FILICOPHYTA LECTURE HELPER Cmparative Bilgy f Plants 50-222 Blmsburg University f PA (= Pterphyta, Pteridphyta) ca. 10,000 spp. n strbili mst are hmsprus megaphylls stem steles: ectphlic siphnstele, amphiphlic siphnstele, r dictystele EUSPORANGIATE CLASSES Ophiglsspsida hmsprus gametphytes subterranean, fleshy, cylindrical, assciated with endphytic fungus Ophiglssum, Btrychium Marattipsida hmsprus gametphytes, epiterranean, phtsynthetic and assciated with endphytic fungus Angipteris, Marattia (trpical, subtrpical tree ferns) ancient tree ferns were prevalent in Late Carbniferus thrugh the Triassic LEPTOSPORANGIATE CLASS Filicpsida hmsprus and hetersprus rders gametphytes epiterranean, phtsynthetic, nt assciated with fungi three rders: Filicales hmsprus - many examples, Adiantum, Plypdium Marsiliales hetersprus Marsilea, Pilularia Salviniales hetersprus Azlla, Salvinia 1
Btrychium Ophiglssum Angipteris Marsilea Azlla Plystichum 2
BASIC SPOROPHYTE BODY PLAN Aerial Stem Marattipsida nly Rhizme with adventitius rts all taxa Leaves called frnds cnspicuus phtsynthetic, at least initially emerge with circinate vernatin (called a fiddlehead ) Sprangia brne n frnd (technically sprphylls) in clumps called sri (pl. srus) 3
FILICOPSIDA leptsprangiate (usually a definite number f spres/sprangium; 48 64 (-512)) ca. 300 genera and 9,000 species FOCUS ON FILICALES mst f ur familiar ferns hmsprus exspric gametphyte develpment spre germinatin influenced by light quality red/far-red - phytchrme influenced by chemicals e.g. thelypterin ALLELOPATHY gametphytes mnœcius ptentially bisexual gametangia n ventral surface, need liquid water fr antheridial dehiscence, releasing multiflagellate sperm all male r prtandrus (antheridia first, then archegnia) sexual develpment f gametphytes related t chemical messengers released int the envirnment called ANTHERIDIOGENS (related t gibberellic acids 4 and 7) crdate gametphytes prduce and release stimulate yunger (pre-crdate) gametphytes t prduce antheridia as gametphytes becme crdate, they becme insensitive t antheridigen, then they frm archegnia and secrete antheridigen themselves 4
SPOROPHYTE f Filicales Stem tissues are primary, even extinct and extant tree ferns; high develpment f sclerenchyma xylem develpment is exrach r mesarch a few have vessels stele types prtstele in a few primitive taxa siphnsteles ectphlic, e.g. Osmunda amphiphlic (slenstele), e.g. Dennstaedtia dictystele, e.g. Pteridium and Plypdium 5
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Frnd Dissectin 7
Leaf Venatin and Psitin f Sri Sri, Sprangia and Indusia 8
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APOGAMY and APOSPORY Apspry frmatin f a 2N gametphyte frm a vegetative cell r cells f a sprphyte (mstly an in vitr phenmenn) E.g. Adiantum pedatum Mrel shwed that juvenile leaves f yung sprphytes will prliferate int gametphytes in culture. Mrel, G. 1963. Leaf regeneratin in Adiantum pedatum. Jurnal f the Linnean Sciety f Lndn, Btany 58:381-383. Apgamy develpment f a sprphyte frm smatic tissue f a gametphyte (just behind the apical ntch). Antheridia and archegnia may be present, but nnfunctinal. Gametphyte and derived sprphyte have same chrmsme number. Sensitive t nutritient levels (sugars) in the envirnment, and t grwth regulatrs such as GA and ethylene. In bligate apgamy, sprangial develpment is altered need a cmpensating mechanism. 10
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Ferns have high chrmsme numbers. Are they plyplid? Sltis, D.E., and P.S. Sltis. 1987. Plyplidy and breeding systems in hmsprus Pteridphyta: a reevaluatin. American Naturalist 130:219-232. hmsprus ferns have th highest chrmsme numbers knwn fr any rganism typical, average fern - - 2N 100 highest fern - - 2N = 1260 typical, average flwering plant - - 2N 32 it was assumed fr a lng time that ferns were plypid, and that the large number f chrmsmes reflected chrmsmal dubling in the evlutinary histry f ferns Analyses f genes cding fr iszymes indicate that f the 652 lci surveyed fr ver 30 hmsprus ferns, nly 6 culd have arisen thrugh plyplidy. (Side nte, primitive magnliphytes with high chrmsme numbers are f ancient plyplid numbers). Explanatin? One explanatin is chrmsmal fissin. Are hmsprus ferns, with mnœcius and ptentially bisexual gametphytes intragametphytic selfers? Sltis, D.E., and P.S. Sltis. 1992. The distributin f selfing rates in hmsprus ferns. American Jurnal f Btany 79:97-100. 16 species had intragametphytic selfing rates 0 0.2 2 species had intragametphytic selfing rates 0.21 0.4 2 species had intragametphytic selfing rates 0.81 1.0 (Btrychium spp.) Inbreeders had much genetic structure (partitined ppulatin) Dry, patchy envirnments favr inbreeding. 12