Posts

Showing posts with the label Pteridology

Bacterial Transformation

-
  Bacterial Transformation Bacterial transformation is a process in which a bacterial cell takes up foreign or naked DNA from its surrounding environment and incorporates it into its own genetic material. This results in the acquisition of new genetic characteristics by the bacterial cell. Transformation is one of the major mechanisms of horizontal gene transfer in bacteria, along with conjugation and transduction. It plays an important role in bacterial evolution, adaptation, and genetic diversity. It is also widely used as an important technique in molecular biology and biotechnology. Discovery of Bacterial Transformation The phenomenon of bacterial transformation was first discovered by Frederick Griffith in 1928 while studying Streptococcus pneumoniae. He worked with two types of bacterial strains: the Smooth (S) strain and the Rough (R) strain. The S strain possessed a polysaccharide capsule and was pathogenic, whereas the R strain lacked a capsule and was non-pathogen...
Post a Comment
Read more

Comparison of Internal Structure of Leaf of Selaginella and Lycopodium

-
  Comparison of Internal Structure of Leaf of Selaginella and Lycopodium Feature Selaginell a Leaf Lycopodium Leaf Leaf type Microphyllous leaf; generally small, simple, and ligulate. Microphyllous leaf; simple and usually eligulate. General arrangement Leaves are commonly arranged in four rows and may be unequal in size, especially in dorsiventral species. Leaves are usually small, simple, equal in size, and commonly arranged spirally around the stem. Epidermis Single-layered epidermis is present on both surfaces and is covered by a thin cuticle. Single-layered epidermis is present on both surfaces and is covered by a cuticle. Cuticle Cuticle is generally thin, but it may vary according to habitat. Cuticle is usually well developed and may be thicker in xerophytic species. Stomata Stomata are present, usually more common on the lower/abaxial surface. Stomata are present, commonly on the lower surface or sometimes on both surfaces depending on specie...
Post a Comment
Read more

Comparison of Internal Structure of Root of Selaginella and Lycopodium

-
  Comparison of Internal Structure of Root of Selaginella and Lycopodium   Feature Selaginella root Lycopodium root Root origin Roots commonly arise from rhizophores; they are adventitious in nature. Roots arise adventitiously from the stem or rhizome. Root system Usually delicate, dichotomously branched roots. Adventitious roots, often dichotomously branched and comparatively firm. Epidermis / piliferous layer Outermost single-layered piliferous layer; root hairs may be present in young roots. Single-layered epidermis or piliferous layer; root hairs may be present in young roots. Cuticle Cuticle is absent or very thin because it is a root. Cuticle is absent or very thin. Cortex Cortex is well developed and usually parenchymatous, though some cells may become thic...
Post a Comment
Read more

Comparison of Internal Structure of Stem of Selaginella and Lycopodium

-
  Comparison of Internal Structure of Stem of Selaginella and Lycopodium Characteristics Selaginella Stem Lycopodium Stem Plant group Heterosporous lycophyte Homosporous lycophyte Stem nature Usually delicate and branched Usually firm and dichotomously branched Epidermis Single-layered epidermis with cuticle Single-layered epidermis with cuticle Stomata on stem May be present in young stem Usually few or absent on stem Cortex Well-developed cortex; often differentiated into outer sclerenchymatous and inner parenchymatous regions Broad cortex; commonly differentiated into outer, middle, and inner regions Outer cortex Generally sclerenchymatous and provides mechanical support Often sclerenchymatous or compact parenchymatous Inner cortex Usu...
Post a Comment
Read more