Farooq Lone

Plant Tissue Culture Techniques

Plant tissue culture is a technique where a very small piece of plant tissue, such as shot apex, leaf section, or even an individual cell is excised (cut-out) and placed in sterile or aseptic culture in a test tube, Petri dish or any culture vessel containing nutrient culture medium. The culture medium contains a gel (agar) with a proper mixture of nutrients, sugars, vitamins and hormones, which causes the plant part to grow at very rapid rates to produce new plantlets. Tissue culture is used for rapid multiplication of plants.

Taxonomy & Diversity of Euphorbiaceae

The Euphorbiaceae is commonly known as the spurge family. The term ‘spurge’ is derived from the Old French word ‘espurgier’, which means ‘to purge’. The family takes its name from its type genus Euphorbia; the latter has its origin from ‘Euphorbus’ who was Greek Physician to the King Juba II of Mauretania. The family was first established as a formal taxonomic category by A. L. De Jussieu in 1789 in the Genera Plantarum.

Leaf Arrangement: Morphology & Structure

Typically leaves are flat and thin organs of a plant and have one surface towards the axis (the adaxial, or upper surface) and another facing away from the stem axis (the abaxial or lower surface). Most of the leaves are bifacial, in having definite adaxial and abaxial faces, but some leaves are unifacial. Leaves are commonly arranged on the plant in such a way so as to expose their surfaces to light as efficiently as possible without shading each in order to promote the photosynthetic functions.

Aims & Objectives of Taxonomy

The term taxonomy has often been used in an incorrect perspective. As a result, it has decayed to the extent of meaning only identification of species. The symptoms of this decay have percolated from biologists to the teachers and even to students. The onus of identifying the plant or animal group invariably comes to the taxonomists. The names provided by them are taken on trust by the recipients without their ever having participated in the decision-making process. (Kubitzki, 1975).

Pollen Pistil Interaction-II

The pollen tubes after growing through the style reach the ovary and find their way into the ovules. The studies of pollen tube growth in many species have provided evidence in support of some chemotropic factors governing the pollen tube guidance. These studies have especially highlighted the role of the female gametophyte in pollen tube guidance. The role of embryo-sacs in the pollen tube guidance is clear from the studies on A. Thaliana where pollen tubes were guided only to those ovules with normal embryosacs and not to the ovules with degenerated embryo-sacs.

Herbarium

A herbarium (plural: herbaria) can be  defined as a repository of preserved plant collections, usually in the form of pressed and dried plant specimens,  mounted on specified sheets (thick paper sheets), identified and arranged according to  an approved and well-known system of classification. It also refers to the institution where dried plant specimens are maintained and studied, e. g. Kashmir University Herbarium (KASH). Herbaria are typically associated with universities, research institutions, botanical gardens, museums, or colleges.

Pollen-pistil interaction part

In flowering plants one of the most important steps in reproductive process is the pollination. Pollination in angiosperms is said to be indirect pollination since the pollen lands on stigma much away from the ovule which is well hidden and deep seated inside the ovary. Thus in angiosperms the pollen brings out a tube which runs through stigma, style and then ovary reaching to the inside of the ovule, rupturing and releasing the gametes there for bringing about fertilization successfully.

Pollination: its types & floral adaptations to them

In the seed plants (gymnosperms and angiosperms), the female gametophyte is fertilized by the male gametophyte in its own place inside the ovule or the megasporanginm. So it is obligatory that the male gamete, located inside the pollen grain, must be transferred from microsporangium or  male sporangium (pollen sac) to the megasporangium or the ovule. This transference of pollen from anther to the stigma is known as pollination (King and Brooks 1947). Types of pollination

Based on the destination of pollen grain, two types of pollination are mainly recognized:

ECONOMIC IMPORTANCE OF BACTERIA

Bacteria are a group of unicellular microscopic organisms which are having a prokaryotic organisation. They are found everywhere, in all habitats and ecosystems of biosphere. Bacteria are intimately associated with humans and other organisms of biosphere with both positive and negative interactions. These positive and negative relations of bacteria with the surrounding biotic and abiotic environment account for their beneficial and harmful roles in the economic development of humans.

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