Biological World

  Reproductive Structures of Pteridophyte The Pteridophyte sporophyte, besides being a prominent component of soil and vegetation, is an important ornamental plant in gardens and lawns. Indoors, its gracefulness and shape fit it ideally as a plant for pot culture in hallways and living rooms, especially during the months of November to March. Transportation of whole plants from one place to another without damage is attempted by packing them in sand, decomposed silt, ashes, or sawdust. Despite their rich horticultural value, many Pteridophytes are vanishing from nature due to indiscriminate destruction of their natural habitats and capturing of species for ornamental purposes. The best means of conservation is an adequate botanical knowledge of these plants, together with their habitats. The approaches of the non-destructive collection of herbarium specimens are now being stressed. The collection is also supplemented with data regarding the locality and habitat, so as to make it de...

Leaves of pteridophytes Leaves of pteridophytes are variously called phyllidia, fronds, foliage, or simply leaves. When metamorphosed to a leaf-stalk, it refers to a petiole. They exhibit the greatest diversity in size, shape, texture, form, and position. Leaves are primarily for photosynthesis, and many pteridophytic plants produce leaves of more than one kind, commonly termed as dimorphic . The following forms are commonly found among pteridophytes. 1. Elongate. In this case, the leaf is elongated but uniform in width at least for the greater part, the width tapering only towards the apex. The common examples are: Macrothelypteris torresiana, Oleandra wallichii, Pteris longifolia, Polyurhythmopityrhis bifida, and Cephalomanes biswasii. 2. Filiform or capillary. The width of the leaf bears only a very small proportion to its length. The common examples are: Stenochlaena palustris, Thelypteris acuminata, Tectaria braunii, Pteris kinabaluensis, Elaphoglossum pumilum, and Linochelium...

  Structures of Root of Pteridophyte The earliest diverging branched axes of extant vascular plants, lycophytes, are characterized by the presence of purely structural roots whose only function is anchorage, and these plant groups include forms with very complex rooting systems. The rooting structures of the most basal branch is a single unbranched rooting axis strongly resembling a root-like organizational strategy of geotropically-growing axes found in the common ancestor of mosses and liverworts. Aquatic rooted forms of this grade of morphological diversity became established in early prediluvial times when no earth surface was free from water. Structures on axes that carried out rooting functions in plants appeared very early in the evolutionary history of land plants. The earliest land plants did not have true roots as they are defined today, that is, as organs carrying out anchorage and absorption functions that developed from a root meristem covered with a root cap. Instead,...

  Introduction to Pteridophytes Pteridophytes or ferns are a group of vascular plants with well-developed roots, stems, and leaves, or more usually, fronds, which reproduce via spores and have neither seeds nor flowers. True ferns are the largest group of pteridophytes, although the term is sometimes used to cover all the members of the clade . Accounting for around 10,600 species, they occur in a variety of habitats, particularly in warmer areas, and many have ornamental or agricultural uses such as the maile, a Hawaiian form used in decorations. The pteridophytes depend on a constant supply of water for the maturation of the spores. Most of them require shade for germination, initial development, and rooting. Though atmospheric humidity is advantageous, too much of it becomes detrimental for their growth. Their reproductive habits and the physiochemical nature of life, sap, or juices make them peculiarly vulnerable to drought or desiccation. They take years to produce young plant...

Mitochondria are organelles involved in respiration and energy production in eukaryotes. The shape, number, size and even ultra structure of mitochondria vary between cells, tissues and organisms. Progress in the field of 3D imaging of ultra structural refinement by cryo electron tomography, largely using cryo scanning electron microscopy and focused ion beam/SEM procedures, has greatly enhanced our understanding of cellular complexity. Mitochondria are large organelles (0.5-5.0 μm) in most mammalian cells and show a highly complex ultrastructural architecture. They are surrounded by two membranes, the outer mitochondrial membrane (OMM) and the inner mitochondrial membrane (IMM), which are separated by the intermembrane space (IMS) and the mitochondrial matrix, respectively. Mitochondria have morphological substructures adapted to the requirements of cellular metabolism that arise from invaginations of the IMM into the matrix space. The rigid and smooth part of the IMM is termed the in...