed of nutritive tissue and archegonia -after fertilization, the integuments become the seed coat and the seed is formed

phylum coniferophyta

-includes pines, firs, and spruces

megaphylls

-larger, usually associated with siphonoseles and eusteles, with leaf gaps and a branching vein system -evolved by fusion of branch systems

pollination

-occurs in the spring -pollination drops exuded from the micropyle trap pollen grains and carry then to the nucellus -the scales grow together and protect the ovules -pollen grain germinates and forms a pollen tube

megasporangiate cones

-ovulate cones -found on upper branches -larger and complex -the cone scales are modified determinate branch systems known as seed-scale complexes

microsporangirate cones

-pollen producing -found on the lower branches and are small -microsporophylls are spirally arranged, each with 2 microsporangia -a microsporangia contains many microsporocytes that produce haploid microspores that develop into pollen grains

eusporangium

-primitive -parent cells are located at the surface of the tissue and divide periclinally -the outer cell layer will form the wall of the sporangium -the inner layer will form the spore mother cells

microphylls

-small leaves with only one single strand of vascular tissue (no gaps) usually associated with protosteles -evolved as outgrowths or enations

phylum lycopodiophyta

-the lycophytes -2 lineages diverged in devonian period: lycophyte clade and euphyllophyta clade -herbaceous with microphylls -3 orders with 1 family each

pollen tube in cycads and ginkgo

-the microgametophytes produce pollen tubes that grow in the tissue of the nuclellus absorbing nutrients -eventually the pollen tube bursts over the archegonium releasing the multiflagellated swimming sperm cells

as plant life progressed on land ___

-the plant body developed roots, stems, and leaves -the gametophytic generation underwent a progressive reduction in size and became nutritionally dependent upon the sporophyte -seed evolved

Class Polypodiopsida

-water ferns -most familiar ferns -rhizomes are siphonostele -leaves/fronds are megaphylls -lamina an be simple or divided into leaflets or pinnae attached to the rachis -sporangia occur in clusters (sori) -circinate venation -have indusia -bisexual gametophytes -water required for fertilization -embryo receives nutrients from gametophyte through a foot -sporophyte is perennial while gametophyte is short lived

Psilotum

-whisk germ -tropical and resemble rhyniophytes -sporophyte is dichotomously branched with scale like structures -gametophytes are bisexual, rhizome like, and mycorrhizal -sperm is multiflagellated and requires water for fertilization -sporophytes are initially attached with a foot to the gametophyte

order and families of Class polyposiopsida

1 order: Salviniales 2 families: Marsileaceae and Salviniaceae

4 major lineages (classes) of phylum monilophyta

1. Psilotopsida 2. Marattiopsida 3. Polyposiopsida 4. Equisetopsida

5 phyla of living seed plants

1. cycadpphyta 2. ginkgophyta 3. coniferophyta 4. gnetophyta 5. anthophyta

3 orders/families of lycophytes

1. lycopodiales/lycopodiaceae 2. selaginellales/selaginellaceae 3. isoetales/isoetaceae

events leading to the evolution of an ovule

1. retention of the megaspores within the megasporangium which is fleshy and called the nucellus 2. reduction of the number of megaspores mother cells in each megasporangium to one 3. survival of only one of the four megaspores 4. formation of a megagametophyte inside the single functional megaspore (endosporic) 5. development of the embryo within the gametophyte 6. formation of an integument that completely envelopes the megasporangium, except for an opening or micropyle 7. modification of the apex of the megasporangium to receive microspores or pollen grains

leaf of Psilotopsida

2 parts: a vegetative portion or blade and a fertile segment

4 cells in each pollen grain

2 prothallial cells, 1 generative cell, and 1 tube cell

order ophioglossales

4 genera but only Botrychium (grape ferns) and Ophioglossum (adder's tongues) are found in UA

origin of embryophytes

Chara- or Coleochaete-like green algae

phyla of ferns and fern allies

Lycopodiophyte and Pteridophyta

genera of order psilotales

Psilotum and Tmesipteris

siphonostele

a central pith surrounded by vascular tissues, the phloem may be outside or on both sides of the xylem; with leaf traces and leaf gaps

life cycle of embryophytes

alternation of heteromorphic generations

a seed consists of ___

an embryo, stored food, and a seed coat

when were flowering plants dominant

appeared 125 mya and dominant ever since

when were seed plants dominant

arose at the end of devonian (380 mya). gymnosperms dominated from the mesozoic to about 100 mya

microsporangia and megasporangia in pines

borne in separate cones or strobili on the same tree

when were monilophytes, lycophytes, and proymnosperms dominant

complex group, dominant from devonian to carboniferous (375-290 mya)

most numerous, widespread, and ecologically important gymnosperms

coniferophyta

immature ovule

consists of a megasporangium surrounded by one or two additional layers of tissue, the integuments

zosterophyllophyta

dichotomously branched, stem only, homosporous and heterosporous, protostele, lateral sporangia. related to lycophytes

rhyniophyta

dichotomously branched, stems only, with terminal sporangia, homorsporous, protostele, ancestors of trimerophytes

2 kinds of sporangia in ferns

eusporangium and leptosporangium

____ resolved the problem of water and food transport

evolution of xylem and phloem

seedless vascular plants

ferns and fern allies

vascular plants

ferns, gymnosperms, angiosperms

haploid gametophytic generation in the seed

food reserve

megaspore

forms female gametophyte (megagametophyte)

microspore

forms male gametophyte (microgametophyte)

bryophyte gametophyte vs sporophyte

gametophyte is larger and free-living, sporophyte permanently attached to and nutritionally dependent from the gametophyte

all seed plants are ____

heterosporous

most vascular plants are (homosporous/heterosporous)

heterosporous

euphyllophyta clade

includes all other living vascular plant lineages (ferns, fern allies, and seed plants)

lycophyte clade

includes the modern lycophyte lineage

what happens to the generative cell after pollination

is forms 2 cells: a sterile cell and a spermatogenous cell. the spermatogenous cell will divide, forming 2 sperm

trimerophytophyta

larger, complex branching, only stems, homosporous, protostele, terminal sporangia. ancestors of ferns and progymnosperms

polyembryony

megagametophytes produce several archegonia thus several embryos may develop within a single ovule

megasporangia are borne on ____

megasporophylls

2 types of leaves

microphylls and megaphylls

microsporangia are borne on ____

microsporophylls

bryophytes

mosses, liverworts, hornworts

gymnosperm means

naked seed

is water required for fertilization with gymnosperms

no

do all ferns have sporophytes

no, in some ferns the gametophytes reproduce asexually by gemmae and sporophytes are never formed

in gymnosperms, the microgametophytes develop as ____

pollen grains

protostele

primitive, no pith, usually the phloem surrounds the xylem

heterosporous plant

produce 2 types of spores: microspores and megaspores with endosporic development

homosporous plant

produce only one kind of spore, which will form a bisexual gametophyte with exosporic development (outside the spore wall)

seed coat

protects the embryo and the food storage, critical for germination and establishment of the new plant on an inhospitable land

vascular cylinders or stele classification

protostele, siphonostele, or eustele

classes ____ and ____ are eusporangiate ferms

psilotopsida and marattiopsida

tallest vascular plant

redwood Sequoia sempervirens from CA (a conifer)

ligule

scarelike outgrowth near the base of the upper surface of the microphyll and sporophyll

suspensor

serves to thrust the developing embryo deep within the nutrient rich tissue of the female gametophyte

when were early vascular plants dominant

small size and simple morphologies, dominant during the Silurian to Devonian (425-370 mya). 3 phyla: rhynophytes, zosterophyllophytes, and trimerophytes

over evolutionary time, the gametophytes of vascular plants have become ___

smaller and simpler

indusia

specialized outgrowths of the leaf covering the sori

vascular plant gametophyte vs. sporophyte

sporophytes are larger than gametophytes and free living

what happens 15 months after pollination

the archegonia are formed and the pollen tube reaches the egg cell (fertilization)

embryophytes

the bryophytes and vascular plants, both of which produce embryos; a synonym for plants

what happens after pollenation

the endosporic microgametophyte produces a tubular outgrowth, the pollen tube

what happens 6 months after pollination

the megaspore starts forming the megagametophyte

lycophytes are characterized by____

the presence of microphylls

diploid sporophytic generations in the seed

the seed coat and embryo

pollen tube in conifers and gnetophytes

the sperm are nonmotile and the pollen tubes convey the sperm directly to the archegonia

how are pine leaves adapted to grow in xeric conditions

thick cuticle, thick hypodermis stomata sunk, mesophyll with wall ridges projected into the cells, resin ducts, 1-2 vascular bundles surrounded with transfusion tissue, endodermis

how is the gymnosperm pollen grain transferred

wind (pollination)

eustele

with a vascular cylinder consisting of a system of discrete strands around a pith

circinate venation

young leaves are coiled or circinate