How to prevent chilling injury of solanaceous vegetables.

The chilling injury of solanaceous vegetables often occurs in greenhouse vegetable planting in spring. Although the damage is not as serious as freezing injury, it also has a certain impact on crop yield and quality, which needs the attention of vegetable farmers. Next, I will talk about the symptoms and effects of chilling injury of solanaceous vegetables, and the remedial and preventive measures after chilling injury.

First, what is chilling injury?

Chilling injury refers to the low temperature injury above 0℃ during the growth and development of crops, which delays the growth of crops or hinders the physiological activities of reproductive organs, resulting in poor differentiation of purple leaves, white leaves and flower buds and slow discoloration of fruits, resulting in reduced production.

The occurrence of chilling injury depends on the interaction of three factors: the sensitivity of eggplant vegetables to low temperature, the degree of low temperature in the environment and the duration of low temperature

Frostbite can be divided into two types: direct injury and indirect injury. First, plants show obvious symptoms after being attacked by low temperature, which is called direct injury; Second, plants do not show obvious symptoms, but their physiological activities are obviously affected, which is called indirect injury.

Second, the symptoms and effects of chilling injury of solanaceous vegetables

1, abnormal blade

(1) The leaves are purple.

This is caused by the lack of phosphorus in plants. The absorption and transportation of phosphorus by plants are greatly influenced by ground temperature. When the ground temperature is lower than 12℃, the absorption and transportation of phosphorus by plants are greatly affected, and the most suitable ground temperature for phosphorus absorption and utilization is 2 1 ~ 28℃.

② Leaves grow slowly or even die.

Eggplant vegetables will have symptoms such as leaf separation, slow growth, non-stretching leaves or slow growth after encountering low temperature. Some will show drooping leaves and wrinkles on the edges of leaves. Long-term chilling injury can easily lead to slow growth and yellowing of leaves, or chlorosis, yellowing or swelling of mesophyll between main veins. When the humidity in the greenhouse is high and the ventilation is low, water stains may appear on the back of the leaves. When plants grow well, water stains can disappear after the sun rises, and when plants are weak, it is easy to cause cell death and leaf death.

2. flower bud differentiation is blocked

The size and quality of vegetable fruits are closely related to flower bud differentiation, and one of the most important factors affecting flower bud differentiation is temperature, such as tomatoes and eggplant in eggplant vegetables. The temperature required for flower bud differentiation is 24~25℃ during the day and 15~20℃ at night. If the temperature is too low, which is lower than 17℃ for a long time in the daytime and 10℃ at night, the flower bud differentiation of vegetables will be seriously affected, and the abnormal fruit rates such as falling flowers and fruits, hard fruits, cracked fruits and empty fruits will be greatly increased.

3. Effects on fruits

Cold injury leads to the weakening of plant root absorption function. When plants are photosynthetic during the day, if there is not enough nutrient supply, the products of photosynthesis will be greatly reduced; When the temperature is low at night, the transportation of various organic compounds synthesized during the day to various organs will be hindered, and the fruit will not get sufficient nutrition, and the fruit will slowly expand. At the same time, the fruit needs a certain accumulated temperature during the discoloration period, and the discoloration will naturally slow down if the accumulated temperature is insufficient.

4. Effect on root system

Freezing injury will reduce the ground temperature, hinder the growth of roots, weaken the absorption capacity of roots, and lead to slow growth and poor development of plants; At the same time, a small amount of nutrients absorbed by roots are taken away by the competition of aboveground parts. Without adequate nutrient supply, the roots will slowly die, eventually leading to plant death. This situation is even more harmful because it is slow and has no obvious symptoms.

Third, remedial measures for chilling injury of solanaceous vegetables

1, temperature and humidity control

After the cold injury, the temperature in the greenhouse should be raised slowly, not too fast or too fast, and the air outlet should be opened slowly from small to large to prevent the leaves from losing water too quickly and wilting.

2. Fertilizer and water management

Fertilization and watering management can be carried out in 3-4 sunny days after cold injury, and root-promoting products such as chitin, amino acids, alginic acid and humic acid can be used in combination with high nitrogen water-soluble fertilizer to promote root regeneration. Foliar spraying 1000 times of chitin solution, 500 times of humic acid-containing water-soluble fertilizer solution and 100 times of white sugar solution can promote the recovery of plants as soon as possible.

In addition, after a long period of cold damage and the weather clears up, management should pay attention to proper shading until the plants are fully adapted to the light.

Fourth, preventive measures for chilling injury of solanaceous vegetables

1, keep temperature and raise temperature.

Pay attention to the weather forecast in time, and cover with a film before the weather cools down; Cover the shed film on both sides of the shed and the shed door with grass curtains or non-woven fabrics, and some are insulated and shielded with black films; Regular cleaning and dust removal can reduce the condensation of shed film and improve the light transmittance of the film; Light the heating block in the shed. When the cold current is strong, light it twice continuously at 0~4 o'clock, which can ensure the safety of vegetables from freezing.

Step 2 reduce humidity

There are two ways to reduce humidity. First, covering planting rows with plastic film, spreading grass in operation rows, reasonably pruning and picking leaves, and drip irrigation under film can greatly reduce water evaporation. Second, under the condition of ensuring little influence on the temperature in the shed, the administration should be ventilated more and ventilated less to increase air exchange.

3. Maintenance of blades

First, strengthen the prevention and control of leaf diseases to ensure that leaves are strong; Second, spraying foliar fertilizers such as amino acids, humic acid, chelated calcium and seaweed before the cold current comes to improve the stress resistance of plants; Thirdly, if freezing injury happens carelessly, spraying 1.8% compound sodium nitrophenolate solution in time can also reduce freezing injury.

The above are remedial measures and preventive methods for chilling injury of eggplant vegetables. We can see that the remedy is a last resort, and some early field operations are the key to reduce and prevent the occurrence of chilling injury.