Page 1 - 5. Structure of a flower
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SAI International School
                                              Subject- Biology, Class-VI
                                               Topic- The Plant World
                                          Subtopic- - Structure of a Flower

                                                     Lesson Notes

             The flower:

                   •  A flower develops from a bud. The flower further develops into a fruit which bears
                       seeds. Seeds when planted in the soil, under suitable conditions, can grow into a
                       new plant
                   •  The stalk of a flower is called the pedicel.

                   •  The swollen portion at the base of a flower is known as thalamus.

                       The various parts of a flower are:
                   •  Sepals- the outer most layer of a flower, which is protective in function. Sepals
                       protect the petals, stamens and the pistil in the bud condition.
                   •  Petals – They are bright and showy, of various shapes and sizes and brightly

                       coloured. They attract insects for pollination.
                   •  Stamens – This is the male reproductive part of the flower and consists of the anther
                       and the filament. The anther produces the pollen grains while the filament holds up
                       the anther.
                   •  Pistil- This is the female reproductive part of the flower and consists of the stigma,
                       style and the ovary.
                   •  Stigma – This is waxy or sticky to collect the dry pollen which is blown by the wind or
                       transferred by insects.

                   •  Style- It is a tube-like structure in which connects stigma and ovary. The pollen grains
                       travel through the style to reach the ovary
                   •  The ovary further develops into the fruit and the ovules into the seeds.


                       Pollination: It is the transfer of pollen grains from the anther to the stigma of a
                       flower.

                   •  Pollination can be self-pollination or cross pollination.
                   •  Self-pollination happens when the pollen grains are transferred from the anther of
                       one flower and reach the stigma of the same flower or another flower of the same
                       plant.
                   •  Cross pollination occurs when the pollen grains reach the stigma of a flower of the
                       same species on another plant.
                   •  Agents of pollination are insects, birds, wind and water.

                   •  Pollination results in the production of seeds.
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