Nature of the Endosperm in Angiosperms

Nature of the Endosperm in Angiosperms   Nature of the Endosperm in Angiosperms Nemec (1910), brink and Copper (1947), suggested that fusion of second male gamete with the polar nuclei serve two functions: It stimulates the development of endosperm. It helps in the formation of the tissue which is physiologically more suitable for the nourishment of the embryo. Thus, it ...

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Development of Monocot Embryo of Angiosperms

Development of Monocot Embryo of Angiosperms (Sagittaris sagittifolis) Development of Monocot Embryo The oospore divides to form a Proembryo which is a filament consisting of three cells, a large Basal Cell, a Middle Cell and a Terminal Cell. The basal cell is present towards micropylar end. It enlarges in size forming most of the suspensor. The middle cell divides repeatedly ...

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Fertilization In Angiosperms

Fertilization In Angiosperms Fertilization The pollen tube after entering the embryo sac bursts and during this process one of the synergids is also destroyed. The tube nucleus disintegrates. One of the male gametes move towards the egg and fuses with it (syngamy) and the other male gamete fuses with the secondary nucleus (triple fusion). This process is known as Double ...

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Types Of Embryo Sacs Of Angiosperms

Types Of Embryo Sacs Angiosperms Types of Embryo Sacs The previously mentioned development of female gametophyte is that of a Normal Type 8 -nucleate monosporic embryo sac. However, there are several variations from this normal type and the embryo sacs are divided into categories on the basis of these variations. Monosporic Type The embryo sac of this type may be ...

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Development Of Ovule Of Angiosperms

Development Of Ovule Of Angiosperms           The ovule primordium appears as a protuberance on the surface of the placenta. It grows into a conical structure with rounded tip. This is the Nucellus or Megasporangium Proper. From the base of the nucellus, one or two layers of tissue develop, which grow upward and form the integuments. The inner integument develops first ...

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Megasporophyll Or Carpel Of Angiosperms

Megasporophyll Or Carpel Of Angiosperms Gynoecium or pistil is the female reproductive whorl of flower consisting of one or more carpels or Megasporophll. The carpel is an elongated appendage and is a modified folded leaf. The folding encloses Megasporangia (ovules) in a chamber, the locule. Each carpel consists of three parts Stigma, which receives pollen grains. Style slender projection of ...

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Microspores Of Angiosperms

Microspores Of Angiosperms Microspores  Each Microspore is a unicellular, uninucleate structure, possessing two coats, the outer Exine and the inner Intine and contains a large central nucleus and dense cytoplasm. The exine is thick, cuticularized and tough layer and it is often provided with spinous outgrowths, warts or reticulations and sometimes smooth. The intine is thin, delicate, cellulosic layer lying ...

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Development of Microsporophyll of Angiosperms

Development of Microsporophyll of Angiosperms           Each microsporophyll (stamen) arises as a small papillate outgrowth of meristematic tissue from the growing tip of the floral primordium. It grows actively and is differentiated into an apical border portion, the anther and a lower slender part, the Filament. The transverse section of a very young anther shows that it consists of a mass ...

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Embryology And Development Of Angiosperms

Embryology And Development Of Angiosperms Life cycle of an angiosperm comprises of two generations, the Sporophytic and the Gametophytic. These two generations alternate with each other in regular sequence. This phenomenon is known as Alternation of Generation. The angiospermic plant, that is usually differentiated into roots, stems, leaves and flowers, is the Sporophyte as it consists of diploid cells (2n). ...

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Super Kingdom prokaryota and Eukaryota

Super Kingdom prokaryota and Eukaryota All cellular organisms so far studied fall naturally into one of two major groups, the prokaryota and eukaryota The prokaryotes appeared about 3500 million years ago and comprise a variety of organisms collectively known as bacteria. All the cells of prokaryotes (pro=before+karyon=nucleus)lake true nuclie. In other words their genetic material (DNA) is not enclosed by ...

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