The variety of living organisms and features of their structure and life is studied by biology. The conditions for seed germination are considered by its branch, called botany, which includes a section - plant physiology. The main conditions necessary for seed germination are the optimal temperature, humidity, free air access, sufficient nutrients for the development of the embryo, as well as the lighting regime. They will be discussed below.
What conditions are necessary for seed germination
The seed is formed from the seed germ and in angiosperms it is formed as a result of double fertilization, discovered by S. Navashin in 1861. Its germination occurs at the moment it enters the optimal environmental conditions, 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 bursts and the seed root appears first. It becomes stronger in the soil and begins to independently absorb water and mineral s alt solutions necessary for the further development of the embryo.
In addition to these substances, organic substances such as starch, proteins and fats are necessary for seed germination and growth. Their embryo receives either from the cotyledons (in dicotyledonous plants, for example, peas, cucumbers, tomatoes, cabbage), or directly from the endosperm located in the seed of 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: characterize the role of the conditions necessary for seed germination, we advise you to start by highlighting the physiological aspects of these processes, scientifically explaining the main conditions necessary for the development of the embryo. So, germination is the transition of a seed from a state of rest further to the vegetative growth of the embryo, ending with the formation of a seedling from it.
Seeds of some plants can germinate immediately or a short time after ripening. In many tree species, for example, gymnosperms - spruce, pine, cedar, and most forest herbaceous plants, the seeds have a long dormant period and germinate only after 1-2 years or more. Thisthe time interval is very important. So, in plants of temperate latitudes, germination is stimulated precisely by low winter temperatures. Such an environmental factor as illumination does not always affect the conditions for seed germination, since most of them develop in the dark.
Optimal temperature value
The most important conditions for seed germination are favorable abiotic factors, among which temperature performs one of the main functions. In agronomy, plants are classified into cold-resistant and heat-loving. This differentiation also applies to seeds. Some, for example, seeds of carrots, lettuce, onions, germinate at low positive temperatures, others (pumpkin, tomatoes, cucumbers) require the soil to warm up to a temperature of +10 - +12 degrees.
In vegetable growing, such a method of increasing the germination of seeds as heating them is often used. To do this, you can use electrical appliances, and the seeds of plants of the pumpkin family: cucumbers, zucchini, watermelons, legumes (beans, peas, soybeans) are soaked in water at a temperature of 35-45 ° C, and then, after cooling, they are dried. Warming up the seeds for one to two weeks before sowing in the soil increases the energy of their germination, preventing a delay in vegetation, and increases the yield.
The role of moisture in seed germination
Continuing to study the conditions necessary for seed germination, let us dwell on the importance of water. Its presence in the soil provides the processes of swelling of the seed coat, activation of starch hydrolysis. The germination process itself starts from the momentabsorption by the seeds of a large volume of water, which goes directly to the embryo. Its cells actively absorb the glucose solution and begin to divide rapidly, 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 home gardens, the method of soaking seeds in water is widely used, achieving the germination of the germinal root.
Influence 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 the processes of intensive respiration of moistened seeds. In agriculture, bubbling is often used: mixing seeds in water under the action of oxygen or air supplied from a compressor. The most frequently bubbling seeds have low germination energy (carrots, parsnips, onions).
What is EM technology?
If we turn to a modern agrarian with a request to determine the conditions for seed germination, then in response, in addition to all known abiotic factors, we will hear a proposal to use microbiological preparations, for example, such as "Baikal EM-1", containing lactic acid, photosynthesizing microorganisms and fungi, such as yeast. In a solution of this drug, seeds prepared for planting are soaked for 2-3 hours. This technology stimulates growth processes and enhances the energy of seed germination, as well as increases plant immunity topests and increases yields.
Seed scarification
To consider all the conditions for seed germination, it is necessary to dwell on such a method as scarification (artificial damage to the seed coat by hand). To do this, use a mixture of seeds with coarse sand or metal filings. As a result of rubbing, the seed coat is damaged. Thanks to this technique, the water necessary for seed germination gets to the embryo faster.
Seed coating
The presence of sufficient nutrients is an important condition for the germination of seeds, especially those that are small in size, which means a small supply of their own nutrients. Seeds of tomatoes, onions, carrots, cabbage are coated, that is, they are covered with a layer of nutrient organic substances that adhere to the seed with a starch solution - paste or freshly prepared mullein. Before drageeing, the seeds are calibrated, that is, they are sorted, leaving the largest and most regular shape. This method, which affects the conditions of seed germination, improves their germination and enhances the vigor of germination.
This article covered 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 improving conditionsseed germination.
