Growing Root Classes

Introduction In this section we are going to discuss about the reproduction of Selaginella. Selaginella reproduce manily two ways Vegitative Reproduction and sexual reproduction Vegitative Reproduction In vegitative Reproduction mainly 4 processes are takes place * Fragmentation * Dormant buds * Bulbils * stem-tubers Fragmentation * During favorable conditions * Prostate branches produce roots * These branches brake * New sporophyte produced Dormant buds * Produced in areal branches * During favorable conditions * Develop in to new plant Stem-tubers * Produced at the apices of areal branches * During favorable conditions  * Develop in to new sporophytic plant body                                                                           Sexual Reproduction Sexual reproduction occurs by formation of s...

Introduction Internal morphology of plant shows the structure and arrangement of cells in the plant body. In this section we are going to have a look to internal morphology of selaginella stem,leaf,root & ligule                                                                                    Selaginella sporophytic plant body   STEM *  Cutinised *  Divided in to 3 regions. Epidermis, cortex, vascular cylinder or stele *   Epidermis - uniseriate - prosenchymatous (  plant tissue consisting of long narrow cells with pointed ends) *  Devoid of stomata  and hairs * Cortex  :- multiseriate - compactly arranged parenchyma cells *  In maturity cortex is differentiated into two *  Outer cortex - thick walled lignified pa...

Introduction Human genetics is simply the study of the inheritance of human traits. Congenital abnormalities, malformations, disorders and diseases. The milestone of the genetics is Mendelian law                     The branch of science which study this area is called human genetics From 1908 . from second half of 20 th century, human genetics become one of the most exciting branches of biological science, with extensive applications in the study and treatment of several human defects and diseases and also in the qualitative racial improvement of mankind. NORMAL HUMAN KARYOTYPE *  All the somatic cells of human being have same number and type of chromosom es  (23 pairs= 46 chromosomes) *  It signifies the number, size, kind, shape structure and other morphological features of chromosomes *  Graphical / diagrammatic representation of karyotype is called as karyogram or Idiogram *  chromosomes number - som...

Introduction External Morphology A pteridophyte is a vascular plant that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden.                                                                          One of the plant belongs to the group pteridophyte is Selaginella                        Habit of Selaginella *  Commonly called as spike moss or small clubmoss    *  Show Cosmopolitan distribution *  Almost 700 species Verity *  Shows wide range of habit. Shaded moisture tropical forests, extremely dry conditions, on tree trunk etc... * They act as free living, epiphyte, xerophytes etc.. ...

Introduction Gymnosperms are the plants that doesn't produce flowers. So their reproductive structures are cones. Cycas is one of a plant belongs to the group gymnosperms VEGITATIVE REPRODUCTION vegetative reproductive structures of cycas is called bulbils  or  adventitious buds                        bulbil of cycas *  Develop in the basal part of the stem, in the crevices between persistent leaf base  *  Decurrent base is covered with scale leaves and a few foliage leaves,develop from the centre. * After falling on soil, develop to a new one *  Male plant bearing bulbil develop as male cycas  *   Those from female plant develop as female cycas SEXUAL REPRODUCTION Cycas is a dioecious plant ( male and female on different plants ) MALE CONE *  Microsporangiate strobilus * Develop singly at the apex of stem *  Stem may get arrested for the crown *  Growth ...

Introduction The history of plants on Earth is many million years old. During this long period where's the varieties of plants emerged on earth. They disappeared due to climatic changes or due to catastrophic events such as earthquakes landslides volcanoes                    most plants of the geological past were decomposed by bacteria after their death a few plans for their parts got buried deep in the soil without decomposition. These planst and plant parts remained well preserved in the sedimentary rocks of the different ages they are called fosills .                   Paleobotany is the study of  fossil plants NOMENCLATURE OF FOSSILS rules governing the nomenclature of living plants are equally applicable to fossils also. fossilization mainly depends upon the hardness and softness of different tissues, so it is very difficult to find out whole fossil structure of a particular pl...

In this section we are going to discuss about the root and shoot systems of angiosperms Introduction Angiosperm plants are the plants which produce flowers. Like all other category of plants angiosperm plants have there on morphological and anatomical features . We can clearly distinguish whether the plant is gymnosperm or angiosperm. ROOT SYSTEM Root system is positively geotropic, Which gross towards the earth. Features of root system is broadly classified into two categories namely TAPROOT & ADVENTITIOUS ROOT TAPROOT Breathing roots This type of rules are the breathing roots. Help to gaseous exchange. Eg : pneumatophores  Storage roots  In tab root system there are mainly 4 types of food storage is occurs namely *Conical  *Fusiform *Napiform *Tuberous Conical : Conical food storage structures are like cons there for it is called conifers  Eg: carrot fusiform  : Fusiform food storage structures are example for radish Napiform : this type ...

Introduction   DNA are the storage site , that contains or codes our characters. And the DNA are the hereditary material that carries the informations Main features of DNA   * Deoxyribonucleic acid * Also known as 'B' DNA  * A type of nucleic acid  * polymer of nucleotides * Double helical structure ( Watson and Crick model ) * Double stranded structure * 2 strands are antiparallel to each other * Pentose sugar & phosphate are the back-bone * Consist of 4 nitrogen bases adenine (A), cytosine (C), guanine (G), or thymine (T).  * A form double bond with T * G form tripple bond with C * Adenine & guanine are purines * Cytosine & thymine are pyrimidines * One turn of DNA consists of 10 bonds of nitrogen bases ,360A°. So the distance between each bonds there were 3.6A°. Length of one turn is 34A°  * 20A° as width SHALLOW GROOVE & DEEP GROOVE Deep groove is also known as minor groove Shallow groove's another n...

  Author: Anjana Mambully There is a correction in the video which i posted in YouTube: Correction: (mature anther) that section is the c.s of anther .not c.s of pollen.