Anatomy of Flowering Plants
Habish Ribin Haneef
Flowers, one of the most beautiful things in this world, right? People who do not love flowers’ beauty and fragrance may be rare. But have you ever imagined what these exquisite things constitute? The internal structure of flowering plants is a world of vast and enormous features. Anatomy is the study of the internal structure of organisms. The anatomy of flowering plants comprises of organization and structure of tissues. So, to know the anatomy of flowering plants, first of all, you need to know what tissue is. In this blog, let’s briefly discuss the anatomy of flowering plants.
The Tissue:
The term tissue refers to a group of cells that share a common origin and usually perform the same function. Tissues are classified into two- Meristematic Tissue and Permanent Tissue.
The meristematic tissue is made up of a group of similar and immature cells that have the capability to divide and form new cells. Meristematic tissue is again classified into three- apical meristem, intercalary meristem, and lateral meristem. Apical meristem is the primary meristem. The apical meristem occurs at the tips of roots and shoots. It increases the length of the plant. The intercalary meristem is the meristem that develops between regions of mature or permanent tissues, especially in grasses. The intercalary meristem is capable of forming branches and flowers. Both the apical meristem and intercalary meristem are primary meristems. The lateral meristem is the secondary meristem and is responsible for the secondary growth of the plant. The lateral meristem occurs in the mature regions of roots and shoots. The primary lateral meristem is the intrafascicular cambium and the secondary lateral meristems are the vascular cambium and cork cambium.
The permanent tissue is made up of structurally and functionally specialized cells which have lost the ability to divide. These tissues are derived from meristematic tissues. The permanent tissue is classified into two- simple permanent tissue and complex tissue. Simple permanent tissues are those tissues having all the cells similar in structure and function. On the other hand, complex tissues are those tissues having different kinds of cells. Simple permanent tissues are again divided into three- parenchyma, collenchyma, and sclerenchyma. Parenchyma is made up of thin-walled isodiametric cells. Their cell wall is made up of cellulose. In each cell, there is a large central vacuole and a peripheral cytoplasm containing a nucleus. Parenchyma is found in soft and non-woody areas of roots, stems, leaves, flowers, and fruits. The functions of parenchyma include photosynthesis, storage, and secretion. Collenchyma is made up of living, closely packed isodiametric cells. Collenchyma consists of thickened cells at the corner. This thickening is due to cellulose, hemicellulose, and pectin. It is the collenchyma that provides mechanical support to the growing parts of the plant such as young stem. Sclerenchyma is made up of dead cells with thick and lignified walls. Sclerenchyma are of two types- fibres and sclereids. Like collenchyma, sclerenchyma too provide mechanical support but it provides mechanical support to the mature plant organs.
Complex tissues are again divided into two- xylem and phloem. Xylem is made up of tracheids, vessels, xylem fibre, and xylem parenchyma. Xylem conducts water and minerals from roots to other parts of the plant. Xylem is found deep in the plant and it provides mechanical strength. Phloem is made up of sieve tube, companion cells, phloem parenchyma, and phloem fibres. Phloem transports food materials from leaves to various parts of the plant. Phloem is found towards the outer side.