In protected cucumber cultivation, a common issue known as "flower topping" or "melon topping" can occur. This phenomenon is characterized by the cessation of plant growth, with the growing tip becoming tight and unresponsive. The top leaves become densely packed, and within a short time, clusters of male and female flowers form, leading to the formation of a self-sealed top—commonly referred to as "flower topping." If a small fruit appears at the top, it's called "melon topping." Once this condition occurs, new leaves and shoots stop emerging, while the middle and lower parts of the plant turn dark green, shriveled, and swollen. If not addressed promptly, the plants may die quickly, resulting in early harvests that significantly impact economic returns.
The primary cause of "flower topping" and "melon topping" is related to environmental stress, especially low temperatures in the greenhouse, particularly at night. A large temperature fluctuation between day and night can trigger excessive female flower formation. During the early stages of growth, after 3–4 true leaves have developed, more than 20 leaf and flower primordia are already differentiated at the growth point. While some will develop into leaves, others become female or male flowers. Under conditions of large temperature differences and short daylight hours, female flower development is favored, which consumes more nutrients. This imbalance can suppress vegetative growth, leading to the "flower topping" phenomenon.
Other contributing factors include low soil temperature, overly dry or wet soil, the use of uncomposted manure, or an excess of nitrogen fertilizer, all of which can hinder root development and reduce nutrient uptake. Additionally, some farmers use growth regulators like gibberellins or similar compounds to boost yields. These substances can increase endogenous hormones in the plant, directing nutrients toward female flower development and potentially causing multiple female flowers to form, while male flowers degenerate. This results in a plant with only old leaves and no new growth, effectively becoming self-sealed.
To prevent and manage "flower topping," it is essential to maintain proper growing conditions. Seedlings should be raised in a warm environment, ensuring that nighttime temperatures during the flower bud differentiation stage do not drop below 13°C, with daytime temperatures above 23°C. Greenhouse coverings should be managed to maximize sunlight exposure, and supplemental lighting can be used if needed. After planting, regular soil loosening helps improve soil temperature and aeration, promoting healthy root development. Adequate watering is also crucial—ensuring sufficient water during planting and seedling stages, while adjusting based on weather, plant growth, and location within the greenhouse.
Fertilization should be well-decomposed and evenly applied to avoid root damage. For plants already showing signs of "flower topping," it's important to harvest ripe fruits promptly and thin out excess female flowers or melons. Stronger plants can retain 1–2 fruits, while weaker ones should have all fruits removed to redirect nutrients back to vegetative growth. Spraying cytokinin at a concentration of 300–400 times every seven days can stimulate lateral bud growth and help restore normal plant development.
Therefore, amino acids are not only essential for human health, but also play an important role in beauty and skin care products.
Amino acids are the basic units of proteins and are essential organic compounds in life. There are about 500 different amino acids in nature, but among the amino acids that make up the proteins of living organisms, 20 are standard amino acids, which are connected in different sequences to form proteinaceous proteins that perform various physiological functions in living organisms.
Amino acids can be divided into the following categories according to their location and function in proteins
1.Essential amino acids
9 amino acids that the body cannot synthesize by itself or the synthesis speed cannot meet the needs, and must be ingest through food, including lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine and histidine (infants also need histidine).2.Non-essential amino acids
The human body can synthesize by itself and does not need to obtain directly from food, including glutamic acid, aspartate, alanine, serine, glycine, proline, cysteine, etc.3.Conditional essential amino acids
Under specific conditions (such as disease, stress), the human body's synthetic ability is reduced, and additional supplements are needed, such as arginine, glutamine, etc.Amino acids are also widely used in the field of skin care, as skin care ingredients, they mainly have the following effects
1.Moisturizing
Some amino acids such as glycine, alanine, etc. have good hygroscopic properties, which can help the skin retain moisture and enhance its moisturizing ability.2.Repair
Such as arginine, glutamic acid, etc. participate in the repair and regeneration process of skin cells, promoting wound healing.3.Anti-aging
Certain amino acids have antioxidant effects that can help fight free radical damage and slow down skin aging.4.Cleansing
Amino acid surfactants, such as sodium lauryl sarcosine, are commonly used in cleansing products for sensitive skin due to their mild, non-irritating properties.Therefore, amino acids are not only essential for human health, but also play an important role in beauty and skin care products.
Amino Acids,Taurine,L-Tyrosine, Food additives
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