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Showing posts with the label Pteridology

Pleomorphism of Lysosomes

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  Pleomorphism of Lysosomes Lysosomes show pleomorphism, which means they occur in many different forms according to their functional state. They are not always identical in shape, size, or contents. Their appearance changes depending on whether they are newly formed, involved in digestion, or storing undigested waste materials.  Lysosomes are membrane-bound organelles containing hydrolytic enzymes. These enzymes digest proteins, lipids, carbohydrates, nucleic acids, and other cellular materials. Since lysosomes perform different digestive functions inside the cell, they appear in different structural forms. This property is called pleomorphism.  The main pleomorphic forms of lysosomes are primary lysosomes, secondary lysosomes, autophagic vacuoles, and residual bodies. Primary lysosomes are newly formed lysosomes produced by the Golgi apparatus. They contain inactive hydrolytic enzymes and have not yet taken part in digestion. They are small, spherical vesicles surround...
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Comparison of Internal Structure of Leaf of Selaginella and Lycopodium

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  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...
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Comparison of Internal Structure of Root of Selaginella and Lycopodium

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  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...
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Comparison of Internal Structure of Stem of Selaginella and Lycopodium

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  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...
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