Bryophytes: Liverworts, Hornworts and Mosses.

Transcription

1 Bryophytes: Liverworts, Hornworts and Mosses.

2 Bryophytes Plant scien+sts recognize two kinds of land plants Bryophytes, or nonvascular plants Tracheophytes, or vascular plants. Distribu+on tropical rainforests, arc+c tundra, and desert boulders

3 Chlorophyta and Bryophyta Charophyta Chloroplasts with grana Disintegra+on of nuclear membrane during mitosis Phragmoplast during cytokinesis Oogamus sexual reproduc+on Zygotes remain adached to the parental thalli The parental cells develop transfer cells involved in bringing sugars to the zygote Plasmodesmata

4 Bryophytes and other land plants. Kingdom Plantae Mul+cellular diploid sporophyte Produc+on of sporogeneous +ssue Tissues produced by an apical meristem.

5 Bryophytes. Non vascular plants Specialized cell for conduc+on Not lignified cells Large free living gametophyte Sporophyte Achlorophyllous Parasi+c on the gametophyte Unbranched One sporangium Plasmodemata

6 Bryophytes. Non vascular plants Cu+cle Pores Rhizoids Disk- shaped plas+ds in the thalli hexagonal leaf cells with central pore

7 Asexual: ReproducAon of Bryophytes archegoniophore (female sex organ) Sexual: Fragmenta+on Gemmae Antheridia Archegonia Gametpohytes are haploid Gametes produced by mitosis Bryophytes need water for fer+liza+on to occur.

8 Sporophyte of bryophytes. Sporophyte of mosses and hornworts contain stomata and two guard cells. brings up nutrients from the gametophyte through the placenta.

9 Spores covered with sporopollenin. Cellulose xylan lignin Lipids Extremely resistant to decay and chemicals

10 Bryophyta:Phylums/Divisions HEPATOPHYTA - the Liverworts ANTHOCEROPHYTA - the Hornworts BRYOPHYTA - the Mosses The Liverworts (wyrt= herb) 6,000 Gametophytes develop directly from spores but some produce protonemata Gametophyte leafy thalloid HEPATOPHYTA (hepaacs) - the Liverworts

11 Thalloid liverworts Differen+a+on of the thallus into 1. an upper photosynthe+c region with air chambers 2. a ventrally storage zone with abundant lipid reserve and rhizoids.

12 Thalloid liverworts Marchan'a produces the sex organs in Antheridiophores è antheridia. Archegoniophores è archegonia. Elaters to help in scadering the spores. Fragmenta+on Gemma cups Sporophyte

13 Leafy liverworts 4000 species Leaves generally are monostroma+c Antheridia produced on the androecial branches. The archegonium is surrounded by the perianth.

14 ANTHOCEROPHYTA - the Hornworts 100 species Gametophy+c thallus lobed or dichotomous The thallus has internal chambers with Nostoc Rhizoids are unicellular Stomata Most species are bisexual..

15 Gametangia develop from superficial cells but never project above the surface Sporophyte: Foot embedded in the gametophyte Long capsule or sporangium. intercalary meristem between the foot and the capsule meristem remains ac+ve indeterminate growth photosynthe+c

16 BRYOPHYTA - the Mosses 12,000 species Protonema Mul+cellular rhizoids Gametophyte Leafy with more than three ranks of blades Chlorophyllous May or may not branch.

17 Protosphagnales appear about 290 million years ago in the Permian. Sphagnum has apical gametangia Sporophyte capsules develop on the pseudopodia BRYOPHYTA - the Mosses

18 BRYOPHYTA - the Mosses explosive operculum closes the opening of the sporangial capsule Sphagnum can absorb water up to 20 +mes its dry weight Sphagnum releases large amount of H+

19 Class Andreaeidae 101 species granite or calcareous rocks in northern la+tudes Rhizoids consist of two rows of cells Sporophyte Foot Capsule ü four valves that open when is dry and close when is moist.

20 Class Bryidae Protonema uniseriate branched system that precedes the gametophores. major photosynthe+c role. Mul+cellular rhizoids present The sporangium opening with peristome.

21 What evidence is there in support of a charophyte ancestry for plants? APendance