Anatomy of Flowering Plants PDF Free Download
Chapter 6: Anatomy of Flowering Plants
You can very easily see the structural similarities and variations in the external morphology of the larger living organism, both plants, and animals.
Similarly, if we were to study the internal structure, one also finds several similarities as well as differences.
This chapter introduces you to the internal structure and functional organization of higher plants.
The study of the internal structure of plants is called anatomy. Plants have cells as the basic unit, cells are organized into tissues and in turn, the tissues are organized into organs.
Different organs in a plant show differences in their internal structure.
Within angiosperms, the monocots and dicots are also seen to be anatomically different. Internal structures also show adaptations to diverse environments.
6.1 The Tissue
A tissue is a group of cells having a common origin and usually performing a common function. A plant is made up of different kinds of tissues.
Tissues are classified into two main groups, namely, meristematic and permanent tissues based on whether the cells being formed are capable of dividing or not.
6.1.1 Meristematic Tissues
Growth in plants is largely restricted to specialized regions of active cell division called meristems (Gk. meristos: divided).
Plants have different kinds of meristems. The meristems which occur at the tips of roots and shoots and produce primary tissues are called apical meristems.
Root apical meristem occupies the tip of a root while the shoot apical meristem occupies the distant most region of the stem axis.
During the formation of leaves and elongation of the stem, some cells ‘left behind’ from shoot apical meristem, constitute the axillary bud.
Such buds are present in the axils of leaves and are capable of forming a branch or a flower.
The meristem which occurs between mature tissues is known as intercalary meristem. They occur in grasses and regenerate parts removed by the grazing herbivores.
Both apical meristems and intercalary meristems are primary meristems because they appear early in the life of a plant and contribute to the formation of the primary plant body.
The meristem that occurs in the mature regions of roots and shoots of many plants, particularly those that produce woody axis and appear later than primary meristem is called the secondary or lateral meristem.
They are cylindrical meristems. Fascicular vascular cambium, interfascicular cambium and cork-cambium are examples of lateral meristems.
These are responsible for producing secondary tissues.
Following divisions of cells in both primary and as well as secondary meristems, the newly formed cells become structurally and functionally specialized and lose the ability to divide.
Such cells are termed permanent or mature cells and constitute permanent tissues. During the
formation of the primary plant body, specific regions of the apical meristem produces dermal tissues, ground tissues, and vascular tissues.
6.1.2 Permanent Tissues
The cells of the permanent tissues do not generally divide further. Permanent tissues having all cells similar in structure and function are called simple tissues. Permanent tissues having many different types of cells are called complex tissues.
| Author | – |
| Language | English |
| No. of Pages | 16 |
| PDF Size | 3.5 MB |
| Category | Biology |
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Anatomy of Flowering Plants PDF Free Download