Detailed Explanation of Pre-Sowing Pretreatment Methods for Bitter Gourd Seeds
① Site selection and land preparation. Bitter gourd is best sown in spring, so site selection and land preparation should be done early. Bitter gourd likes moisture, prefers warmth, tolerates fertilizer but not waterlogging, so plots with deep topsoil, high fertility and convenient drainage and irrigation should be chosen for planting. Before land preparation, apply 5000 kg of high-quality farmyard manure, 40 kg of nitrogen fertilizer, 50 kg of phosphorus fertilizer and 30 kg of potassium fertilizer per mu. Plow to a depth of 30 cm...
1 Seed soakingSoaking seeds in clean water. Different soaking times have a certain effect on the germination of bitter gourd seeds. Generally, as the soaking time is extended, the seed germination capacity (germination vigor and germination rate) gradually increases, reaching a maximum at 12 hours; beyond 12 hours, the germination capacity shows a downward trend. It can be seen that the most suitable soaking time for bitter gourd seeds is 12 hours at room temperature.
Soaking seeds in warm water. Before sowing, soak the seeds in warm water at about 55°C, then let it cool naturally and continue soaking for 12 hours, which helps the seeds absorb water and swell easily. This is because soaking in warm water at 55°C for 15 seconds can basically kill the pathogenic bacteria attached to the surface of bitter gourd seeds and can improve the permeability of the seed coat. This method is simple to use and suitable for treating large quantities of seeds in production.
Soaking seeds in gibberellin. Soaking seeds in gibberellin can significantly increase the germination vigor and germination rate of bitter gourd seeds, with treatment at a concentration of 40 mg/kg giving better results. Gibberellin is a germination-stimulating substance that can promote the synthesis of auxin, increase the activity of enzymes in the seed embryo (such as amylase) and metabolic activity, and promote cell division and expansion. However, gibberellin at low levels has the effect of inhibiting male flowers, so when treating cucurbit seeds, care should be taken to properly control the concentration used.
Soaking seeds in brassinosteroid (BR). BR is a new type of plant growth regulator, and BR can promote cell elongation and division. Experiments show that seed soaking treatment with BR-120 at a dilution of 1:1500 resulted in germination vigor and germination rate significantly higher than the control, with a significant promoting effect on bitter gourd seed germination. Other experiments show that soaking bitter gourd seeds in BR at the two concentrations of 1:4000 and 1:6000 had a certain inhibitory effect on germination.
Soaking seeds in hydrogen peroxide. Treating bitter gourd seeds with hydrogen peroxide can improve the permeability of the seed coat and increase the uniformity of seed germination. Experiments show that soaking seeds in 50% hydrogen peroxide for 3 hours and then rinsing them clean with water has a clear promoting effect on seed germination; its germination vigor and germination rate were increased by 24.04% and 28.1% compared with the control, and the maximum germination rate reached 97%. Hydrogen peroxide is of greater practical significance for seeds used in large-scale production.
2 High-temperature germination acceleration
Different temperatures have a clear effect on the germination of bitter gourd seeds. Within the temperature range of 25°C-35°C, as the temperature rises, both germination vigor and germination rate clearly increase, with germination vigor and germination rate being relatively high within the range of 33°C-35°C. When the temperature exceeds 35°C or is below 33°C, both the germination rate and germination vigor decline very significantly. It can thus be seen that 33°C-35°C is suitable for bitter gourd seed germination, giving not only a high germination rate but also fast germination and relatively uniform germination.
3 Mechanical scarification
The commonly used mechanical scarification method is to pinch the seed coat until it cracks with pliers (or tweezers), then peel it open to expose the radicle. After shell cracking treatment, the germination vigor and germination rate of bitter gourd seeds were very significantly higher than those of the treatment without shell cracking. Shell cracking treatment combined with germination acceleration at 33°C-35°C gave the highest germination vigor and germination rate, very significantly higher than the germination vigor and germination rate under other temperature conditions for germination acceleration. Therefore, shell cracking can clearly improve the germination vigor and germination rate of bitter gourd seeds, and the most suitable temperature for germination after shell cracking is 33°C-35°C.