Question

Bright colour of petals, is due to the presence of (a) chloroplast (b) anthocyanin (c) chromoplast (d) leucoplast.

Short answer

The bright color of petals is due to the presence of chromoplasts.

Step-by-step solution

Understanding the Question

The exercise asks for the reason behind the bright color of petals in a flower. We need to choose between four different types of plastids, which are specialized components within plant cells.

Eliminating Incorrect Options

Chloroplasts are associated with the green color of leaves due to chlorophyll. Leucoplasts are colorless and often found in roots and tubers. Anthocyanins are pigments but not plastids. So, we can eliminate chloroplasts, anthocyanins, and leucoplasts as they do not fit the description of being the source of bright coloration in petals.

Identifying the Correct Answer

Chromoplasts are plastids that contain pigments known for giving flowers and fruits their bright colors. Therefore, the presence of chromoplasts is the cause of bright colored petals.

Key concepts

Chromoplasts

Chromoplasts are fascinating components of plant cells that are primarily responsible for the vivid red, yellow, and orange hues observed in many fruits, flowers, and autumn leaves. These specialized plastids are tasked with synthesizing and storing pigments known as carotenoids. Unlike their green cousins, the chloroplasts, chromoplasts don't play a direct role in photosynthesis. Instead, they attract pollinators and seed dispersers with their bright colors, effectively contributing to the reproductive process of plants.

Function of Chromoplasts:

• Storage of carotenoid pigments, which are responsible for the bright coloring of plant parts.
• Attract pollinators and seed dispersers due to their vivid colors.
• Transformation from chloroplasts during fruit ripening or petal development, marking a shift from photosynthetic activity to attracting agents of pollination and seed dispersal.

Pigments in Plants

Pigments are the compounds within plants that absorb and reflect certain wavelengths of light, resulting in the colors we perceive in their leaves, stems, flowers, and fruits. Chlorophyll, carotenoids, and anthocyanins are among the most well-known pigments in plants. Each has a unique role:

Types of Pigments:

• Chlorophyll: Primarily responsible for the green color of leaves and stems, chlorophyll is involved in photosynthesis, absorbing light to convert carbon dioxide and water into sugars.
• Carotenoids: These are found in chromoplasts and provide yellow, orange, and red colors. They also play a protective role, safeguarding the plant’s cells by absorbing excess light energy.
• Anthocyanins: They give plants blue, purple, or red hues and can serve in protecting them from UV rays and attracting pollinators.

Pigments, beyond contributing to a plant's coloration, also impact a plant's survival. For instance, they play a crucial role in photosynthesis by capturing light energy, and they can also protect plants from harmful radiation.

Plant Cell Structures

Plant cells are remarkable for their complexity and adaptation to supporting life processes. These living building blocks of plants contain various structures, each specialized for particular functions. The cell wall provides support and structure, distinct from the more flexible cell membranes found in animal cells. Inside, the cell is teeming with activity, facilitated by organelles such as the nucleus, endoplasmic reticulum, and golgi apparatus.

Key Organelles in Plant Cells:

• Nucleus: Contains the plant cell’s genetic material and regulates growth and reproduction.
• Chloroplasts: Sites of photosynthesis, their green pigment chlorophyll is essential for this energy-converting process.
• Mitochondria: Known as the powerhouse of the cell, they generate the cell's energy currency, ATP, through respiration.
• Vacuoles: They store nutrients, waste products, and contribute to cell turgor, which is vital for maintaining the shape of the cell.

Understanding these structures is key to comprehending how plants grow, reproduce, and interact with their environment. For example, the presence of large central vacuoles in plant cells is one of the characteristics that allows them to maintain structure and manage water resources in a way that's unique from animal cells.