Write short notes on the following Quiescent center Double fertilization Dormancy in seeds Structure and function of root cap?

Quiescent center:
- The quiescent center is a group of cells located at the tip of the root meristem in plants.
- These cells are in a state of dormancy and do not actively divide, but instead serve as a reservoir of stem cells that can give rise to new root tissues when needed.
- The quiescent center plays a crucial role in maintaining the growth and development of the root by regulating the balance between cell division and differentiation.

Double fertilization:
- Double fertilization is a unique process that occurs in flowering plants, where two sperm cells fertilize two different cells within the ovule.
- One sperm cell fertilizes the egg cell to form a zygote, which develops into the embryo, while the other sperm cell fertilizes the central cell to form the endosperm, which provides nutrients to the developing embryo.
- Double fertilization ensures the proper development of the embryo and endosperm in plants, leading to successful seed formation.

Dormancy in seeds:
- Dormancy in seeds is a period of suspended growth and development that allows seeds to survive unfavorable environmental conditions until conditions are more favorable for germination.
- Dormancy can be caused by factors such as temperature, light, moisture, and chemical inhibitors present in the seed coat.
- Once the conditions are right, dormancy is broken, and the seed can germinate and grow into a new plant.

Structure and function of root cap:
- The root cap is a protective structure located at the tip of plant roots.
- It is made up of a layer of cells that secrete a mucilage substance to lubricate the root as it grows through the soil.
- The root cap also helps to sense gravity and other environmental cues, guiding the root in its growth direction.
- Additionally, the root cap protects the delicate root meristem behind it from damage as the root pushes through the soil.

Quiescent Center

- A group of undifferentiated cells located at the root apex.
- Maintains the pluripotency of surrounding stem cells.
- Regulates root growth and development by releasing signaling molecules.

Double Fertilization

- A unique process in angiosperms where two sperm cells fertilize the egg and a central cell (polar nucleus).
- Results in the formation of a diploid zygote and a triploid endosperm.
- Essential for seed and fruit development.

Dormancy in Seeds

- A state of metabolic inactivity that prevents seed germination under unfavourable conditions.
- Maintained by physiological and molecular mechanisms, such as the presence of inhibitory substances or impermeable seed coats.
- Broken by specific environmental cues, such as moisture, light, or temperature.

Structure and Function of Root Cap

- A specialized structure located at the tip of the root.
- Consists of parenchyma cells filled with amyloplasts (starch-filled plastids).
- Protects the delicate meristematic cells at the root tip.
- Assists in root penetration into the soil by secreting mucilage and enzymes, lubricating the root's passage.
- Senses gravity and directs root growth accordingly.