PISTIL- THE FEMALE REPRODUCTIVE ORGAN

                                     

STD-12      UNIT-6     CHA-2

REPRODUCTION IN FLOWERING PLANT

PISTIL- THE FEMALE REPRODUCTIVE ORGAN 

• Gynoecium represents the female com ponent of a flower . 
• It may consist of only one carpel ( monocarpellary ) , two carpels ( bicarpellary ) , three carpels ( tricarpellary ) or many carpels ( multicarpellary ) . 
• Each carpel represents a megasporophyll . 
• Gynoecium is apocarpous ( Gk apo- away or separate , karpos- fruit ) 
• if the carpels are free , e.g .. Michelia , Ranunculus . 
• It is syncarpous ( Gk syn - with , karpos - fruit ) 
• if carpels are fused , e.g. , Hibiscus , Papaver ( Poppy ) . 
• The basal parts of carpels must fuse for syncarpous condition . 
• Parts of styles and stigmas can be free , e.g. , Hibiscus . 
• In apocarpous condi tion , the ovaries must be free , though other parts may get fused , e.g. , Oleander .

• The free unit of gynoecium is called pistil .
• A pistil has three parts - stigma , style and ovary . 

• Stigma is the terminal receptive part of the pistil which functions as landing platform for the pollen grains . 
• It also determines the compatibility - incompatibility of the pollen grains . 
• Style is elongated narrow stalk that connects the ovary with the stigma 
• Ovary is the basal swollen part of the pistil . 
• It has an ovarian cavity with one or more chambers or locules and ovule bearing parenchymatous cushions called placentae ( singular placenta ) . 
• An ovary may have one ( c.8 .. Wheat , Paddy , Mango ) to several ovules ( e.g. , Papaya . Water Melon . Orchids ) .

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