6.3. SUMMARY

Anatomically, a plant is made of different kinds of tissues. The plant tissues are broadly classified into meristematic (apical, lateral and intercalary) and permanent (simple and complex).

Plants consist of various tissues that are responsible for different functions. These tissues can be categorized into two main groups:

1. Meristematic Tissues - These are undifferentiated tissues that can divide and give rise to new cells. They are located at the tips of roots and shoots (apical), along the sides of stems (lateral), and at the base of internodes (intercalary).
2. Permanent Tissues - These tissues have differentiated to perform specific functions. Permanent tissues are further divided into simple tissues (like parenchyma, collenchyma, and sclerenchyma) and complex tissues (like xylem and phloem). This classification helps us understand how plants grow and function.

Think of meristematic tissues as the 'youngsters' of a community who can learn and take on any role, while permanent tissues are like 'professionals' who have specialized jobs, such as doctors, teachers, and builders in our society.

Assimilation of food and its storage, transportation of water, minerals and photosynthates, and mechanical support are the main functions of tissues.

Plant tissues have key roles that ensure the plant's survival and growth:

• Assimilation and Storage: Some tissues are involved in the process of making food (photosynthesis) and storing it for later use.
• Transportation: Other tissues are responsible for moving essential resources like water and nutrients from the soil to other parts of the plant and moving food from areas where it is produced to areas where it is needed.
• Support: Certain tissues provide structural integrity, helping the plant to stand tall and maintain its form against environmental factors such as wind and gravity.

Imagine a community where some people grow food (assimilation), others transport it to markets (transportation), and some build the houses (support) – each group plays an essential role in the community’s overall function and health.

There are three types of tissue systems – epidermal, ground and vascular. The epidermal tissue systems are made of epidermal cells, stomata and the epidermal appendages. The ground tissue system forms the main bulk of the plant. It is divided into three zones – cortex, pericycle and pith. The vascular tissue system is formed by the xylem and phloem.

Plant tissues are organized into three main systems, each serving distinct functions:

• Epidermal Tissue System: This forms the outer protective layer of the plant, consisting of epidermal cells that may also have structures like stomata (pores for gas exchange) and appendages like hairs.
• Ground Tissue System: This constitutes the majority of a plant's structure and includes tissues like the cortex (storage and support), pericycle (a layer that can form new roots), and pith (storage and nutrient transport).
• Vascular Tissue System: This system includes two main types of conducting tissues: xylem, which transports water and minerals from roots to leaves, and phloem, which carries nutrients produced by photosynthesis throughout the plant.

You can think of the plant as a city. The epidermal layer is like the city walls protecting it, the ground tissue is the residential area where people live, and the vascular systems are like the roads that keep everything connected, allowing goods and people to move around effectively.

Monocotyledonous and dicotyledonous plants show marked variation in their internal structures. They differ in type, number and location of vascular bundles. The secondary growth occurs in most of the dicotyledonous roots and stems.

Plants are categorized into two main groups based on their internal structures:

• Monocots: These plants typically have vascular bundles that are scattered and do not show secondary growth. Examples include grasses and lilies.
• Dicots: In contrast, dicotyledonous plants have vascular bundles arranged in a ring and often undergo secondary growth, allowing them to grow thicker over time, like trees and shrubs. The variations in vascular arrangement affect how these plants grow and their overall structure.

Imagine two types of buildings in a city: Monocots are like apartments without basements (no secondary growth), while Dicots are like multi-story buildings with basements that can be expanded later (secondary growth), showcasing how different designs serve various functions.

--