what is a seed coat ?
what is it’s function ?
The correct answer and explanation is:
A seed coat is the outer protective layer that surrounds a seed. It develops from the outer layers of the ovule after fertilization and acts as a barrier between the seed’s internal parts and the external environment. The seed coat is usually tough and hard, varying in thickness depending on the type of seed and the plant species.
The main function of the seed coat is to protect the seed from physical damage, pathogens, and drying out. Since the seed contains the embryonic plant and the stored nutrients needed for germination and early growth, safeguarding these vital components is crucial for the seed’s survival and successful development into a new plant. The seed coat prevents injury from mechanical forces such as pressure or abrasion, which might occur during dispersal or while the seed lies dormant in the soil.
Additionally, the seed coat helps regulate water uptake. It acts as a barrier to water until conditions are suitable for germination. When environmental factors like moisture, temperature, and light are favorable, the seed coat allows water to enter the seed, triggering metabolic processes that initiate germination. Some seed coats are impermeable to water for long periods, which helps seeds remain dormant until conditions improve, ensuring better chances for seedling survival.
The seed coat also provides protection against microbial attack by fungi and bacteria. Its tough structure and sometimes chemical composition help prevent infections that could damage the embryo inside.
In summary, the seed coat is essential for protecting the seed from mechanical injury, water loss, and infection, while also controlling when germination can occur. This protective function increases the likelihood that the seed will survive until it can grow into a new plant under favorable environmental conditions.