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Jun 15
Light can break seed dormancy through a process called photodormancy. When seeds are exposed to light, it triggers a series of biochemical reactions that can break down inhibitors and promote the germination process. Light can also stimulate the production of hormones that are necessary for germination to occur. Additionally, some seeds require specific light conditions, such as certain wavelengths or durations of light exposure, to break dormancy and begin germination. Overall, light plays a crucial role in signaling to seeds that it is time to start growing.
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Google Gemini AI
Jun 15
Light can break seed dormancy through the following mechanisms:
Phytochrome Regulation:
- Phytochromes are light-sensitive proteins that regulate gene expression.
- Red light (R) converts phytochrome B (phyB) to its active form (Pfr-phyB), which triggers physiological responses, including the breakdown of light-sensitive germination inhibitors.
- Blue light (B) promotes the degradation of Pfr-phyB, preventing seed germination.
Gibberellic Acid (GA) Signaling:
- Light stimulates the synthesis of GA, a plant hormone that promotes seed germination.
- GA weakens the endosperm or seed coat barriers, allowing the embryo to expand and emerge.
Degradation of Abscisic Acid (ABA):
- ABA is a plant hormone that inhibits seed germination.
- Light induces the expression of ABA-degrading enzymes, which reduce ABA levels and promote seed germination.
Regulation of Seed Coat Permeability:
- Light can increase the permeability of the seed coat, allowing water and oxygen to enter and initiate metabolic processes necessary for germination.
Photodormancy:
- In some seeds, light is required to induce dormancy, known as photodormancy.
- This prevents germination in conditions where light would be insufficient for seedling survival.
Examples of seeds that require light for germination include:
- Lettuce (Lactuca sativa)
- Petunia (Petunia spp.)
- Celery (Apium graveolens)
- Parsley (Petroselinum crispum)
By breaking seed dormancy, light ensures that seeds germinate at the appropriate time and under favorable conditions for seedling establishment.
Phytochrome Regulation:
- Phytochromes are light-sensitive proteins that regulate gene expression.
- Red light (R) converts phytochrome B (phyB) to its active form (Pfr-phyB), which triggers physiological responses, including the breakdown of light-sensitive germination inhibitors.
- Blue light (B) promotes the degradation of Pfr-phyB, preventing seed germination.
Gibberellic Acid (GA) Signaling:
- Light stimulates the synthesis of GA, a plant hormone that promotes seed germination.
- GA weakens the endosperm or seed coat barriers, allowing the embryo to expand and emerge.
Degradation of Abscisic Acid (ABA):
- ABA is a plant hormone that inhibits seed germination.
- Light induces the expression of ABA-degrading enzymes, which reduce ABA levels and promote seed germination.
Regulation of Seed Coat Permeability:
- Light can increase the permeability of the seed coat, allowing water and oxygen to enter and initiate metabolic processes necessary for germination.
Photodormancy:
- In some seeds, light is required to induce dormancy, known as photodormancy.
- This prevents germination in conditions where light would be insufficient for seedling survival.
Examples of seeds that require light for germination include:
- Lettuce (Lactuca sativa)
- Petunia (Petunia spp.)
- Celery (Apium graveolens)
- Parsley (Petroselinum crispum)
By breaking seed dormancy, light ensures that seeds germinate at the appropriate time and under favorable conditions for seedling establishment.
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