The diversity of living organisms and the features of their structure and activity is studied by biology. The conditions for seed germination are considered by its industry, called botany, which includes a section - plant physiology. The main conditions necessary for seed germination are optimal temperature, humidity, free access of air, a sufficient amount of nutrients for the development of the embryo, as well as the light regime. They will be considered below.
What conditions are necessary for seed germination
The seed is formed from the seed germ and in angiosperms is formed as a result of double fertilization, discovered by S. Navashin in 1861. Its germination occurs when it enters the optimal environment, called abiotic factors. The embryo contained in the seed and consisting of a root and a stalk with germinal leaves begins to grow, while the seed skin breaks and the root of the seed appears first. It hardens in the soil and begins to independently absorb water and solutions of mineral salts necessary for the further development of the embryo.
In addition to these substances, organic matter such as starch, proteins and fats are necessary for seed germination and growth. Their embryo is obtained either from cotyledons (in dicotyledonous plants, for example, peas, cucumbers, tomatoes, cabbage), or directly from the endosperm found in the seed from monocotyledonous plants (wheat, rice, rye). Thus, favorable abiotic factors and the availability of nutrients are the conditions necessary for seed germination.
Physiological mechanisms of seed germination
If you are given the following task: describe the role of the conditions necessary for seed germination, we recommend starting with the illumination of the physiological aspects of these processes, scientifically explaining the main conditions necessary for the development of the embryo. So, germination refers to the transition of a seed from a dormant state further to the vegetative growth of the embryo, ending with the formation of a seedling from it.
The seeds of some plants can germinate immediately or shortly after ripening. In many tree species, for example, in gymnosperms - spruce, pine, cedar, and in most forest herbaceous plants, the seeds have a long rest period and germinate only after 1-2 years or more. This time interval is very important. So, in plants of temperate latitudes, germination is stimulated precisely by low winter temperatures. An environmental factor such as illumination does not always have an effect on seed germination conditions, since most of them develop in the dark.
Optimal temperature
The most important conditions for seed germination are favorable abiotic factors, among which the temperature performs one of the main functions. In agronomy, plants are classified as cold-resistant and thermophilic. This differentiation also applies to seeds. Some, for example, seeds of carrots, lettuce, onions, germinate at low plus temperatures, while others (pumpkin, tomatoes, cucumbers) require that the soil warms up to a temperature of +10 - +12 degrees.
In vegetable growing, they often use such a method of increasing the germination of seeds as their heating. For this, you can use electrical appliances, and the seeds of the pumpkin family plants : cucumbers, zucchini, watermelons, legumes (beans, peas, soybeans) are soaked in water at a temperature of 35-45 ° C, and then cooled, dried. Warming up the seeds for one to two weeks before sowing in the soil increases the energy of their germination, preventing the delay of vegetation, increases productivity.
The role of moisture in seed germination
Continuing to study the conditions necessary for seed germination, let us dwell on the significance of water. Its presence in the soil provides the processes of swelling of the seed peel, the activation of starch hydrolysis. The process of germination begins with the moment of absorption by the seeds of a large volume of water, which flows directly to the embryo. Its cells actively absorb glucose solution and begin to rapidly divide, which contributes to the growth of the germinal root. For example, beet seeds absorb water 1.2 times their mass, and clover 1.5 times. In private households, a method of soaking seeds in water is widely used, achieving germination of the germinal root.
The effect of oxygen on seed development
Considering the main conditions for seed germination, we note the need for free access of air, which is used to ensure intensive respiration of moistened seeds. Bubbling is often used in agriculture: mixing seeds in water under the influence of oxygen or air supplied from a compressor. Most often they sparge seeds with low germination energy (carrots, parsnips, onions).
What is EM technology?
If we turn to modern agrarians with a request to determine the conditions for seed germination, then in response to all known abiotic factors, we will hear a proposal to use microbiological preparations, for example, such as Baikal EM-1, containing lactic acid, photosynthetic microorganisms and fungi, for example yeast. In the solution of this preparation, the seeds prepared for planting are soaked for 2-3 hours. This technology stimulates growth processes and enhances the energy of seed germination, and also increases the immunity of plants to agricultural pests and increases productivity.
Seed scarification
To consider all the conditions for seed germination, it is necessary to dwell on a method such as scarification (artificial damage to the seed skin by hand). To do this, use a mixture of seeds with coarse sand or metal filings. Due to grinding, the seed coat is damaged. Thanks to this technique, the water needed for seed germination gets to the embryo faster.
Seed pelleting
The presence of a sufficient amount of nutrients is an important condition for the germination of seeds, especially those that are small in size, and therefore a small supply of their own nutrients. Seeds of tomatoes, onions, carrots, cabbage are dragee, that is, covered with a layer of organic nutrients that adhere to the seed using a starch solution - paste or freshly made mullein. Before pelleting, the seeds are calibrated, that is, sorted, leaving the largest and most regular in shape. This method, affecting the conditions of seed germination, helps to increase their germination and enhances the energy of germination.
This article highlighted the main conditions for seed germination, namely humidity, optimal temperature, depending on the type of plant and its variety, the presence of oxygen in the air, as well as in the soil, an adequate supply of nutrients for the development of the embryo, and modern methods that improve the conditions for seed germination .