An ovule (megasporangium) may arise from the placenta at the base of the ovary or on the inner surface of the ovary. It is borne on a distinct stalk, the funicle which is attached to the body of the ovule at a point called the hilum. The central and somewhat conical part of the ovule is the nucellus. It consists of a mass of parenchymatous cells. It represents the metasporangium proper and is invested by two-layered integuments in monocotyledons and primitive dicotyledons (Archicliamydeae) but by single-layered integument in the higher dicotyledonous families (metachlamydeae); very rarely unitegmic and bitegmic ovules occur in the same family. In many cases, single integument has resulted due to the fusion of two separate primordials or by elimination of one of the two integuments. The third integument in the form or aril is found in plants like Asphodehus and Trianthema, while Ricinus and several other plants of the family, Euphorbiaceae, show an integumentary proliferation calle...
BIFACIAL LEAF: It is also called dorsiventral leaf. This leaf is more strongly illuminated on upper surface than on lower surface. This unequal illumination induces a difference in the internal structure between upper and lower sides. Its internal structure shows: (1) Upper Epidermis This is single layer of cells with thick cuticle which checks excessive evaporation of water from the surface. It does not contains chloroplasts, stomata are also absent. (2) Lower Epidermis This is also single layer but with a thin cuticle. It bears many stomata, two guard cells of which contain some chloroplast, none are present in the epidermal cells. Internal to each stomata is large cavity called respiratory cavity. Lower epidermis of leaf is meant for exchange of gases (oxygen and carbon dioxide) between the atmosphere and the plant body. Excess water also evaporates from lower epidermis. (3)...
Introduction Some, literature can be satisfactorily read and discussed taking the author into account. Other literature seems inseparable from the person who created it. To an extraordinary degree Hemingway and what he has written exist in a synergetic relationship, reinforcing and fulfilling each other; he has created a personal legend which serves as an ambience in which we read him. Autobiographical Touches The novel A Farewell to Arms autobiographical elements. The love-affair between Fredric and Barkley, the hero’s injury in the battlefield, his despair and frustration, the hero’s separate peace with life are some of the characteristics of Hemingway’s life. Hemingway himself had received the injury caused by the mortar-shell at Fossalta, and he was admitted into the Milan hospital for recuperation in the late summer and autumn of 1918. He fell in love with the nurse in the Milan hospital. Carlos Baker has thrown light on this fact. In A Farewell to Arms Hemingway was d...
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