Embryo

Definition

An embryo is an early developmental stage of a multicellular organism, particularly in the context of seed plants and animals, where it develops from the fertilized egg. This stage is crucial as it involves significant cellular division and differentiation, leading to the formation of various tissues and organs. In seed plants, the embryo is contained within the seed and plays a key role in the plant's reproductive cycle.

5 Must Know Facts For Your Next Test

1. The embryo is formed after fertilization when the zygote undergoes rapid cell divisions called cleavage.
2. In flowering plants, the embryo typically consists of a small shoot (plumule), root (radicle), and one or more cotyledons that provide nutrients during early development.
3. The protective seed coat surrounds the embryo and helps prevent desiccation and damage until germination occurs.
4. The successful development of the embryo depends on environmental factors such as water, temperature, and light conditions.
5. Embryos can undergo dormancy, a state in which they remain inactive until conditions are favorable for growth, enhancing survival rates in seed plants.

Review Questions

• How does the structure of the embryo differ between monocots and dicots, and what implications does this have for their development?
  • Monocot embryos typically have one cotyledon, while dicot embryos have two cotyledons. This structural difference affects nutrient storage and distribution during early growth. In monocots, the single cotyledon often functions in nutrient absorption from the endosperm, while dicots rely on their two cotyledons for greater nutrient reserves. This variation impacts how each type of plant establishes itself during germination and can influence overall growth patterns.
• Evaluate the importance of the endosperm in supporting embryonic development in seed plants.
  • The endosperm is crucial for embryonic development as it provides essential nutrients that support the growing embryo. It serves as a food reserve that sustains the embryo during its early stages before it can photosynthesize or establish a root system to access soil nutrients. The quality and quantity of endosperm can directly affect seed viability and plant health after germination, making it a vital component of seed development.
• Analyze how environmental factors influence embryonic development and survival in seed plants.
  • Environmental factors such as water availability, temperature, and light exposure play significant roles in embryonic development and survival. Adequate moisture is essential for initiating germination, while temperature influences metabolic processes crucial for growth. Additionally, light conditions affect photosynthetic capacity once the plant emerges. If environmental conditions are not favorable, embryos may enter dormancy to enhance survival until suitable conditions return, showcasing an adaptive strategy for resilience in varying habitats.

Related terms

Germination: The process by which a seed develops into a new plant, involving the growth of the embryo once conditions become favorable.

Zygote:

The fertilized egg that forms when a sperm cell unites with an egg cell, eventually developing into an embryo.

Endosperm: A nutrient-rich tissue that supports the developing embryo in seed plants, providing essential resources for growth.