As a sulfur-containing dipeptide amino acid, L-Alanyl-L-Cystine functions as a plant growth regulator primarily by participating in plant metabolic regulation, enhancing stress resistance, promoting hormone balance, and improving plant nutritional status. The specific mechanisms of action are as follows:
Ⅰ.Participation in Plant Metabolic Regulation
1. Promotion of Protein Synthesis
Plant growth and development rely on extensive protein synthesis. As a dipeptide, L-Alanyl-L-cystine can directly participate in protein synthesis within plants, providing essential building blocks for cell division, elongation, and differentiation, thereby promoting plant growth and development.
2. Regulation of Enzyme Activity
Enzymes play a critical role in plant physiological processes. L-Alanyl-L-Cystine can interact with enzyme molecules, influencing their activity and stability. For example, it may regulate enzymes involved in photosynthesis and respiration, optimizing metabolic efficiency and providing more energy and nutrients for plant growth.
Ⅱ.Enhancement of Plant Stress Resistance
1. Reactive Oxygen Species (ROS) Scavenging
Under stress conditions, plants produce large amounts of reactive oxygen species (ROS) such as superoxide anions and hydrogen peroxide, which can cause oxidative damage to plant cells. The cystine component of L-Alanyl-L-Cystine contains sulfhydryl (-SH) groups with strong antioxidant properties, enabling it to neutralize ROS, alleviate oxidative stress, and protect plant cells from damage.
2. Regulation of Osmotic Balance
L-Alanyl-L-Cystine can accumulate within plant cells and regulate osmotic potential. Under drought, salinity, and other stress conditions, it helps plants retain water, preventing dehydration-related damage and maintaining normal cellular physiological functions. This enhances plant adaptability to adverse environments.
Ⅲ.Promotion of Plant Hormone Balance
1. Influence on Hormone Synthesis
L-Alanyl-L-Cystine may participate in hormone biosynthesis or regulate the expression of genes involved in hormone production. For instance, it may influence the synthesis of growth-promoting hormones such as auxins and cytokinins, thereby regulating plant development processes such as root formation, germination, and stem and leaf growth.
2. Regulation of Hormone Signal Transduction
For plant hormones to function effectively, their signals must be transmitted to intracellular target sites through signal transduction pathways. L-Alanyl-L-Cystine may help regulate hormone signaling, enhancing plant cells' sensitivity to hormonal cues. This allows plants to respond more efficiently to hormone signals, finely controlling growth, development, and environmental adaptation.
Ⅳ.Improvement of Plant Nutritional Status
1. Enhancement of Nutrient Absorption Efficiency
L-Alanyl-L-Cystine can influence root growth and development, promoting a more extensive root system and increasing root-soil contact. This improves the plant’s absorption efficiency of essential nutrients such as nitrogen (N), phosphorus (P), and potassium (K). Additionally, it may participate in nutrient transport and distribution within plants, ensuring that nutrients are prioritized for rapidly growing tissues.
2. Promotion of Nitrogen Metabolism
The nitrogen element in L-Alanyl-L-Cystine serves as a supplementary nitrogen source for plants. It participates in nitrogen metabolism, facilitating the synthesis of nitrogen-containing compounds such as amino acids and proteins. This improves nitrogen utilization efficiency, playing a crucial role in plant growth and development.
