LIFE CYCLE OF MARSILEA PDF
Here are your notes on the life history of Marsilea! Characteristic features: This order includes a single family, Marsileaceae. The family includes the living. Etiology Thiaminases occur naturally in Marsilea spp., Cheilanthes spp., Figure A. Growth habit and reproductive structures of the sporophyte polypody fern. .. that centriolar duplication connected to the cell cycle is a secondary event. Download/Embed scientific diagram | – Life cycle of a Heterosporous Pteridophyte (eg: Marsilea) from publication: Diversity of Pteridophytes in Western Ghats.
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Some antherozoids enter the gelatinous envelope, some reach the neck of the archegonium and others fail to do so. Then there is other cortex constituting of large air spaces or lacunae aerenchyma separated from each other by septa. The tissues slowly swell up by absorbing water in natural conditions. In this way the continuation of different tissues in the form of complete ring in stele is as follows—outer endodermis, outer pericycle, outer phloem, xylem, inner phloem, inner pericycle and inner endodermis.
A receptacle develops at the region where each lateral vein forks dichotomously. After the microspores and megaspores are shed from the sporangia, separate male and female gametophytes develop. Here’s how it works: The jacket cell in each antheridium does not divide again. The megaspore is liberated by the disintegration of the megasporangial wall.
At night the pinna are folded upwardly. The coiling looses at the time of fertilization. The apical cell divides transversely to form 2 equal antheridial initials Fig. In submerged species, the rhizomes possess usually a parenchymatous pith, whereas the plants growing on mud have a more or less sclerenchymatous pith.
At night the pinnae of aerial leaves become folded upwards and exhibit the sleeping movement. The lower tooth is stouter than the upper one.
There may be one or two nucleoli in the big nucleus. Leave a Reply Click here to cancel reply. Habit of Marsilea 2.
The V-shaped mass of xylem is surrounded by phloem and single-layered pericycle successively. The roots are adventitious, arising from the underside of the node of rhizome, either singly or in groups. In this article we will discuss about: Both the sori contain megasporangia if the section is taken through the megasporangia or the sori contain only microsporangia if it is taken through the microsporangia.
As the sorophore expands and pushes out, it pulls out the sori, which are attached to it by their ends. Epidermis is single layered made up of broad and columnar cells. Hypodermis consists of two layers of radially elongated palisade like cells.
Similarly, the third sporocarp initial arises. The spongy tissue is made up of loosely arranged parenchymatous cells with large air spaces separated by single layered septa.
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The mature sporophyte is an herbaceous plant. The small cell lies within apical protuberance. Thus, in both types of sporangia, i.
Just beneath the outer endodermis there is a single layered pericycle. These spores are produced in microsporangia and megasporangia, respectively.
They are the rudimentary sori which could not develop. The male and female nuclei fuse to form a diploid structure called oospore or zygote.
The leaves are borne alternately along the upper side of the rhizome at the nodes.
The morphological nature of the sporocarp of Marsilea has been controversial. The jacket initials divide anticlinally and give rise to the jacket layer of the sporangium.
The species of Marsilea possess a rhizome which creeps on or just beneath the surface of the soil. Microspore gives rise to make gametophyte which, in turn, produces archegonium and egg.
Marsilea: Habit, Structure and Reproduction
In the centre of the stele there is typical diarch and exarch structure with a diametric plate like strand of xylem. It consists a ring of air chambers. Simultaneously, the central cell divides into two cells, a small primary canal cell and a large primary venter cell.