MICROSPOROGENESIS IN ANGIOSPERM
Microsporogenesis The process of formation of microspore or pollen grain within the pollen sac of anther is known as microsporogenesis. Stamen is the male fertilizing organ of flower. It typicall...
Family- Cruciferae
The family includes about 375 genera and 3200 species. The family is also called Brassicaceae.
Distribution: Most of the members of this family are cosmopolitan in distribution. They are mainly found in the temperate region and also in the subarctic region. They are widely cultivated for vegetables, oilseeds and also as ornamental plants.
Habit: Mostly they are annual, biennial or perennial herbs. A few are smaller shrubs. They have sulfur smelling pungent sap that contains glucosides.
Root: taproot and branched
Stem: Erect or herbaceous, branched or unbranched, hairy, cylindrical, initially reduced but elongates after the vegetative growth ( Raphanus sativus) and forms the floral shoot. The main stem is very much condensed and corm like as in (Brassica rapa).
Leaf: Radical, cauline and Ramal, alternate opposite petiolate or sessile, lyrate, hairy, sheathing leaf base, acute apex, upper leaf entire and sessile, exstipulate, unicostate, reticulate venation.
Inflorescence: racemose generally raceme or corymbose.
Flower: Ebracteate, pedicellate, actinomorphic rarely zygomorphic(Iberis), diplochlamydous, bisexual, polycyclic, regular, complete, tetramerous, cruciform, hypogynous, perigynous in lepidium
Calyx: Sepals 4, gamosepalous, arranged in 2 whorls of 2+2, anterio posterior petaloid, imbricate aestivation, inferior
Corolla: Petals 4, gamopetalous, cruciform corolla( each petal differentiated into a narrow claw and broadly expanded limb) alternating with sepals, petals are reduced in Coronopus.
Androecium: stamens 6, polyandrous, arranged in two whorls of 2+4 tetradynamous, outer whorls of two short stamens and inner whorls of four short stamens, green nectaries at the base of two short stamens, anther dithecous, basifixed introrse,
Gynoecium: Bicarpellary, syncarpous, ovary superior, unilocular in early-stage later bilocular due to the development of false septum known as replum, parietal placentation, style short, stigma capitate.
Fruit: siliqua or silicula or lomentum like a siliqua
Pollination: Usually entomophilous, cross or self-fertilization
Some of the member plants of this family are: