Chilling injury of cucumber in greenhouse occurs mainly in winter and early spring. Poor room insulation performance is poor, watering is too large during the cold period; or the amount of air is too quick and too large, cold air intrusion causes the temperature of the greenhouse to fall; or the night temperature is too low to cause premature leaf aging and loss of photosynthesis and other factors. As a result, the plants exhibited symptoms such as focal edge, brown spots, curled leaves, dryness, baldness, and flower topping. The simple identification of the symptoms of cold damage in cucumbers in greenhouses and the prevention of chilling injury in advance are important steps in improving the yield and benefits of cucumbers in greenhouses. 2007-9-24 Fresh To Ground Ginger,Fresh Ginger To Dry,Grated Fresh Ginger,Organic Dried Ginger Jining Yuanheng International Trading Co.,Ltd , https://www.china-garlic-exporter.com
Cold Damage Identification
1. Blades are defocused. In the cotyledon stage, the leaf margin was chlorotic, with white margins and coking. After the colonization, the leaf margins of the upper leaves were dark green and dry and yellow. Even the cloudy days are long and the ground temperature is drastically reduced. If the soil moisture is too large, the roots of the plants will grow roots, the new leaves of the plants will appear coke-edge, and decay will occur under high humidity conditions.
2. Water dip spot. The symptoms mainly occur on the back of the leaves. The initial symptoms are tipping of the tip, chlorotic chlorosis of leaves, and the appearance of water-filled water spots on the back of the leaves. The main reason is that due to the long duration of low temperature and high humidity in the greenhouse, if the development continues, the leaves and leaves of the big veins will die and the entire leaf will wilt and die.
3. Small brown spots. More than 14-15 pieces of true leaves spread on the middle and lower leaves. The diseased leaf first appears white or brown streak (also called dotted spot) next to the large vein. The disease is not contiguous with the vein limitation in the early stage. The stripe is close to the big leaf vein, the leaf spot is necrotic in the leaf spot, and the leafy meat is between the large leaf veins. There are scattered brown spots, or oily veins appear in the veins. The relative humidity of the air in the greenhouse is large and the light is insufficient. The temperature is below 10°C for a long time. A temperature of 10 cm below 12°C is beneficial to the occurrence and spread of brown spots.
4. Tiger leaf. The leaf veins of the main veins turn green and yellow, and the leaves are like tiger-like spots. Due to the low ground temperature during plant colonization, affecting the development of the root system, leading to leaf aging, physiological function decline, or the temperature in the middle of the night before the indoor temperature is lower than 15°C, resulting in the carbohydrates produced by photosynthesis can not be turned outwards and deposited on the leaves. The leaves are then yellowed to produce a tiger leaf.
5. Parachute leaf. Fresh leaves near the initial growth point were yellowed, and then the leaf margins began to yellow, with the central part of the leaf blade bulging, and the edges turned backwards, presenting a parachute-like appearance. The main reason is the formation of calcium deficiency in low temperature oligopolistic plants. The greenhouse insulation performance is poor, the temperature continues to drop; when the temperature falls below the limit temperature, calcium absorption is hindered.
6. Flowers topping. The internodes near the growing point of the plant were significantly shorter, forming a cluster of male and female flowers. No new leaves can be formed on the top of the plants, showing flower heads. One of the main reasons is that flowering is caused by rooting or no new rooting. For example, cold roots cause damage to roots and roots, or damage to the roots during planting management. Second, there is a lack of water in the drought and there is a serious shortage of fertilizer. In the final analysis, flowering is the result of reproductive overgrowth and vegetative growth is inhibited.
7. Physiological wither. Occurs in the greenhouse in winter and spring. After the plants are planted, the leaves gradually dry up from the bottom to the bottom, leaving only the top 1-2 green leaves. It is a physiological disease that occurs after cold injury. Pulling up the affected plant found that the root volume was extremely small and damaged. Watering after planting in case of cloudiness is the main reason for the occurrence of symptoms.
8. Bald tip. The upper stems of the plants are fine, the leaves are small, the petioles are long, and the tendrils are weak. The buds of the growing point cannot differentiate and form a bald tip. Cucumber baldness is not only related to species, but also related to environmental conditions. Hybrids are more prone to occur than conventional ones, and the more severe the result is, the more serious the species is. The impact of environmental conditions is mainly low temperature. In particular, after a long period of low temperature and cloudy days after planting, the activity of the root system was weak, and the assimilation weakened. The plant was prematurely decayed.