What is the root system of wheat and what are its features?
Wheat is a member of the monocot class, the cereal family. Its importance in the life and history of mankind can hardly be overestimated. This is the main raw material for the production of flour and all types of bakery products. The plant is widely used as a technical or fodder crop.
Features of the wheat root system
Roots up to 2 m long feed plants with essential elements, however, they do not absorb water over the entire surface. Moisture is absorbed by thin hairs covered with plant mucus. This area is called the suction zone. Nearby is the division zone - the part that is responsible for growth.
Interesting! Another feature of wheat roots is their density: they occupy up to 300,000 km per 1 hectare of sown soil.
Root type
Wheat, like almost all monocots, has a fibrous system: instead of a pronounced main root there is a cluster of lateral ones. This allows the crop to cover a larger area, but the lateral roots do not go deep into the soil. In essence, the fibrous system is a development in breadth, not in depth.
The tillering node plays an important role in the development of cereal roots. - several underground stem nodes close to each other. Under good conditions, several such knots are tied. They look like a thickening of the stem in the soil, at a depth of 1–3 cm. They are formed in the development phase of 3-4 leaves.
More and more shoots are formed from the node - its death or damage completely destroys the plant.Therefore, preserving this formation is one of the highest priority tasks of agronomists when sowing.
A large number of shoots on one plant reduces efficiency resources absorbed by it, therefore it is generally accepted that for a cereal with 4-5 shoots, the number of additional ears optimally correlates with their quality. Under such conditions, additional shoots do not differ from the main shoot in terms of straw length, size and number of spikelets and grains.
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How does the root grow and develop?
When the pericarp at the bottom of the grain bursts, the main root appears. After 2-3 days, the first 2 lateral roots are formed, after another 1-2 days the second pair develops. Above them, the sixth and seventh ones are formed, which grow at a right angle relative to the first 2 pairs.
Reference! Since these roots originate from the embryonic seed, they are called embryonic. They persist throughout the life of the cereal, although they occupy a relatively small part of the entire system.
At the beginning of development, 4 leaves on the embryonic stem at the level of 1 leaf begin to form Tillering nodes with adventitious roots, which still look like small papillae. As they grow, they break through the leaf from which they were founded, as they are close to each other.
What factors influence
Many factors influence the development and growth of roots: fertilizers, soil temperature and humidity, soil structure and acidity, sowing time.
For proper formation of the primary root system, soil temperature should be within +15…+20°С. Development will begin at lower rates, but then it will be slower.The tillering node is affected by soil moisture: if the soil is dry, it will not receive enough nutrients.
The plant does not develop well in soil that is too acidic. Acidity negatively affects the absorption zone, preventing the absorption of minerals.
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The role of fertilizers in root development
The soil rarely contains enough nutrients in an easily absorbed form. Therefore, wheat is additionally fertilized. An incorrect ratio of phosphorus, potassium and nitrogen reduces plant productivity and grain quality, and increases vulnerability to disease.
The amount of minerals to form a sufficient grain yield per 1 ha:
- 25–35 kg nitrogen;
- 11–13 kg phosphorus;
- 20–27 kg potassium;
- 5 kg calcium;
- 4 kg magnesium;
- 3.5 kg sulfur;
- 5 g boron;
- 8.5 g copper;
- 270 g iron;
- 82 g manganese;
- 60 g zinc;
- 0.7 g molybdenum.
Nitrogen fertilizers are applied in early spring. They accelerate tillering, increase the density of the stem and the number of segments of the spike shaft. When the plant begins to grow into a tube, a second feeding is carried out, which increases the yield. The third time the wheat is fertilized when it heads.
Secondary roots in winter wheat
Winter crops have primary roots, which are formed in the embryonic hypocotyl (embryo stalk) of seeds, and secondary ones, developing from tillering nodes. The latter appear 20 days after germination. During the tillering period, 2 roots are formed from each new stem, which feed the side shoots. At the same time, the primary roots do not stop their work, and if the secondary ones have not developed (for example, due to drought), then they completely provide the grain with minerals and water.
Attention! Secondary roots form only with a sufficient level of humidity (60–70% of the total moisture capacity) and temperatures within +10…+24°C. They grow more intensively if the wheat was sown to a depth of 3-4 cm.
The absorption activity of the secondary system is influenced by an element such as sulfur. The microelement is involved in carbohydrate and nitrogen metabolism, ensures the accumulation of starch and sugar in grains. If there is a lack of substance in the soil and roots, the crop yield decreases.
Sulfur content in winter wheat roots: 5:1 ratio with nitrogen.
Conclusion
The root system of wheat is just as important to obtaining a rich harvest as the stem. It transports water and nutrients, influencing the process of photosynthesis. Roots develop correctly at optimal humidity, temperature, and soil composition.