Conditions that lead to seed germination.

1. Adequate moisture: Seeds require a certain level of moisture to germinate. Without enough water, the seed will not be able to absorb the necessary nutrients and begin the germination process.

2. Proper temperature: Different seeds have different temperature requirements for germination. Some seeds require warm temperatures, while others need cooler temperatures. If the temperature is too high or too low, the seed may not germinate.

3. Oxygen: Seeds need oxygen to germinate. Oxygen is necessary for the seed to break down stored food reserves and begin growing.

4. Light: Some seeds require light to germinate, while others need darkness. Light can trigger the germination process in certain seeds by breaking down inhibitors that prevent germination.

5. Soil quality: The quality of the soil can also affect seed germination. Seeds need a suitable growing medium with the right balance of nutrients and pH levels to germinate successfully.

6. Scarification: Some seeds have hard seed coats that need to be scarified or broken down before germination can occur. This can be done naturally through weathering or artificially through mechanical or chemical means.

7. Stratification: Some seeds require a period of cold temperatures to break dormancy and trigger germination. This process is known as stratification and mimics the natural conditions that the seed would experience in the wild.

8. Hormones: Plant hormones such as gibberellins and auxins play a crucial role in seed germination by regulating the growth and development of the seedling.

9. Microorganisms: Some seeds require the presence of specific microorganisms in the soil to germinate. These microorganisms help break down organic matter and release nutrients that the seed can use for growth.

10. Seed maturity: Seeds need to be mature before they can germinate. Immature seeds may not have developed enough to successfully germinate and grow into a healthy plant.

Environmental Conditions:

- Water availability: Adequate moisture is crucial for imbibition and metabolic processes.
- Temperature: Optimal temperature range specific to each species; may require specific stratification (warm/cold periods) to overcome dormancy.
- Light: Light can trigger or inhibit germination in some species (photoblasticity); red and blue light receptors involved.
- Oxygen availability: Aeration is essential for respiration and metabolic activity.

Internal Seed Factors:

- Genetic program: Inherent characteristics of the seed that influence germination timing and response to environmental cues.
- Viability: Seed must be viable (living) and have sufficient energy reserves.
- Dormancy: Mechanisms (e.g., mechanical, chemical) that prevent premature germination until certain conditions are met.
- Embryonic growth potential: The seed must contain a viable embryo capable of resuming growth.

Exogenous Factors:

- Seed pretreatments: Mechanical scarification (e.g., sandpaper), chemical treatments (e.g., acids), or controlled dormancy-breaking techniques.
- Hormonal regulation: Hormones (e.g., gibberellins, cytokinins) can promote or inhibit germination.
- Environmental signaling molecules: Chemical cues (e.g., ethylene, smoke) can trigger germination in response to specific environmental conditions.
- Pathogens: Fungal or bacterial infections can impair germination or inhibit seedling growth.

Other Factors:

- Soil conditions: Proper soil pH, moisture retention, and aeration are important for germination and seedling establishment.
- Seedbed characteristics: Factors such as mulch or cover crops can influence soil temperature, moisture, and light penetration.
- Time of year: Seasonality and day length can affect germination timing and success.