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In this article we will discuss about:- 1. Characters of Solanaceae 2. Distribution of Solanaceae 3. Economic Importance 4. Affinities 5. Important Types.
Characters of Solanaceae:
Plants herbs, shurbs rarely trees; leaves alternate, flowers solitary or in cymes; axillary or terminal; flowers pentamerous, actinomorphic, hypogynous, hermaphrodite, calyx persistent, gamosepalous, corolla gamopetalous, campanulate; stamens epipetalous; gynoecium bicarpellary, syncarpous, ovary obliquely placed, axile placentation; swollen placentae; ovules many in each locules; fruit capsule or berry.
A. Vegetative characters:
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Habit:
Mostly herbs (Petunia, Withania), shrubs and trees.
Root:
A branched tap root system.
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Stem:
Aerial, erect, climbing (Solanum jasminoides), herbaceous, or woody, cylindrical, branched, solid or hollow, hairy, or glabrous, underground stem in Solanum tuberosum.
Leaves:
Cauline, ramal, exstipulate, petiolate or sessile, alternate sometimes opposite, simple, entire pinnatisect in Lycopersicurn, unicostate reticulate venation.
B. Floral Characters:
Inflorescence:
Solitary axillary, umbellate cyme, or helicoid cyme in Solanum.
Flower:
Bracteate or ebracteate, pedicellate, complete, hermaphrodite, actinomorphic, pentamerous, hypogynous.
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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.
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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, unilocular in Henoonia, 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.
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Fruit:
A capsule or beery.
Seed:
Endospermic.
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Pollination:
Entomophilous.
Floral formula:
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. The family includes 2,000 species belonging to 90 genera. In India it is represented by 70 species of 21 genera.
Several members are cultivated through out the world for their great economic importance; among them are Solarium tuberosum (Potato), Solarium melongena (Bringal), Lycopersicurn esculentum (Tomato) etc.
Economic Importance of Solanaceae:
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The family is of great economic importance.
1. Food:
Many members viz., Solanum tuberosum (Potato), Solanum melongena (Brinjal), Lycopersicurn esculentum (Tomato), Capsicum (H. Mirch) etc. are used as vegetables. Physalis peruviana (H. Rasbhari) produces edible berries.
2. Medicinal:
Atropa belladona contains alkaloid Atropine; this is used in Belladona plaster. Atropine is used in eye testing. Nicotiana tabacum (tobacco) yields Nicotine. Hyoscyamus niger, Solanum nigrum, Datura (H. Dhatura), Withania somnifera (Ashwagandha) are used medicinally.
3. Narcotics:
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Tobacco is obtained from leaves of Nicotiana tabacum and variously used in cigars, bidi, chewing, jarda etc.
4. Ornamentals:
Petunia, Cestrum, Lycium, Salpiglossis, Schizanthus are cultivated in gardens for ornamentals.
Primitive characters:
1. Shrubs, trees and perennial climbers.
2. Leaves simple and alternate.
3. Inflorescence solitary axillary or terminal.
4. Flowers actinomorphic, hermaphrodite and hypogynous.
5. Pollination by insects.
6. Ovules numerous in each loculus.
7. Stamens dithecous.
8. Seeds endospermic.
Advanced characters:
1. Most of the plants are herbaceous and many are annuals.
2. Leaves exstipulate, in some finely divided.
3. Calyx and corolla are gamosepalous and gamopetalous.
4. Stamens epipetalous.
5. Reduction in the number of carpels to two.
6. Gynoecium is syncarpous.
7. Fruit is simple.
Affinities of Solanaceae:
Hallier regarded Solanaceae as a primitive member of the tubiflorae together with the Scrophulariaceae and both have arisen very likely from the Linaceae. Wettstein placed the family in the Tubiflorae along with Convolvulaceae. Rendle placed the family in the Tubiflorae, assigning a separate position for the Convolvulaceae under the order Convolvulales.
Solanaceae bears a close relationship to the Boraginaceae in alternate leaves, regular flowers and five stamens. It is related to Convolvulaceae in the presence of persistent calyx, twisted corolla and false septum. It is allied to Scrophulariceae but the latter differs from it in actinomorphic flowers and obliquely placed carpels.
Common plants of the family:
1. Browallia:
An ornamental genus characterised by the presence of 4 didynamous stamens.
2. Cestrum nocturnum (H. Rat Ki Rani or Queen of the night):
A garden plant with flowers emitting sweet smell at night.
3. Datura metal (H. Dhatura or Thorn apple):
A herb with highly poisonous fruits and seeds.
4. Petunia:
A garden ornamental.
5. Lycoperscium esculentum:
A tall herb with red globose pulpy fruits.
6. Physalis peruviana:
Produces edible reddish berries that are enclosed in a bladdery and persistent calyx.
7. Solanum nigrum (H. Mako):
A roadside herb S. xanthocarpum a spinous xerophytic herb.
8. Withania somnifera (H. Asgandh, Sanskrit – Ashwangandha):
A perennial tall herb.
Division of the family and chief genera:
Von Wettstein divided the family in to five tribes and two groups:
A. Embryo curved like a semicircle,.stamens 5, filaments equal.
Tribe 1. Nicandreae:
Gynoecium bicarpellary with 3-5 locules e.g. Nicandra.
Tribe 2. Solaneae:
Ovary bilocular; e.g. Solanum, Capsicum.
Tribe 3. Datureae:
Ovary 4-celled, septum dividing placenta equally; e.g. Datura.
B. All stamens or 2-4 stamens fertile; embryo slightly or almost straight.
Tribe 4. Cestreae:
All 5 fertile stamens; seeds not flat; e.g. Cestrum.
Tribe 5. Salpiglossideae:
Stamens 2-4 fertile; flowers zygomorphic; e.g. Browallia, Salpiglossis.
Important Types of Solanaceae:
1. Solanum nigrum (Fig. 78.1):
Habit:
A wild herb.
Root:
Branched tap root system.
Stem:
Erect, aerial, woody below and herbaceous above, cylindrical with distinct ribs, solid, branched, green.
Leaves:
Alternate, simple, exstipulate, petiolate, ovate, repand, acute, glabrous, unicostate reticulate venation.
Inflorescence:
Extra-axillary helicoid cymes. Extra axillary position is due to fusion.
Flower:
Ebracteate; pedicellate, complete, hermaphrodite, actinomorphic, pentamerous, hypogynous, small and white.
Calyx:
Sepals 5, gamosepalous, pentafid, valvate, persistent, green, hairy, inferior.
Corolla:
Petals 5, gamopetalous, rotate, valvate, five lobed, white, inferior.
Androecium:
Stamens 5, polyandrous epipetalous, alternipetalous, filaments shorts, equal in length, anthers long and conniving, basifixed, dithecous, and dehiscence by apical pores.
Gynoecium:
Bicarpellary, syncarpous, ovary superior, bilocular, axile placentation, placentae swollen, ovules many in each loculus, ovary obliquely placed; style simple, hairy; stigma bilobed.
Fruit:
A berry.
Seed:
Endospermic.
Floral formula:
2. Withania somnifera (Fig. 78.2):
Habit:
Wild perennial herb.
Root:
Branched, tap root system.
Stem:
Erect, aerial, cylindrical, solid, woody below and herbaceous above, branched, covered with hair.
Leaves:
Cauline, ramal, opposite, simple, exstipulate, petiolate ovate, entire, acute, covered with glandular branched hair, unicostate reticulate venation.
Inflorescence:
Axillary cyme.
Flower:
Ebracteate, sub-sessile, complete, hermaphrodite, actinomorphic, pentamerous, hypogynous.
Calyx:
Sepals 5, gamosepalous, campanulate, pentafid, valvate, hairy, green, inferior.
Corolla:
Petals 5, gamopetalous, pentafid, campanulate, valvate aestivation, corolla lobes inflexed, greenish yellow.
Androecium:
Stamens 5, polyandrous, epipetalous, alternipetalous inserted near the base of corolla tube, filaments equal in length; basifixed, dithecous, introrse.
Gynoecium:
Bicarpellary, syncarpous, ovary superior, bilocular, ovules many, axile placentation, placentae swollen, ovary obliquely placed; hairy, style simple; stigma bifid.
Fruit:
A berry enveloped by persistent calyx.
Seed:
Endospermic.
Floral formula:
3. Datura metel:
Habit:
An annual herb.
Root:
Tap, branched, annual.
Stem:
Herbaceous, erect, cylindrical, branched, slightly woody and slightly fistular, hairy.
Leaf:
Alternate, opposite in floral region, simple, exstipulate, petiolate, ovate-lanceolate, acuminate or acute apex, unequal at base, sinuate-toothed or repand margin, glabrous on both sides, unicostate reticulate venation.
Inflorescence:
Solitary axillary.
Flower:
Shortly pedicellate, bracteate, hermaphrodite, actinomorphic, complete, hypogynous, pentamerous.
Calyx:
Sepals 5, gamosepalous, tubular, angulate, 5-toothed, teeth triangular lanceolate, acuminate, green, persistent, twisted aestivation, inferior.
Corolla:
Petals 5, gamosepalous, campanulate, 5 or 6 cuspidate acute angles, violet outside, twisted aestivation, inferior.
Androecium:
Stamens 5, epipetalous, filaments long, anthers basifixed, introrse, dithecous.
Gynoecium:
Bicarpellary, syncarpous, ovary superior, obliquely placed, four celled due to the formation of false septum, axile placentation, many ovules in each loculus, style long, stigma bilobed.
Floral formula:
4. Petunia alba (Fig. 78.3):
Habit:
A cultivated annual herb.
Root:
Tap, branched.
Stem:
Herbaceous, erect, cylindrical, solid, branched, hairy, green.
Leaf:
Cauline, simple opposite decussate, exstipulate, ovate, unicostate reticulate venation.
Inflorescence:
Axillary or terminal condensed cymes.
Flower:
Pedicellate, bracteate, hermaphrodite, complete, actinomorphic, pentamerous, hypogynous.
Calyx:
Sepals 5, gamosepalous, campanulate, sepals free above and fused below, green, hairy, imbricate aestivation, inferior.
Corolla:
Petals 5, gamopetalous, campanulate, tube hairy, twisted aestivation, inferior.
Androecium:
Stamens 5, polyandrous, epipetalous, alternating with the petals, filaments long, anthers basifixed, dithecous, introrse.
Gynoecium:
Bicarpellary, syncarpous, ovary superior, obliquely placed, bilocular; swollen axile placentation; ovules many; style long, slightly, twisted, stigma capitate, bilobed.
Floral formula:
