Unit 3 Plant Families Topic Solanaceae B Ed

Unit 3: Plant Families Topic: Solanaceae B. Ed (Hons) Secondary Semester III Subject: Advance Biology I Course Title: Plant Systematics and Anatomy Represented By: Ms Sidra Younis Department of Education (Planning and Development) Lahore College for Women University, Lahore

INTRODUCTION Ø Ø The nightshade, or potato, family of flowering plants (order Solanales), with 102 genera and nearly 2, 500 species, many of considerable economic importance as food and drug plants. Among the most important of those are potato (Solanum tuberosum). Solanaceae are mostly herbs, shrubs, or woody epiphytes, although there are some trees in the family. The family includes major crop plants such as potatoes, tomatoes, bell peppers, eggplants and tobacco etc.

DISTRIBUTION OF SOLANACEAE: The family is commonly called ‘Potato family’. It is a large family well distributed in tropics and sub-tropics, though a few members are found in temperate zone. Members of the Solanaceae are found on all continents, the greatest variety of species are found in Central America and South America. Centers of diversity also occur in Australia and Africa. Solanaceae occupy a great number of different ecosystem, from desert to rainforest, and are often found in the secondary vegetation that colonizes disturbed areas. In general, plants in this family are of tropical and temperate distribution.

MORPHOLOGY: Plants in the Solanaceae can take the form of herbs, shrubs, trees, vines and lianas, and sometimes epiphytes. They can be annuals, biennials, or perennials. Root (rhizoms): Solanaceae members have branched tap root system, plants produce rhizomes (often called stolons). They originate from the basal stem nodes, typically below ground, with up to three rhizomes per node. Further from here several structures originated. It actually helps to anchor the tubers underground. Stem: Aerial, erect, climbing herbaceous, or woody, cylindrical, branched, solid or hollow, hairy, or glabrous, underground stem in Solanum tuberosum. Leaf: The leaves are generally alternate. The leaves can be herbaceous, leathery, or transformed into spines. The leaves are generally petiolate or subsessile, rarely sessile. The leaves have reticulated venation. The stomata are generally confined to one of a leaf's two sides; they are rarely found on both sides.

Floral Characters: Inflorescence: Solitary axillary, umbellate cyme, or helicoid cyme in Solanum. Flower: Bracteate or ebracteate, pedicellate, complete, hermaphrodite, actinomorphic, pentamerous, hypogynous. Calyx: Sepals 5, gamosepalous, tubular or campanulate, valvate or imbricate, persistent, green or coloured, hairy, inferior. Corolla: Petals 5, gamopetalous, tubular or infundibuliform, valvate or imbricate aestivation, scale or hair-like outgrowth may arise from the throat of the corolla tube, coloured, inferior.

Androecium: Stamens 5, epipetalous, polyandrous, alternipetalous, filaments inserted deep in the corolla tube, anthers dithecous, usually basifixed or dorsifixed, introrse, inferior. Gynoecium: Bicarpellary, syncarpous, ovary superior, bilocular, axile placentation placentae swollen, many ovules in each loculus, ovary obliquely placed; in some cases nectariferous disc is present; style simple; stigma bifid or capitate. Fruit: A capsule or beery. Seed: Endospermic. Pollination: Entomophilous. Floral Formula:

IMPORTANT GENERA: The important Genra of this family are following: Solanum melongena (egg plant) Solanum tuberosum (potato) Capsicum annum (green pepper) Lycopersicum esculentum (tomato) ECONOMIC IMPORTANCE: The economic importance of this family is following: In vegetables: Solanum tuberose, melongena, Capsicum annum, Lycopersicum esculentum etc. are used as vegetables. In tobacco products: Nicotine tobaccum leaves and stem are used for preparing cigarettes and tobacco products.

Medicinal value: Roots of Atropa belladonna yield a powerful alkaloid ‘atropine’ which is used in tinctures, plasters and relieving pain. It is also used for dilating pupils of eyes during eye treatment. Dried leaves and roots of Datura metel is used for the treatment of asthma. In the formation of cheese: Withania somnifera can coagulate milk for making cheese. Ornamental value: Petunia hybrida, Solanum villosum have ornamental value.