Which stage occurs when the first true leaf emerges in onion seedlings?

The stage at which the first true leaf emerges in onion seedlings is known as the Flag Stage. During this developmental stage, the seedling transitions from primarily using energy reserves stored in the seed to beginning photosynthesis as the true leaf develops. The emergence of the first true leaf marks a critical point in the growth of onion plants, indicating that they are ready to start producing their own food through sunlight. This stage is essential for ensuring the plant can gain the nutrients and energy it needs for further growth and development. Understanding these stages is crucial for effective cultivation and management of onion crops, as it helps in determining the appropriate timing for irrigation, fertilization, and pest control.