ESF Diversity of plants lab practical 2
bryidae life cycle
*has meiospores, sperm has two flagella
2 strongest synapomorphies for lycopsid clade
*stalked kidney bean shaped sporangia* clearly united to one another and fossil kin by this character, allows for phylogenetic resolution in lycopsid lineages
vascular plants characters
- conspicuous and long lived plant body - sporophyte - vasc system of x and p - presence of multicellular archegonia
selaginella life cycle; how is it different?
- very differential embryo; shoot and root apical meristem multicellular * endosporic *gametophyte tissue food for developing embryo, like seed plants*
sporophyte of selaginellaceae
-conspicuous megasporophylls > strobili > megasporangia > megaspores (large, few, yellow) micro for male (red, many small spores)
economic importance of lycopodium
-homeopathic remedies for memory, ear aches, sore throats, digestive disorders, ut problems, blood vessles, bones, joints liver and heart. -pyrotechnics/photography -floral industry -lubricant
lycopodiophyta characters and classes
-homosporous and heterosporous -microphylls -motile sperm -low growing, herbaceous, usually understory/epiphytic plants -common in wet tropics, also canopy dwellers lycopodium, selaginella and isoetes
Family selaginaellaceae
-only has a single genus, 750 sp growing in tropics -all sp are HETEROSPOROUS either develop into microgametophyte or megagametophyte
leptosporangiate (define, which pteridophytes)
-sporangium arises from a *single initial cell* and whose wall is composed of a single layer of cells, capable of spore discharge -stalked sporangium w/ annulus -active spore dispersal -circinate venation POLYOPSIDA & SALVINALES
eusporangiate (define, which pteridophytes)
-sporangium that comes from *several initial cells*, forms a wall of more than one cell layer thick -passive spore discharge -no circinate venation -no stalk PSILOTOPSIDA, MARATTIOPSIDA, EQUISETOPSIDA
microphylls
1 strand of vascular tissue
Marchantia gametophyte cross section
1- parenchyma cells 2-rhizoids (1 cell layer) 3- pores 4-chloroplasts 5(not there but under 3)- epidermis
polypodiopsida habitats and how many
12,000 sp, 320 genera, 35 families diverse in tropics, many in temperate forests, arid habitats. many diversified after conifer and angiosperm radiations.
3 classes of bryophytes
:bryidae, sphagnidae, andreae
ground cedar
L. tristachyum
multicellular sex organs of marchantia
PRODUCED ON SEPARATE 'MALE' AND 'FEMALE' PLANTS antheridia - antheridial disks evelated on antheridiophore a few mm above thallus. In presence of water, produce many motile sperms surrounded by sterile protective cells and are embedded in the upper surface of the antheridial disk. Antheridia rupture and reach archegonium through water. archegonia - archegonial disk on archegoniophore pendant at maturity
2 species of selaginella have also been collected from onondaga county. Seligenella apoda is usually found in wet places whereas S. rupestris is from relatively dry areas. What morphological criteria can you use to differentiate these 2 sp?
S. rupestris - dense, fluffier looking, likely retains more h2o when wet like a sponge S. apoda - smaller, daintier, doesn't need to hold water constantly.
homosporous
all spores produced are same bisexual gametophytes self fertilization potential monoicous
primary function of root system by ancient lycopods
anchoring
isoetes is nearest living relative to
ancient tree lycophytes of the carboniferous (lepidodendrales), sharing the feature of secondary xylem, vasc cambium secondary xylem may have evolved multiple times through convergent evolution
when did arborescent 40 m tall lycophytes dominate and why did they go extinct
carboniferous; coexisted with small herbaceous lycophytes. became extinct at beginning of permian when the climate cooled
describe at least one technique used by paleobotanists to study fossil plants and the kind of info that can be obtained from it
cellulose acetate peel replicas of etched surfaces embedded in sheets of cellulose acetate; replicas so detailed that the microstructures of plants can be easily studied under a light microscope.
protostele and three types
central core of vascular tissue, cylindrical strand of xylem, surrounded by a region of phloem. might have been an endodermis that regulated the flow of water into and out of the vascular system haplostele, actinostele, plectostele
Lycopodiaceae
club mosses -small, simple, microphyllous (only 1 vasc strand, no leaf gap) leaves irregularly or spirally arranged in vertical rows -sporangia borne in sporophylls, axils of fertile leaves -sporophylls commonly reduced and grouped in terminal cones strobili
mnium capsule longitudinal section; where is the columella and what does it contain?
columella long central column of sterile cells
habitat of lepidodendron?
dense stands in wet areas of prehistoric coal swamps
most significant factor for vp evolution
development of vasc system for effective translocation of waters, minerals and sugars to all parts of plant body
heterosporous
different spores m and f spore give rise to m and f gametes unisexual less chance for selfing dioicous
major difference in n/2n generations between mosses and 'higher' plants
dominant sporophyte, gametophyte dependent or free living
lycophytes and pteridophytes arrived
during the late devonian to the mid-silurian ~ 375-290 mya
exospory vs endospory
exospory: gametophyte develops outside of spore wall endospory: gametophyte develops begin developing within spore wall
label parts of polytrichum
foot - attaches sporophyte to the gametophyte plants seta - stalk capsule - spore producing strucutre calyptra - (covering for the head) is gametophytic tissue derived from the wall of the archegonium in which the sporophyte developed operculum - small lid covering very end of capsule peristome - teeth holding sentral disk (annulus) in place
sporophyte of marchantia (describe formation)
formed after sperm cells swim to the neck of archegonium and up to egg cell, leading to fertilization and then formation of a zygote. the zygote divides repeadetly within archegonium to form a multicellular sporophyte, the 2n generation, which remains attached to and is nutritonally dependent on the gametophyte
Asexual reproduction in Marchantia can result from
fragmentation of its body OR by dispersal of specialized structures called gemmae found in cups. (two arrows = growing points)
What large alga showed similar dichotomous branching to Marchantia polymorpha
fucus
granite moss: tetraphis pellucida what feature does this have in common with liverworts?
gemmae cup
class andreaeiade
granite mosses alpine or subalpine habitats grow on granite rocks common in high peaks of adirondaks * gametophyte like a moss * capsule more similar to a liverwort
similarity between bryophyte, lycophyte and pteridophyte sperm are reliant on
h2o for successful fertilization
female moss plant
have terminal leaves bent inward to form a slender tip
function of elaters in marchantia sporophyte?
help shoot spores further
lycopodiaceae members all homosporous or heterosporous?
homosporous
phylum anthocerophyta
hornworts **have a reduced protonema -primarily tropical-sub tropical areas -biflagellate sperm, rely on aquatic env -ecological pioneers, grow in areas with little to no competition
which species on display does not have sporangia borne in cones?
huperzia lucidula
conducting cells inside of mosses
hydroids and leptoids
sporophyll
leaf containing gametes
phylls
leaves
moss sporophyte formation describe
like liverworts, fertilization takes place in water. The zygote, the first cell of the sporophyte generation, develops in archegonium and through successive mitotic divisions, leads to the multicellular sporophyte which remains anchored to the archegonial gametophore during its short life
phylum marchantiophyta (characters and common name)
liverworts; has a plant body that is dorsoventrally orientational, thallus like or leafy and usually prostrate
lycopodium clavatum
locate: root, underground stem, upright stem, microphylls and strobilus
Asteroxylon - extinct group of herbacous lycopods, what extant lycophyte was it compared to and what features were used in comparison
lycopodium - xylem (actinostele) star shaped
cross section of selaginella under microscope. find xylem and phloem how different is the anatomy of this plant from lycopodium?
lycopodium stele is a plectostele selaginella stele is a polystele/distellic (each stele is a protostele with xylem core surrounded by phloem with pericycle and epidermis)
Bryophytes (phyla and characters)
marchantiophyta, bryophyta, anthoceraphyta. -presence of motile sperms and dependence on h2o for successful fertilization -heteromorphic alternation of generation between conspiciuous nutritionally independent gametophyte (n) and small dependent sporophyte (2n) -lack vascular tissues -multicellular sex organs and multicellular embryos
moss costa
midrib of specialized cells that runs lengthwise of the "leaf"
specimen cross sections of ventral antheridia and archegonium we observed on slides
mnium
compare stem and leaf of lycopodium with stem-like and leaf like structures of moss mnium. how are they different?
mnium - no lignin, has hydroids and leptoid cells to conduct h2o lycopodium - has vascular tissue and therefore lignin
compare moss and lycopodium life cycles (ploidy levels, sporophyte gametophyte phases)
moss: dominant haploid gametophyte lycopodium: dominant diploid sporophyte, homosporous
Phylum bryophyta characters
mosses -erect stem-like structure bearing thin expanded sheets of cells that function like leaves. -rhizoids = anchorage -gametes protected until maturity by steril jacket cells (same as marchantia) -sporophyte produces sporangium in which numerous spore mother cells undergo meiosis to produce haploid spores
in what ways does moss photosynthesizing organs differ from a true leaf
no possession of lignin = no vascular tissue (true leaves have lignin therefore vt)
lepidodendron typical leaf scars
note features
hornwort life cycle
note protonema
herbarium mounts of lycopodium
note tiny oil rich spores are borne in spore cases or sporangia which are usually clustered into cones or strobili
why does hornwort sporophyte stay attached to parent?
nutritionally dependent on gametophyte
function of peristome
permit spore dispersal only in dry weather
explain what spines on sawdonia are and their possible evolutinary significance
photosynthesis, early leaves?
mature marchantia sporophyte diagram
placenta- ontop of foot foot- anchors structure in gametophyte tissues seta- short stalk capsule- terminal oval spores- red/green dots elaters- green and long
Pteridophyta
polyopsida, marattiopsida, psilotopsida, equisetopsida
which pteridophytes are homosporic?
polyopsida, marattiopsida, psilotopsida, equisetopsida
which pteridophytes are exosporic?
polyopsida, salvinales, marattiopsida, psilotopsida, equisetopsida
hair-cap moss examined in lab
polytrichum
comparing cooksonia and sawdonia to modern plants, what was the major indicator of the earlier plants' simplicity?
primitive vasc tissue
which part of marchantia life cycle is most vulnerable to environmental stress
protonema - looks like algae, acts like it no cuticle, wouln't last long w/o moisture
cross section of lycopodium stem; can you find any vascular tissue in the cortex of the stem? what does the presence of this structure indicate?
protostele plectostele -- vt = potential areas where microphylls would be connected to stem
Isoetaceae
quillworts, one genus 150 sp all HETEROSPOROUS -plant body relatively small with a greatly shortened axis and has tufts of leaves and roots -secondary xylem -grass-like -found in lakes, ponds, swampy areas and ephemeral pools
microsporophyll color
red
stigmaria
root of ancient lycopod trees composed of sandstone preserved due to sand and mud getting into caveties of trunk following death
which pteridophytes are heterosporic?
salvinales (shares this with isoetes and selaginella likely by convergent evolution)
early vps (name them) characterized by
small stature simple & primitive morphology rhyniophyta, zosterophyllophyta and trimerophyta dominant from mid silurian to mid devonian ~410-370 mya
spores of lycopodium give rise to
small subterranean gametophytes bearing both archegonia and antheridia
what does protonema closely resemble and how can you distinguish it?
soil inhabiting algae -- protonema has buds, disk like chloroplasts and has slanted cross walls while algae have perpendicular cross walls
note differences in foliar morphology based on a few reps
some are more smooth looking (like a single stem) others are leafy all over. some just leafy on tips
what part of the cycle indicates aquatic ancestry and explain
sperm - needs h20 to move and swim to egg to effectively fertilize protonema - needs h20
pteridophyte sperm?
still need water for movement, now have multiflagellate sperm so that plant may survive further from water.
lepidostrobus: what is it and when would it reproduce?
strobilus of lepidodendron individuals would reproduce once at end of its lifetime by way of encapsulated spores
male moss plant
terminal rosette of leaves in which the long, slender, stalked antheridia are embedded
why are hornworts less successful in moderate to dry environments?
the archegonium and antheridium are not close to eachother in 'pores' of the thallus so water allows them to open and sperm can move to archegonia
what could be a reason for a horn shaped sporophyte?
to get higher up so spores will be dispersed further and more effectively
class bryidae - what are the two distinct phases of the gametophyte?
true moses 1. protonema - when a spore germinates cell divides repeatedly to form an extensive branched filamentous body which gives rise to the... 2. gametophore which will develop into an upright moss plant
antheridial disk cross section: where are antheridia located on disk (upper/lower surface) and what is the significance of such a location?
upper surface for splash transport of sperm to archegonium
archegonial disk cross section: what is the swollen basal portion where archegonium are located called?
venter
where on the underside of Marchantia thallus are the rhizoids attached
ventral side of thallus, not present on central line of ventral side
class sphagnidae economic importance and why
water retaining capacity - large dead cells with secondary thickening absorb and hold large quantities of water used to lighten heavy soils and improve water holding capacity of light sandy soils.
megaphylls
webbed vascular strands
what does presence of root system in ancient lycopods indicate about the nature of substrate during devonian period?
wet/ floating forests
what is sphagnum water holding capacity (ratio) and how
wet:dry weight 1:10 due to LARGE EMPTY CELLS in addition TO SMALLER PHOTOSYNTHESIZING CELLS in mature leaf-like structures green cells = living large clear cells = dead
psilotopsida
whisk ferns order psilotales psilotum (L) and tmesipteris (r) -lack true roots and true leaves. -upward growing stems green and psynthetic. -rhizomes or lateral stems -ephiphytic * because they lack leaves they were og though to have been modern descendents of early vps like rhinyophytes, molec evidence proves they are more closely related to ferns *ophioglossales (grape ferns, once under polypodiopsida) being considered for psilotopsida
megasporophyll color
yellow