Lab 8 - Primitive tree -Bryophytes,Ferns and also Fern Allies
As we pass indigenous mosses come ferns, we view a gradual shift fromprimitiveto contemporary traits. There are two major trends girlfriend should focus on intoday"slab. The an initial is a transition in life cycles, the 2nd is a changeinbasic internal structure.
You are watching: Which of the following lacks vascular tissue?
First, all tree undergo one alternation the generations,between a haploid gametophyte stage and also a diploid sporophytestage. In the many primitive plants, like mosses, the gametophyte isdominant(i.e. It"s big and green). In higher plants choose ferns and fern allies,the sporophyte phase is dominant. Gametophytes develop gametes (spermandeggs) in a one-of-a-kind structure referred to as a gametangium (-ia), whilesporophytesproduce spores in a distinct structure dubbed a sporangium(-ia).
Second, all plants require to acquire water to your cells.Primitivebryophyteslike mosses and also liverworts are so tiny that they have the right to rely top top diffusionto move water in and out the the plant. Mosses have actually a few strands ofwaterconducting tissue in their central stem, however nothing prefer the large andwell organized network of pipe in tracheophytes, or "tubeplants".The vascular tissues in the much more advanced ferns and also "fernallies"are made up of xylem and phloem, which command water,nutrients,and food transparent the plant body. We"ll look at at this tissues in alaterlab.
Bryophytes also need a moist setting to reproduce. Theirflagellatedsperm should swim through water to with the egg. Therefore mosses andliverwortsare restricted to moist habitats. There are no mosses in the desert.Butmosses space surprisingly resistant to dry up, and can survive underveryharsh conditions. Mosses space the most abundant plants in both theArcticand the Antarctic. Asexual reproduction in bryophytes is accomplishedbyfragmentation or by small vegetative "sprouts" called gemmae,whichform in special tiny structures called gemmae cups.
Mosses and also liverworts room lumped with each other as bryophytes,plantslacking true vascular tissues, and also sharing a variety of other primitivetraits. They additionally lack true stems, roots, or leaves, though they havecellsthat do these general functions. The leafy green plant that we seewhen us look at a moss or a liverwort is yes, really the gametophyte,which is the leading stage in every bryophytes. The sporophytesofbryophytes do not have a free-living existence. Castle grow straight outof the fertilized egg in the archegonia, and remain dependent on theparentgametophyte for their nutrition.Characteristics the Divisions
Division Bryophyta - (9,500 sp.) - mosses, Mnium, Sphagnum
Mosses come in two basic types, a cushiony type, with erect stalks,and a feathery type, which creates flattened carpet of low-lying and also highlybranched moss plants. In both cases, the leafy environment-friendly gametophytes aredioeciousThey can be male plants, v antheridia in ~ the height of the plant, orfemaleplants, with archegonia in ~ the top. Remember the these gametophytesarealways haploid (1N) plants.
Sperm are produced within each antheridium, and also an egg ineacharchegonium.Because the plant is currently haploid, this gametes have the right to be developed bymitosis,simple cabinet division. The sperm swims come the archegonia through a thinfilm the water, attracted by a chemical attractant produced by the femaleplant,then swims down the neck that the archegonia to the egg. A good morningdewis an ext than adequate water for the sperm come swim. When the spermentersthe archegonia, that fuses with the egg. The 2N zygote develops into adiploidsporophyte plant, a small stalk that grows straight out that the height ofthearchegonium. This stalk is at first green, and photosynthetic, butlaterturns brown and becomes essentially a parasite on the femalegametophyte.
The sporophyte plant is composed of a stalk, and also a small capsuleon the top. In ~ the capsule, cells undergo meiosis come producetetradsof haploid spores. As soon as the capsule is ripe, its hinged lid oroperculumopens up, and the spores are quickly dispersed by wind and also water. Thesporesgerminate into a tiny environment-friendly thread, i beg your pardon looks like a straightforward strand ofgreen algae. This similarity is one more clue that bryophytes aredescendedfrom eco-friendly algae. This beforehand threadlike stage is called the protonema(= very first thread, many = protonemata, prefer stigma/stigmata). The newadultgametophytes thrive from a small bud that creates on the protonema.Eventuallythese gametophytes will flourish to develop gametes, and also the totality cyclewillstart over again. Mosses can also reproduce asexually by fragmentationor through growing small vegetative buds called gemma, which deserve to break offand thrive into a new plant .
While bryophytes in general are much more interesting than important, inthe usual sense, a conspicuous exception are mosses of the genus Sphagnum.Sphagnummoss forms thick mats which become compressed right into peat, which deserve to beusedas fuel, return it’s very smoky. Peat likewise contains other plants suchas reeds, that thrive amid the sphagnum. In dried form, peat moss isremarkablyabsorbent and, and also has been used for diapers, for enriching bad gardensoils, and also as a ar dressing because that wounds. Whereas cotton absorbs 4-6timesits dried weight, dried sphagnum deserve to absorb 20 time its very own weight influids!Peat bogs are really important and interesting ecosystems. Sphagnummosses considerably increase neighborhood acidity by releasing H+ ions, and also the pHof peat bogs have the right to drop to 4 or lower, perhaps the most acidic naturalenvironment.Peat bogs cover about 1% that the Earth’s soil surface, an area abouthalfthe dimension of the joined States.
Division Hepaticophyta - (9,000 sp.), liverworts, Marchantia,Conocephalum, Porella
Liverworts have actually the simplest bodies of all the eco-friendly plants. Thegametophyte,the dominant stage, looks favor a flat scaly leaf, with influential lobes.It watch for every the civilization like a small flattened liver, therefore thescientificname hepatico-phyta = liver plant. Throughout the center Ages, thissimilaritycaused medical professionals to prescribe liverwort for conditions of the liver.Accordingto the theory of Signatures the Creator had designed all of nature,includingplants, through our welfare in mind. People thought that plants had beenintentionally designed come resemble the organs of the body they weresupposedto heal! therefore liver-wort, wyrt being the Anglo-Saxon word because that herb.Theshape the the liverwort to be the signature of the Creator in nature. Canyou assumption: v what walnuts were supposed to healing ? (diseases the thebrain)
Liverworts re-superstructure the general properties of bryophytes, yet are notveryclosely concerned mosses or hornworts. Numerous botanists think they mayhaveevolved independently, native a different group of environment-friendly algae. Because that onething,liverworts don’t store food together starch but as oils. If you get theaquaticliverwort Porella in lab, take a sniff that the jar, but not toodeep!It smells that rancid oils, oils that went a tiny funky while the plantwas being shipped. An additional characteristic distinct to liverworts is theirlack of stomata, which are uncovered in all various other plants, consisting of mossesand hornworts.
In many varieties of liverworts, such together Marchantia, the oneyouwill most most likely see in lab, the antheridia and also archegonia space not ontopof the plant, however hanging under from the underside of weird littlestructuresthat look favor tiny umbrellas. (These umbrella-shaped frameworks arecalledthe antheridiophore and also archegoniophore). The bi-flagellated spermswimsto the egg, and also fertilization takes ar to form a diploid (2N)zygote.The small diploid sporophytes, which stay attrached to the parentplant,have a very an easy structure. Meiosis in ~ the sporophyte produces anumber of haploid spores. These spores room surrounded by curious longandtwisted moist cells called elaters. Once the capsule dries and bursts,the elaters twist and jerk around in a method that scatters the spores inall directions. Liverworts can also reproduce asexually by method ofspecialstructures dubbed gemmae cups. These small cups can be easilyseenon the surface of the plant. Every gemma cup contains a variety of tinyplantletscalled gemmae, and also a solitary drop the water will certainly disperse them. Theselittlevegetative “clones” will then flourish into a brand-new gametophyte.
Division Anthocerophyta - (100 sp.), hornworts, Anthoceros
The environment-friendly gametophytes that the hornwort look an extremely much choose aliverwort.But their tiny sporophytes much more closely resemble those the mosses. Thesporophytes flourish out the the gametophyte, and look like a tiny uprighthorn. Choose mosses, hornworts have actually stomata, and also so are more than likely morecloselyrelated to mosses and other plants 보다 to the liverworts lock matresemble.These plants are symbiotic with the cyanobacteria Nostoc. Thecyanobacteriafixes nitrogen for the hornwort.Taxonomy
Division Bryophyta - mosses (Mnium, Sphagnum; fr.Gr.bryon= moss)
Division Hepaticophyta - liverworts (Marchantia,Conocephalum,Porella; fr.Gr. Hepato = liver)
Division Anthocerophyta - hornworts (= Anthocerotophyta; Anthoceros;fr.Granthos = flower, keras = horn)Terms alternation the generations gametophyte gametangium (-ia) archegonium (-ia) antheridium (-ia) sporophyte sporangium (-ia) spore capsule protonema vascular mechanism gemmae gemmae cupTo Do and also View
Examine the living mosses on display. Notice the tiny capsuleson peak of the tiny sporophytes. Mosses generally prosper in one of twogrowthtypes: cushiony moss and feathery moss.
Examine slides the the antheridia and archegonia. The sausageshaped antheridia create sperm, and the flask shame archegoniaproduces eggs.
Examine slides that the moss capsule, and identify the spores.
Examine slides the the protonema. What form of algaedoesit remind you of? This same is extr evidence the greenalgaegave rise to all higher plants.
Examine the terrestrial liverworts Marchantia and Conencephalum(oneor both should be on display). How does their growth habit different fromthat the the mosses? have the right to you see any gemmae cups top top the uppersurfaceof this plants?
Examine slides the the liverwort Marchantia.
Examine the aquatic liverworts prefer PorellaandRiccia(one or both must be ~ above display). An alert how they different from themoreterrestrial develops of liverwort.
Look at the kept liverworts, and observe your distinctreproductive frameworks (they look like tiny green umbrellas). Howdoestheir life cycle different from mosses?
Examine slides that the hornwort Anthocerophyta.Things to Remember
Know the life cycle of the moss in detail, and also be maybe torecognizethe assorted stages.
Hint: Be certain you understand the basic life cycle ofplants,and can tell i m sorry stages space haploid gametophytes (1N) or diploidsporophytes(2N). We"ll discover several life cycles in lecture and in lab (moss,fern,pine, flowering plant), but all of them room variations on the samebasictheme.Ecological, Evolutionary, and also Economic Importance
Mosses are crucial in landscaping and also gardening, particularly peatmoss(Sphagnum).
Peat moss (Sphagnum) has been used historically together dressingsfor wounds.
Peat moss have the right to be supplied as fuel.
Mosses are the many primitive life land plants.
Hornworts save symbiotic swarms of the cyanobacteria Nostoc.
shining club moss
Introduction come Tracheophytes - Ferns and also Fern Allies
Tracheophytes (vascular plants) completed the conquest of theearth’s surface started by the an ext primitive bryophytes. Simply as theevolutionof spores to be the an essential to the intrusion of the land surface ar bybryophytes,the innovation of facility vascular tissues let tracheophytes completetheconquest of dry land. There are around 250,000 varieties of vascularplants,grouped in ripe divisions. Tracheophytes all have actually a fine developedroot-shootsystem, with highly devoted roots, stems, and also leaves, andspecializedvasculartissue (xylem and phloem) that duty like miniature tubes toconductfood, water, and also nutrients transparent the plant. Due to the fact that ferns and fernallies posses true vascular tissues, they can thrive to be much largerandthicker than the bryophytes.
The ferns and also fern allies (non-seed tracheophytes) mark two majorevolutionarystrides. In these and also in all an ext advanced plants, the leafy green diploidsporophyte now becomes the leading stage. The small gametophytemay be either autotropophic (like the fern prothallus) orheterotrophic(like the gametophytes of part lycopsids), and also is generally free livingand live independence of the parental sporophyte. Unlike the vascularsporophytes,the gametophytes have actually no vascular organization at all. This gametophytes aretherefore really small, and develop finest in moist areas, wherein they canabsorbwater straight from their surroundings.
Like the bryophytes, ferns and also fern allies room still restricted tomoisthabitats. Their flagellated sperm require a thin film of water come swimbetweenthe antheridium and also the archegonium. And also when the infant sporophyte growsup native the gametophyte, that is exposed to desiccation (drying up). Thisbasic strategy the a free-swimming sperm and also a non-motile egg is sharedby plants, animals, and also algae. It makes sense, because it means onlyoneset that gametes needs to make the perilous journey external of theorganism.
ground pine tree (Lycopodium) reflecting strobili
The ferns and fern allies germinate indigenous spores. These plants aremostlyhomosporous- your spores are identical and also you can"t distinguish which willgrow into male or female plants. Lock are also monoecious -boththe archegonia and antheridia (male and also female reproductive structures)are borne ~ above the exact same plant. Contrast these primitive vascular plantswiththe more advanced seed plants, the gymnosperms and also angiosperms, whichgerminatefrom seeds rather than native spores. Seed plants room all heterosporous.It is straightforward to distinguish the bigger female megaspore fromthesmaller masculine microspore. The sperm of particle plants have actually noflagella.They lack antheridia, and also only a few still have an archegonia. Unlikethemore primitive ferns and fern allies, seed plants are mostly dioecious,having separate male and female plants.
In many of these primitive plants, details leaves space specializedforreproduction. These modified leaves, or sporophylls, be afflicted with thesporangiaat their bases. These sporophylls normally branch out from a shortenedstem,forming a club shaped structure called a strobilus. The pineconeand the flower are fancy variations on this primitive strobili.
There are four divisions of non-seed tracheophytes, vascular plantsthat give birth by way of spores, the Psilophyta, Lycophyta,Sphenophyta,and Pterophyta. Before these non-seed tracheophytes evolved, thebryophyteswere the dominant form of tree life. The evolutionary edge of having actually amore effective conducting system, and also a well-developed root-shootsystemenabled them to outcompete bryophytes. If you’re lucky enough to seegroundpine or various other club mosses cultivation in the shade of a large pine tree,thinkfor a moment about how these tiny plants were once the master of theplanet,forming substantial forests through trunks from 20 to 100 feet tall!Taxonomy
Tracheophytes (vascular tissue, no seeds)
Division Lycophyta - society moss, quillworts (Lycopodium,Selaginella)
Division Sphenophyta - horsetails (Equisetum; fr.L.equus= horse)
Division Psilophyta - whisk fern (Psilotum)
Division Pterophyta - true ferns (Pteris; fr.Gr.pteridion= tiny wing)Terms homosporous heterosporous megaspores microspores rhizomes sporophylls strobilus (-i) sori indusium (-ia) prothallus fiddleheadsCharacteristics the Divisions
Division Psilophyta - (fr Gr. Psilo = smooth), whiskferns,Psilotum
There are just two living genera the whisk ferns, single survivors that alarge and widespread group of early land plants. In addition to thelivingDivision Psilophyta, the psilopsids, there room two extinct divisions ofprimeval vascular plants. The primitive whisk ferns resemble theseextinctpioneers in many ways. They room the only living vascular tree thatlacka root-shoot system, a characteristic lock share with both extinctDivisionsof ancestral vascular plants. Some current molecular evidence suggeststhatone, or even both, the the life genera that psilopsids might actually bemoreclosely pertained to ferns, favor a fern that has reverted to moreprimitivetraits. If this is true, then Psilophyta will join the ranking of thenumerousextinct divisions of plants.
Psilopsids are discovered in tropical and subtropical areas, and occursthroughoutthe southern US. Ns once uncovered one growing on my ago porch under theleavesof a spider plant. Whisk ferns space a usual weed in greenhouses alloverthe world. Castle are simple green upright stems, v dichotomousbranching.They have no leaves, and no true roots. The external tissues that the stemdoall the photosynthesizing. A part of the stem referred to as a rhizome runsalong the ground, or just listed below it. A rhizome is a horizontalstemthat spreads the tree around. Roots flourish out the bottom of therhizome,and a brand-new plant deserve to arise in ~ the same allude from the top.
The environment-friendly stem-like plant is the diploid sporophyte, the dominantstagein the life cycle. In the small sporangia (bright yellow) the formalongthe upper stems, the spore mom cell forms haploid spores through meiosis.Their gametophytes room tiny little thread-like underground plants thatlack chlorophyll, and also live together heterotrophs in the soil, looking andactingmuch prefer a small fungi. That actually consists of a symbiotic fungi, thesamemycorrhizae the live in the rhizomes that the adult sporophyte.
Division Lycophyta - (1,000 sp., fr. Gr. Lycos=wolf), clubmosses,quillworts, Lycopodium (podus=foot)
Their space only five living genera of lycopsids, but at one time fromthe far-off Devonian, about 400 mya, well right into the Carboniferous, theywere the dominant type of vegetation ~ above the confront of the Earth. Currently theyare diminished to a zero of your glorious past, inconspicuous littleplantsin the woodland understory. The tropical types are little epiphytes(plantsthat grow on other plants).
Their roots grow from special underground stems referred to as rhizomes, asdo most of this primitive tracheophytes. In some types thesporophyllsare combined in with the scale-like leaves. In countless species, thesporophyllsare organized into strobili, therefore the common name of “club moss”. Thesperm swim down the strobilus to the archegonia, and the zygote thatformsis kept in the cone, i beg your pardon ripens and also falls come the ground. Thegametophytesare independent and free-living, They are curious creatures that lookandact nothing favor their sporophyte parents. They can be eitherheterotrophicor autotrophic, and also usually have actually a symbiotic fungi associated withthem.Many of the lycopsids are heterosporous. Selaginella is a goodexampleof a heterosporous plant.
Division Sphenophyta - (15 sp., one genus, fr. Gr.sphen=wedge),horsetails, Equisitum
In rubbish places, disturbed locations like trails and also railroad beds, andin weird corners that fields and forests you could find another tiny plantquietly dreaming of its former splendor, the horsetail. Horsetailsappearedin the late Devonian, and also were amongst the dominant forest tree forhundredsof millions of years. Just one genus the Sphenophyta tho exists, thegenusEquisetum,and it may be the oldest living genus of plants on earth. Horsetailstoweredamong the Carboniferous forests, getting to heights that 30-60 feet. Muchofthe coal deposits we exploit for fuel this day were developed from horsetailsand various other trees during the Carboniferous, toward the end of thePaleozoic.
Horsetails have actually true roots, stems, and also leaves, despite the leaves arelittle much more than flattened stems. Your hollow, ribbed stems arejointed,kind of choose a stalk of bamboo, and also a whorl of leaves arises at eachjoint.The plants room spread vegetatively by rhizomes. The stems feel veryrough,because the epidermal tissues room impregnated with tiny grains ofsilica(sand). This probably helps safeguard the plant versus herbivores. Theserough stems made this plant appropriate for pioneer ladies to use forscrubbingpots and pans, therefore its other common name, “scouring rush”.
The green plant we watch is the diploid sporophyte generation. Thestalkscan be very branched vegetative stalks, which in reality look likehorsetails, or right unbranched reproductive stalks, which space tippedwitha huge strobilus containing the sporangia. The homosporous sporesdevelopinto a teeny-tiny eco-friendly gametophyte, just a few mm long, the lookslikethe gametophyte the a fern. The gametophyte is haploid, free-living, andautotrophic.
Division Pterophyta - (12,000 sp., fr. Gr. Pteridion=littlewing),ferns
Ferns probably developed from the psilopsids, sometime in theDevonian,relatively early in land tree evolution. Castle are very abundant anddiverse, varying in dimension from a single centimeter to trees 24 meterstallwith 5 meter fronds. Ferns have actually been better competitors v seedplantsthan various other seedless vascular plants, and also are a conspicuous component of thelandscape transparent the world, but especially in the tropics, where75%of their 12,000 species occur.
Ferns are fairly advanced plants, v true roots, tribe andleaves.The blade of the fern is dubbed a frond, and also the little individualleafletsare called pinnae. Ferns have true leaves, what botanists callmacrophylls.While the leaves of an ext primitive plants, which space calledmicrophylls,are simply expansions of the epidermis of the stem, the leaves of fernsand higher plants were created as a web of tissue stretched betweensmallterminal branches. The leaves of greater plants, and also the modifiedleaves that comprise the jaw cone and also the flower.
The life bike of the fern is usual of various other non-seed vascularplants.The leafy environment-friendly plant is the sporophyte. Productive fronds developsclustersof tiny sporangia ~ above the underside the the frond. This clusters ofsporangiaare dubbed sori (sing. Sorus). Sori space often protected by atinyumbrella-like cap referred to as an indusium (-ia). Ferns are mostlyhomosporous,though some room heterosporous. The heterosporous state is a moreadvancedcondition, that seems to have evolved independently in several groupsofplants.
The haploid spores are formed by meiosis inside the sporangium. They ejected in a miniature explosion resulted in by the unequal dry ofthealternate thick and thin-walled cells that line the external surface. Thetop traction slowly earlier until the reaches a vital point and then snapsforward at an incredible speed. At that dimension scale, the expulsion offernspores is one of the most explosive occasions in nature. The sporesgerminateinto small gametophytes. The tiny heart shaped gametophyte is called aprothallus,literally “first-body” (pl prothalli). The prothallus has no vasculartissue.Its tiny size lets it rely totally on diffusion. Its tiny rhizoidsareassociated v mycorrhizal fungi. The tiny prothallus is green, andphotosynthetic, and also bears either antheridia and archegonia, orsometimesboth together, on its upper surface ar (lab slides have actually both top top sameprothallus).The archegonia are always found at the arch the the heart, and theantheridiaare tucked away among the small rhizoids at the various other end. The spermswimsto the egg to fuse right into a diploid zygote. The new sporophyte growsdirectlyout that the top of the gametophyte. As soon as it an initial begins to uncurl, thefrond looks like the scrolled neck the a violin or fiddle, and thisstageof breakthrough is called a fiddlehead.
To Do and View
Examine the life lycopsids top top display. Why space they calledclub mosses? notice that quillworts and also Selaginella space verydifferentin appearance from the club mosses.
Examine slides that Selaginella"s strobilus. Recognize megasporesand microspores.
Examine the life horsetails top top display. An alert theprominentstrobiliofthe reproductive stalks, and also the bushy growth kind of the vegetativestalks(if available).
Examine the living whisk ferns ~ above display. Psilopsidshave a straightforward dichotomous branching pattern. You might see small yellowsporangiaon the branches. Whisk ferns absence strobili. This primitive tree areclosely concerned ferns.
Examine the living ferns top top display. Deserve to you see any type of fiddleheads?Look for the rhizomes. Rhizomes space modified horizontal stemsbearingroots, that operation along or simply underneath the ground, and spread fernsandfern allies around.
Examine the life fern prothallus on display screen under adissectingmicroscope. Keep in mind its characteristic love shape. Some prothalli mayhavea tiny brand-new fern arising from the notch of the "arch" heart, where thearchegoniaarelocated.
Examine slides the the prothallus: find the archegonia(can you view an egg?).
Examine the fern leaflet on screen under the dissectingmicroscope.Notice the prominent indusia, and the small sporangiapeekingout native beneath. You"ll see a few groups the sporangia that have actually losttheirindusium. If you"re lucky, together the warmth of the microscopic lense dries out theleaflet, you could see the sporangia eject that is spores. Yet don"tblink- it"s one of the fastest and also most explosive acts in nature. Use highpowerto observe the spores.
Examine slides of the sori and also indusia; usage high powerto watch the spores.Things to Remember
Know the life bicycle of the fern. Recognize specimens andslidesof the miscellaneous stages.Economic, Ecological, and also Evolutionary Importance
Ferns and also fern allies are mainly responsible for our moderndepositsof coal.
The fiddleheads the some varieties of ferns room edible.
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Ferns are vital for the florist, gardening and also landscapeindustries.Consider This
Why are all this plants minimal to wet habitats?
Which group of protists offered rise to this plants? (How carry out we know?)
Why is the epidermis the the horsetail therefore rough? What does it needprotectionfrom?
All the the fern allies in this lab once towered 50-100 feet or more.What happened?
Links to Explore
Bryophyte taxonomy, images, and more at:
Get info around bryophytes native the Missouri factory Garden at:
Lie down among the ferns in ~ the American Fern Society, shot theirlengthylist that links:
Basic details on ferns and fern allies, finish with images, courtesyof Texas A&M:
Look for ferns ~ above the "tree the life" at