Flower is a modified shoot that is specialized for sexual reproduction. Flower originates from floral buds. Flower is colorful structure which associates with angiosperms( flowering plant). Flowers are attracted by the insects used for sexual reproduction. In angiosperm, the reproductive structure is colorful and it includes sepals, petals and stamen etc. The plants that bear flowers are usually smaller in size and lack of wood
Flower:
flower is a shoot that is modified for reproductive function or A modified reproductive shoot is called flower.
Parts of flower:
The structure or parts of flower are divided as follows:
- reproductive part
- nonreproductive part
Reproductive:
The reproductive part of flower is divided into
- Androecium
- Gynoecium
1-Androecium:
It is the male reproductive organ of the flower.
The male reproductive part of flower are also known as stamens (Many stamens are known as androecium). Staminode are sterile stamens. When stamens are present inside the flower, they may be united or free.
- The free stamens are called polyandrous.
- If the stamens are united in one bunch, then they are called monoadelphous.
- If they are united in more than one bunches then they are called polyadelphous.
- If they are united in two bunches, then they are called diadelphous.
- If stamens get attach to petals, then they are called epipetalous.
- If they attach to perianth, then they are called epiphyllous.
Androecium is further divided into:
- Anther
- Filament/stalk
Anther:
The anther is bilobed in structure and each lobe consist of two chambers which called as pollen sacs. Pollen grains are produces inside pollen sacs. It is the head of stamen.
Filament/stalk:
The long and cylindrical part of flower is known as filament. it attaches anther to the flower.
2-Gynoecium:
It represents the female reproductive organ of the flower
It consist of one or more carples
It is further divided into:
- stigma
- style
- ovary
style:
Style is present at the center and it connect ovary and stigma.
stigma:
It act as receptive surface of pollen grains.
ovary
After the process of fertilization, the ovules develop into seed and ovary are develop into fruit.
Inside the ovary, ovules are present. Ovules are attached to flattened cushion like structure called placenta. Two or more than two ovule are present in ovary.
- If carples are free, then they are called apocarpoles (lotus/ rose)
- if carples are united in flower, then they are called syncarples.
Non reproductive:
The non reproductive part of flower is divided into
- Calyx
- Corolla
1-Calyx:
- It is the outermost covering of flower.
- It has usually leaf like structure.
- Calyx have green leaves it.
- It also provide protection to the flower during bud stage.
The members of calyx are commonly called as sepals which are green in color and protect flower during bud stage.
2-Corolla:
- corolla have colored leaves.
- It attracts insect for pollination.
The members of corolla are called as petals. These are brightly colored because to attracts the insects for pollination. These are varies in shape and sizes from plants to plants
i.e. tubular shape, bell shape etc.
Aestivation:
Aestivation is the arrangement of sepals or petals in a floral bud.
The arrangements may be:
- valvate aestivation
- twisted aestivation
- imbricate aestivation
- vexillary aestivation
valvate aestivation: (calatropis)
In valvate aestivation, the margins touch each other instead of overlapping.
twisted aestivation: (china rose)
In twisted aestivation, the margins overlap each other rather than touch.
imbricate aestivation:(gulmohar)
In imbricate aestivation, the margins overlap each other but not in regular manner.
Vexillary aestivation:
The petals are always 5 in number.
The overlapping in a manner that the larger petal overlap than the smaller and so on.
Functions of flower:
The flower has following functions
- It involves in sexual reproduction
- It involves n pollination or fertilization
- It involves in fruit formation
- It involves in dispersal of seed or fruit
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