Seed germination requires a suitable temperature, a moderate amount of moisture and sufficient air. First, water is required to swell and soften the seed coat when the seed is germinated.
Followed by the air, the seeds need to constantly breathe during the germination process, and energy can be obtained to ensure the normal operation of life activities.
Finally, the decomposition of nutrients in the seed and a range of other physiological activities need to be carried out at a suitable temperature.
Seed Developmental Stage
When the seeds are immersed in water or fall into moist soil, the hydrophilic substances in the seeds begin to attract water molecules, causing the seed volume to increase rapidly.
After the seeds are inflated, the seed coat becomes soft or ruptured, the seed coat begins to increase in gas permeability, and germination begins. The hydration and enzymes begin to activate, and the respiratory and metabolic effects increase dramatically.
The cells divide and enlarge, so that the embryos begin to grow, and the nutrients stored in the seeds are also consumed in large quantities. The embryo then breaks through the seed coat and is exposed. The seed first emerges from the radicle and then grows out of the germ. Finally, roots, stems, and leaves are grown, and seedlings are formed.
The Germination Rate of Seeds
A successful seed germination factor includes the seed itself and its external conditions, sufficient moisture, suitable temperature, adequate oxygen and sufficient sunlight.
Vitality Intact Embryo
For the conditions of healthy seeds themselves, they must have a living embryo intact. In short, after leaving the mother, it will gradually lose vitality and cannot germinate for more than a certain period of time.
Different seeds have different life spans. For example, seeds of wheat and rice are generally active for three years, while seeds of cabbage and broad beans can live for five to six years. Normal seeds will have sufficient nutrient reserves to supply the materials needed for seed germination. In contrast, dried seeds are often unable to sprout successfully due to lack of adequate nutrition.
After the seeds are formed, they cannot germinate even when the conditions are suitable. This is mainly due to the state of dormancy. Generally you need to promote seed germination by releasing dormancy. For dormant seeds, dormancy should be relieved for different reasons to promote seed germination.
Seed Germination External Conditions
Seed germination itself must have a healthy ability to germinate, and in addition to restoring it, it also requires other suitable external environmental conditions. Then the main thing is plenty of water, the right temperature, and enough oxygen.
Dormant seeds must absorb enough water to initiate a series of enzyme activities and begin to germinate. There is a different absorption of water from different seeds. Seeds containing more protein absorb more water, while starch-based seeds such as wheat and rice contain less water.
Generally, seeds require 25% to 50% or more of their own weight to germinate. You need to create good water absorption conditions for the seeds to meet the water requirements for seed sowing.
The germination of various seeds generally has the lowest, most suitable and highest three base point temperatures. When the minimum temperature is exceeded to a certain limit, only a part of the seeds can germinate, and the temperature during this period is called the highest temperature.
Below the minimum temperature, the seed germination gradually slows, and to a certain extent only a small part of the seed barely germinates, the temperature of this period is called the lowest temperature.
When you understand the optimum temperature for seed germination, you can combine the growth and developmental characteristics of the plant to choose the appropriate sowing season.
After the seeds absorbs water, the respiration is enhanced, so the oxygen demand will increase. The seeds of common crops require more than 10% of the oxygen content around them to be able to germinate normally.
Therefore, excessive moisture in the soil, or poor ventilation caused by the reduction of soil voids in the soil panel will reduce the oxygen content of the soil air, thereby affecting seed germination.
Seeds can be divided into seeds that require light and seeds that are suspected of light. Only a few seeds need to germinate well in the presence of light. However, most of the seed germination has little to do with light, and it works well in dark or light conditions.
Seeds that are easier to germinate can be soaked in cold water or warm water before sowing, and can be sown until the seed coat becomes soft. Some seeds, such as lotus and canna, have hard skin and are not easy to absorb water. You can use a sickle to grind or injure the seed coat and then soak it with warm water. You can sow until the seed coat becomes soft.