Hepatophyta and Anthocerophyta Flashcards
Bryophytes include what
Liverworts
Hornworts
Mosses
Living, non-vascular plants
Hepatophyta
Anthocerophyta
Common names
Liverworts
Hornworts
Why does thallose mean?
What groups of hepatophyta are thallose?
Gametophytes that are flattened dorsal-ventrally
Metzgeriales
Marchantiales
What generation is dominant in bryophytes
Gametophyte!!
Sporophyte is small and short lived
Order Jungermanniales
-characteristic appearance
-habitat
-Leafy liverworts
-2 lateral rows of leaves and underleaf reduced row (amphigastria) on gametophyte stem. Leaves and stems lack cuticles
-sub-tropical
The leaves of Order Jungermanniales resemble those of mosses in that they consists of a single layer of _______. But differ because they lack a _______
Undifferentiated cells (unistratose)
Costa (midrib)
Water absorption in Jungermanniales
Occurs directly through the cells of leaf surfaces, as both the stems and leaves lack cuticles.
The dense mat habit of leafy liverworts, couples with the overlapping of leaves and leaf lobes, provides an extensive surface over which water my pads by capillary action
Plants of many taxa in the Jungermanniales are _______
Dioecious- male and female plants
Antheridia and archegonia of Jungermanniales
Antheridia are borne singly in the axils of densely overlapping bract-like leaves on a specialized branch called the antheridial branch. Each antheridium is composed of a short stalk, an antheridial jacket of sterile, protective cells that surround the spermatocyte, also known as sperm mother cells, mitosis occurs within the Sperm mother cells and thus they produce biflagellate sperm.
Archegonia are produced on short, lateral branches of the female plants. The archegonial branches are scarecrow different from young vegetative branches until later in their development and are often difficult to recognize.
How do sperm reach archegonia in Jungermanniales
Little is known. However, the fact that male and female plants often grow intermingled in mats: the continuous capillary spaces exist between the plants and the substratum, and that leaf surfaces overlap, suggests that a convenient avenues exists for the dispersal of the motile sperm.
The leaves that surround each group of 8-10 archegonia develop into a ________ after fertilization has occurred
Order Jungermanniales
Perianth
Order Jungermanniales
____ zygote usually develops into a sporophyte on each gametophyte shoot, even through the eggs of several archegonia may be fertilized.
1
Order Jungermanniales
The sporophyte is differentiated into what sections
Capsule-where meiosis occurs to produce haploid spores
Seta - elongate to thrust capsule out of the Perianth
Foot-embedded in the enlarged tip of the gametophyte stem from which it derives nutrition
What is found amongst the spores in order Jungermanniales
Elaters - hygroscopic threads
Sporophytes develop from the embryo of a fertilized egg inside an ________
Archegonium
The capsule is surrounded by the _______
Calyptra - covering over the sporophyte capsule that is derived from the expanded archegonial wall
The capsule splits where in order Jungermanniales
Suture lines leading to spores being shed into the wind
How do spores germinate in order Jungermanniales
Spores germinate by producing a protonema that resembles a filamentous green alga; however this will give rise to buds that become the new leafy gametophyte generation
Thallose Liverworts
-habitat
-types
Non- leafy helatophyta
-moist, shaded stream banks
-Order Metzgeriales: simple thalli, Order Marchantiales: complex thallus
What makes Order Metzgeriales unique from Order Marchantiales
They have no ventral scales or air chambers
Order Metzgeriales
-branching
-appearance and reasoning
-dichotomous branching
-smaller, smoother and more translucent than Marchantiales
-smoother because of no air chambers and pores on the upper surface of the thalli.
-most cells contain chloroplast
Order Marchantiales
Gametophytes of this order of liverworts are internally ___ into ______ called ______
Stratified into several layers of tissues called multistratose
-upper most layer are photosynthetic and are contained within air chambers which are open to the outside through small pores in upper surface
-lower layers of cells in the thallus are used for storage and usually do not contain chloroplasts.
-there are rhizines and multicellular scales on the under surface of the thallus
Rhizoids and scales purpose
Anchor and store/ conduct water
Order Marchantiales have gametangia that are restricted to specialized structures called ________
Gametophores
The male and female gametophytes can be easily identified by their gametophores, which are structurally quite distinct from one another.
Differentiating male and female gametophores
Order Marchantiales
Antheridia are borne on disk-headed stalks called antheridiophores, whereas the archegonia are borne on umbrella-headed stalks called archegoniophores
Order Marchantiales
Each sporophyte consists of a ______, _____ and ______
Foot
Seta (short stalk)
Capsule (sporangium)
Order Marchantiales
Mature sporangia also contain ______
Elaters: elongate cells which have spirally arranged hygroscopic (moisture absorbing) wall thickenings that aid in spore dispersal after the capsule has dehisced.
Asexual reproduction in liverworts
Fragmentation; however Gemmae are also common. Gemmae are small, multicellular, undifferentiated organs that give rise to new gametophyte plants.
In Order Marchantiales, Gemmae are produced in special _______ structures called _______
Cup-like structures
Gemmae cups located on the dorsal surfaces of gametophytes
Class Anthocerotopsida
Habitat
Shaded, habitats in sub-tropical and warm temperate regions
Class Anthocerotopsida
Gametophytes superficially resemble those the the ______ liverworts
Thallos
Class Anthocerotopsida
-Characteristics
-dorso-ventral orientation; are often rosette-like and are usually less than 2 cm.
-gametophytes have extensive internal cavities filled with mucilage, not with air. These cavities are often Inhabited by Cyanobacteria.
-antheridia and arching is are sunken into the dorsal surface of the gametophyte.
What do Cyanobacteria do for Class Anthocerotopsida
Supply nitrogen to their host plants by the process of nitrogen fixation
Are species in Class Anthocerotopsida unisexual or bisexual
Can be either
Sporophytes of Class Anthocerotopsida
Numerous sporophytes may develop on the same gametophyte. Each sporophyte consists of a foot, a long sporangium. A meristem develops between the foot and the sporangium very early in development. The meristem is active as long as conditions are favourable for growth, as a result the sporophyte has several layer of photosynthetic cells and it’s surface is covered with an epidermis with stomata and a cuticle.
-Small tubular growth of the gametophyte called an involucre grows upwards around the base of the sporophyte
How are spires released in Class Anthocerotopsida
Dehiscence of the sporangium begins at its tips and spreads toward its base as the spores mature. The dehiscence sporangium splits longitudinally into ribbon-like valves to release the spores
