Question

Development in plants is mainly controlled by (a) Intrinsic factor (b) Extrinsic factor (c) Both (a) and (b) (d) None of these

Short answer

The correct answer is (c) Both (a) and (b) as both intrinsic and extrinsic factors primarily control plant development.

Step-by-step solution

Understanding the Factors

Intrinsic factors refer to the internal genetic control and developmental mechanisms within the plant, such as cell division, cell elongation and differentiation. These control plant's size, shape, and other internal characteristics. Extrinsic factors refer to the external environmental control such as sunlight, temperature, water, nutrients, and other ecological factors. These influence the plant's growth, survival, and adaptation.

Combining the Factors

A combination of both intrinsic and extrinsic factors primarily control plant development. On one hand, a plant’s intrinsic factor namely its genetic constitution decides its potential for growth and development. On the other hand, the plant’s adaptation, survival, and even the expression of its genetic potential is influenced by the extrinsic factors. For instance, a plant might have the genetic potential to grow tall, but lack of sunlight (an extrinsic factor) might stunt its growth.

Arriving at the Answer

By combining the understanding from the two preceding steps, it can be concluded that both intrinsic and extrinsic factors play crucial roles in plant development. Thus, the correct answer is (c) Both (a) and (b).

Key concepts

Intrinsic Factors

Intrinsic factors are the internal drivers of plant development. Imagine these as the plans and blueprints that guide a plant through its life cycle. These factors are fundamentally genetic and involve processes like cell division, cell elongation, and differentiation. Intrinsic factors shape the plant’s internal structure and determine core aspects such as size and shape.
The intrinsic factors operate much like an instruction manual coded within the plant's DNA.

• The growth potential is set by these genetic scripts.
• They ensure the plant has the necessary tools to grow, reproduce, and survive.
• Even specific traits, like leaf shape or flower color, are dictated by intrinsic genetic information.

Understanding the intrinsic factors allows us to appreciate how plants maintain a regulated structure while adapting to varying external conditions.

Extrinsic Factors

Extrinsic factors are the external elements surrounding the plant that influence its development. Picture these factors as the environment in which the plant grows, which can either support or challenge its growth. While intrinsic factors set the potential, extrinsic factors determine how and to what extent that potential is expressed.
Key examples of extrinsic factors include:

• Sunlight: Essential for photosynthesis, affecting energy production and growth.
• Temperature: Influences metabolic rates and developmental rhythms.
• Water: Vital for nutrient transport and cellular processes.
• Soil Nutrients: Necessary for building plant tissues and overall health.

The extent to which a plant thrives or struggles in its environment often depends on how effectively it can utilize these extrinsic factors to its advantage.

Genetic Control

Genetic control is the ability of plants to manage their developmental processes based on intrinsic genetic information. This genetic command center governs everything from growth rates to reproduction strategies.
Like a well-programmed computer, the plant’s genetic material consists of:

• DNA Sequences: These dictate what hormones are produced and how they are distributed.
• Gene Expression: Controls when and where proteins needed for development are synthesized.

Through genetic control, plants can adapt over generations to respond better to extrinsic factors, such as developing thicker leaves in drought-prone areas. Changes in genetic control enable plants to innovate new survival tactics, enhancing their ability to thrive in diverse environments.

Environmental Factors

Environmental factors encompass all the external resources and conditions that influence a plant’s ability to reach its genetic potential. These include all abiotic factors like climate and soil properties, and biotic elements such as interactions with other organisms.
Environmental factors can drastically alter a plant's life depending on their variability and intensity:

• Competition from Other Plants: Influences access to sunlight and nutrients.
• Animal Activity: Can affect seed dispersal or result in damage.
• Human Impact: Urbanization and agriculture can both restrict and enhance growth opportunities.
• Climate Change: Alters long-established environmental norms, requiring rapid adaptation.

Understanding the complex interplay of environmental factors is crucial for managing ecosystems and supporting sustainable plant development.