Gibberellic acid, a kaurene-type compound, is a broad-spectrum and highly effective plant growth regulator. It is ubiquitously present in plants as one of the essential endogenous hormones that promote plant growth and development. Gibberellic acid primarily enters plants through leaves, young shoots, flowers, seeds, or fruits, and is subsequently translocated to actively growing tissues to exert its effects. It demonstrates multiple physiological functions: promoting cell and stem elongation, leaf expansion, parthenocarpy, fruit growth, breaking seed dormancy, altering the ratio of male to female flowers, influencing flowering time, and reducing flower and fruit abscission.
1. Rice
– Soak seeds in 10–50 mg/L GA solution for 24 hours before sowing (solution-to-seed ratio: 1:0.8). Stir several times during soaking. This enhances germination rate and germination potential, resulting in uniform sprouting.
2. Wheat
– Soak seeds in 10–50 mg/L GA solution for 6–12 hours (solution-to-seed ratio: 1:0.8). Dry in shade before sowing to improve germination rate, germination potential, and uniformity.
3. Corn
– Soak seeds in 10–20 mg/L GA solution for 2 hours. Dry in shade before sowing to promote earlier and more uniform seedling emergence, increase seedling dry weight, and improve germination rate.
4. Sorghum
– Soak seeds in 5–10 mg/L GA solution for 12–24 hours to stimulate germination, enhance hypocotyl elongation, increase dry weight, and significantly accelerate seedling emergence.
5. Potato
– **Cut tubers**: Soak in 0.5–2 mg/L GA solution for 10–15 minutes.
– **Whole tubers**: Soak in 5–15 mg/L GA solution for 30 minutes.
Both methods break dormancy, accelerate sprouting, stimulate lateral bud growth, speed up shoot development, extend tuber expansion period, and increase yield by 15%–30%. (*Note: Use lower concentrations for short-dormancy varieties and higher concentrations for long-dormancy varieties.*)
6. Sweet Potato
– Soak tubers in 10–15 mg/L GA solution for 10 minutes. Dry and use for warm-bed seedling cultivation to break dormancy and accelerate sprouting.
7. Soybean
– Soak seeds in 3.5 mg/L GA solution for 2 hours to accelerate initial germination speed under 10–15°C conditions, enhance root growth, and increase fresh and dry root weights.
8. Rapeseed
– **Pre-transplanting**: Apply 20 mg/L GA solution to roots to promote early growth and increase yield.
– **Full bloom stage**: Foliar spray 20–25 mg/L GA solution to improve seed setting rate.
9. Cotton
– Soak seeds in 20 mg/L GA solution for 6–8 hours to mitigate delayed germination or seed rot caused by low temperatures and promote germination.
10. Camellia
– Soak seeds in 20 mg/L GA solution for 4 hours to accelerate germination.
11. Eggplant
– **Shallow dormancy**: Soak seeds in 50–100 mg/L GA solution at room temperature for 8 hours to break dormancy and improve germination.
– **Moderate dormancy (e.g., “Liaoqie No.1,” “Liaoqie No.5,” “Xi’an Green Eggplant”)**: Treat seeds with 500 mg/L GA solution for 24 hours for effective dormancy breaking.
12. Lettuce
– Soak seeds in 200 mg/L GA solution for 24 hours to break dormancy and promote early germination.
13. Lycium (Goji Berry)
– Soak seeds in 300 mg/L GA solution for 24 hours, followed by rinsing and sterilization, to improve germination rate and enhance seedling height, leaf number, leaf length, and soluble protein content.
14. Strawberry
– **Semi-forcing cultivation**: Spray 8–10 mg/L GA solution during early growth to advance first inflorescence flowering.
– **Greenhouse forcing cultivation**: Spray 5–10 mg/L GA solution twice after covering the greenhouse (3 days post-insulation, when 30% of buds appear): first at the unexpanded two-leaf stage, second during budding. Focus on spraying heart leaves to accelerate flowering and maturation. (*Note: Adjust concentration based on dormancy depth; avoid spraying non-dormant varieties.*)
15. Chinese Olive (Canarium album)
– Treat seeds with 50–200 mg/L GA solution for 4 hours to break shallow dormancy, shorten germination time, improve germination rate and uniformity, without adverse effects on seedling growth.
16. Panax notoginseng
– Irrigate with 10–20 mg/L GA solution on the day of transplanting to shorten bud dormancy and improve emergence rate, though seedlings may exhibit excessive elongation.
17. Cyclamen
– Soak seeds in 100 mg/L GA solution for 24 hours to advance and synchronize germination.
18. Rhododendron
– Soak seeds in 100 mg/L GA solution for 24 hours to break dormancy in light-sensitive varieties.
19. Mulberry
– Apply 1–50 mg/L GA solution during winter dormancy to advance bud sprouting and flowering by 2–6 days, increase germination rate, and promote winter bud activation.
20. Qinghai Spruce
– Soak seeds in 500 mg/L GA solution for 24 hours to break dormancy and enhance germinati
