Linggo, Oktubre 2, 2016

Jessa Abad
Jennelyn Galgo
Angeline Icaro
Agnes Escario
Carlito Saulon Jr.
Dorina Araojo
Joyce Cardano

ProfEd. 7b (M.W. 7:00-8:30 A.M.)

F l o w e r

              Flower is a component of the shoot system and is the characteristic feature of angiosperms. Flower is responsible for the development of seed. It is the plant's reproductive structure. Sexual reproduction in plants is enabled by flowers and it is the sign of plants survival. 

              Flower is also known as bloom or blossom. The main biological function of flower is reproduction; the flowers provide a mechanism for the union of sperm with eggs. Flowers produce seeds and fruits. Many flowers are attractive to animals and attract vectors for the transfer of pollen grain. 

Flower is a highly specialized shoot and is modified and ceased to grow to house the reproductive structures. They are usually bright colored to attract insects for pollination.  Flowers that are not colorful are pollinated by wind. All flowers have the basic plan having four main parts: sepals, petals, stamens and carpels. They are usually both male and female. The stamen is the male part of the plant and carpel is the female part of the plant. 


Flower Definition


Flowers are the reproductive organs of plants. Flower is the modified vegetative shoot and is meant for sexual reproduction. Flower arises from a modified leaf called bract. It consists of a very short axis on which whorls of different parts of the flower are present.




Peduncle

A stalk supporting an inflorescence, which is the part of the shoot of seed plants where flowers are formed in the flower.



Receptacle


Receptacle is the stem portion, it is found at the base in the center of the flower. The internodes are short and the number of leaves is small. Hence, receptacle is not usually a large part of the flower. 




Sepals 

Sepals form the outermost whorl of the floral structure. They are mostly but not always green and are leaf-like in appearance. Sepals are similar to the foliage leaves of the plant. Sepals are collectively known as the Calyx. The major function of the calyx is the protection of flower parts during early development of the flower or the bud. 



Petals

Petals are present above the sepals whorl. Petals are larger than the sepals, they are brightly colored, leaf-like, broad and are thin organs. The petals collectively are known as the Corolla. Corolla is the attractive part of the flower. They provide additional protection and attract insects to facilitate pollination of the flower. 
The leaf-like organs, the sepals and the petals are together known as the perianth of the flower. They are similar in appearance.

Carpels

Carpels are one or more in number and are located in the upper center of the flower. Collectively the carpels are known as gynoecium. Carpels are made of three parts: Ovary. Style and Stigma.

1.   Ovary is the structure present at the base of the carpel. It is an enlarged narrow region bearing one or more ovules.
2.   Style is the slender, neck-like portion of the carpel the leads to the ovary. 
 3.   Stigma is of variety of shapes and sizes. It present at the tip of the carpel and is sticky to collect pollen grains.



Stamens

Stamens are located inside the corolla and are leaf-like appearance. Stamens are the male part of the flower and produces pollen. Stamens consists of a filament and an anther. Stamens are collectively called androecium. 


Anther is the sac located at the tip of the filament that contains pollen.
Filament is the stalk that connects to and holds up the anther. 
Nectaries are often associated with flowers and are found at the receptacle, nectaries produce sugary nectar which attracts insects. 














Bract

Flower consists of a stalk and is called pedicel. The flower is described as sessile if the pedicel is absent. Flowers are known as ebracteate in the absence of bracts. Bract-like green structures are present on the pedicel and are called bracteoles and the flower with presence of bractiole is called bracteolate and absence of bracteoles is described as ebracteolate

Bracts are of various types:
   
1.   Foliaceous: Leaf-like bracts as in Adhantoda.
2.   Petaloid: Petal like bracts, peatloids is bracts where they are large and colored as in Bougainvillea.
3.   Involucre of bracts: Here many bracts form one or more whorled structures called involucres. Example: Head inflorescence of Helianthus.

Calyx

Sepals are collectively known as calyx. It forms the outermost whorl of a flower. They are usually green in color and their typical function is protection for the flower in bud stage and also supports the petals when in bloom. Morphologically sepals are modified leaves. 






Corolla


Corolla makes up the second whorl of the flower and it is composed of petals. They are brightly colored, making the corolla conspicuous, and attractive. Petals are also scented in many cases. They help attracting insects for pollination. 


Pistil


Pistil is the female reproductive part of a flower. It is located centrally and consists of a swollen base, which is the ovary. The ovary contains the ovules which are the potential seeds; a stalk or style and a stigma which the pollen receptive tip. Pistil in collective sense forms the gynoecium. 


Pistil is the word used to describe each unit of the gynoecium. A pistil consist of a single carpel which can be a monocarpous or apocarpus gynoecium, in which case it is called a simple pistil. It also may be of fused carpels or a syncarpous gynoecium and is called a compound pistil.


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