The diversity of living organisms and their featuresstructure and life activity is studied by biology. Conditions for seed germination are considered by its branch, called botany, which includes a section - the physiology of plants. The main conditions necessary for the germination of seeds are the optimum temperature, humidity, free air access, a sufficient number of nutrients for the development of the embryo, and also the mode of illumination. They will be considered below.
What conditions are necessary for germination of seeds
The seed is formed from the seed rudiment andangiosperms is formed as a result of double fertilization discovered by S. Navashin in 1861. Its germination occurs at the moment of getting into optimal environmental conditions, called abiotic factors. The embryo, which is contained in the seed and consists of a root and stem with embryonic leaves, begins to grow, with the seminal peel bursting and the seed seedling appears first. It strengthens in the soil and begins to suck in water and the solutions of mineral salts necessary for the further development of the embryo.
In addition to these substances, for the germination of the seed and itsGrowth requires organic substances such as starch, proteins and fats. Their fetus is obtained either from cotyledons (in dicots, for example, peas, cucumbers, tomatoes, cabbage), or directly from the endosperm found in semen in monocotyledonous plants (wheat, rice, rye). Thus, favorable abiotic factors and the presence of nutrients are conditions necessary for the germination of seeds.
Physiological mechanisms of seed germination
If you have such an assignment:characterize the role of the conditions necessary for germination of seeds, we advise 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 is called the transition of the seed from the state of rest to the vegetative growth of the embryo, which ends with the formation of a seedling from it.
Seeds of some plants can sprout immediatelyor shortly after ripening. In many tree species, for example, in gymnosperms - spruce, pine, cedar, and in most forest grassy plants, the seeds have a long period of rest and germinate only after 1-2 years or more. This time interval is very important. Thus, in plants of temperate latitudes, germination is stimulated by low winter temperatures. Such an environmental factor, as illumination, does not always influence the germination conditions of seeds, since most of them develop in the dark.
Optimum temperature value
The most important conditions for seed germination arefavorable abiotic factors, among which 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, others (pumpkin, tomatoes, cucumbers) require that the soil warms up to a temperature of +10 - +12 degrees.
In vegetable growing, this method is often usedincrease the germination of seeds, as their heating. To do this, you can use electrical appliances, and seeds of plants of the family of pumpkin: cucumbers, zucchini, watermelons, legumes (beans, peas, soybeans) are soaked in water at a temperature of 35-45 ° C, and then, after cooling, dried. Warming the seeds one to two weeks before sowing into the soil increases the energy of their germination, preventing the delay of vegetation, increases the yield.
The role of moisture in germination of seeds
Continuing to study the conditions necessary forgermination of seeds, we shall stop on value of water. Its presence in the soil provides the processes of swelling of the seed coat, activating the hydrolysis of starch. The very process of germination begins with the moment of seed absorption of a large volume of water, which flows directly to the embryo. His cells actively absorb the glucose solution and begin to quickly divide, which contributes to the growth of the embryonic root. For example, beet seeds absorb water 1.2 times their mass, and clover - 1.5 times. In household plots, a method of soaking seeds in water is widely used to achieve the germination of the germinal root.
The effect of oxygen on the development of seed
Considering the main conditions for the germination of seeds,we note the need for free air access, 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 influence of oxygen or air supplied from the compressor. The seeds that have a low germination energy (carrots, parsnips, onions) are most often bubbled.
What is EM technology?
If we turn to modern agrarians with a requestto 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, for example, yeast. In the solution of this preparation, soaked seeds prepared for planting for 2-3 hours. This technology stimulates growth processes and enhances the energy of germination of seeds, and also increases the immunity of plants to agricultural pests and increases yield.
Scarification of seeds
To consider all the conditions of seed germination,it is necessary to stop 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 grinding, the seed peel is damaged. Thanks to this method, the water necessary for the germination of the seed gets to the embryo faster.
Availability of a sufficient number of nutrientsubstances - an important condition for the germination of seeds, especially those that are small in size, and therefore a small supply of their own nutritional elements. Seeds of tomatoes, onions, carrots, cabbage are draped, that is, they are covered with a layer of nutritious organic substances that adhere to the seed with a solution of starch-paste or freshly prepared mullein. Before dragee, the seeds are calibrated, that is, sorted, leaving the largest and regular shape. This method, which influences the conditions of germination of seeds, helps to increase their germination and enhances the germination energy.
In this paper, the main conditionsthe germination of the seed, namely moisture, the optimum temperature, depending on the plant species and its variety, the presence of oxygen in the air, and also in the soil, a sufficient supply of nutrients for the development of the embryo, and modern methods that improve the germination conditions of the seeds.