Problem 8 - Biology Today and Tomorrow with Physiology

Question

The ______ are parts of a mature seed. a. stamen and carpel b. embryo, food reserves, and seed coat c. stigma, style, and ovary d. male and female gametophytes

Step-by-Step Solution

Answer

The correct answer is (b) embryo, food reserves, and seed coat.

Step 1: Understand Seed Components

To find the correct answer, we need to identify the typical parts of a mature seed. A seed typically consists of an embryo, food reserves, and a seed coat, which are crucial for the seed to develop into a new plant under the right conditions.

Step 2: Analyze the Options

Let's analyze each of the options given: - (a) Stamen and Carpel: These are parts of a flower, not a seed. - (b) Embryo, Food Reserves, and Seed Coat: These are indeed components of a mature seed. - (c) Stigma, Style, and Ovary: These are parts of a flower's pistil, not a seed. - (d) Male and Female Gametophytes: These are part of the sexual reproduction process in plants, not specifically seed parts.

Step 3: Select the Correct Answer

Based on the analysis, option (b) Embryo, Food Reserves, and Seed Coat is the correct answer, as these are indeed the parts that make up a mature seed.

Key Concepts

Embryo

The embryo is a crucial component of a seed. It represents the young plant in its earliest stage of development. When looking inside a seed, the embryo can be seen as a small, undeveloped plant. It consists of embryonic leaves, stem, and root.
The embryo plays a vital role once conditions are favorable for germination. It uses nutrients stored within the seed to grow and start the process of developing into a mature plant. What makes up an embryo?

• Cotyledons: These are the embryonic leaves. Depending on the plant species, a seed may have one or two cotyledons.
• Hypocotyl: This forms the transition between the cotyledons and the root.
• Radicle: The embryonic root, which is the first to emerge during germination.

The health and development of the embryo are vital for the successful sprouting and growth of a new plant. Understanding the embryo is fundamental in seed anatomy as it is the powerhouse for future plant growth.

Seed Coat

The seed coat is the outer coverage of the seed. Think of it as the protective layer that keeps the seed safe. It serves as the first line of defense against harsh environmental conditions. This includes protection from pests, diseases, and mechanical damage.
The seed coat's structure can vary depending on the plant species, but it often includes a tough, sometimes waterproof layer that prevents damage to the seed. Functions of the seed coat:

• Protection: Shields the embryo and food reserves from physical harm and infection.
• Regulation: Controls the seed's interaction with its environment by regulating water intake and, in some cases, detecting environmental signals for germination.
• Dispersal Aid: Some seed coats have adaptations that help in seed dispersal. This can include hooks, sails, or fleshy coatings that encourage animals to transport the seeds.

Without this protective coat, a seed would be vulnerable and unlikely to survive the conditions outside until it is ready to germinate.

Food Reserves

Food reserves are a crucial part of the seed's anatomy as they supply the energy necessary for the embryo to grow, especially during the early stages before the seedling can perform photosynthesis. They are stored in various forms, depending on the type of plant. Types of food reserves:

• Carbohydrates: Often stored as starch, providing a quick energy source during germination.
• Proteins: Essential for building the structures needed for the growing plant.
• Fats: Another energy source, especially in seeds like nuts and some grains.

These reserves ensure that the young plant has all the necessary nutrients to reach the surface and begin photosynthesis, leading to the establishment of a self-sustaining plant.
Understanding food reserves helps clarify why seeds are such a vital resource for growth and survival in plants.