The transport of sugars from the source to the sink in plants is crucial for growth and is regulated by environmental factors. Sucrose is the primary sugar transported in the phloem, along with polyols and raffinose family oligosaccharides. Phloem transport is influenced by various abiotic and biotic factors, including water and salt stress, mineral deficiency, CO₂, light, temperature, and pollutants. These factors can alter the distribution of sugars among sinks, affecting phloem function and overall plant productivity. Biotic interactions, such as those with aphids, fungi, and viruses, also impact crop productivity. Recent studies have identified some sugar transporters involved in these interactions. The phloem transport mechanisms involve active loading, where sucrose is concentrated in the sieve element-companion cell complex, and polymer trapping, where sucrose is converted to larger molecules. The transport of sugars through the phloem is primarily driven by mass flow, with hydrostatic pressure differences between the source and sink. Sucrose transporters (SUTs) play a key role in regulating sugar fluxes. Environmental factors can affect the source-to-sink transport of sugars by altering the availability of sugars for export, the demand for sugars by sinks, and the efficiency of transport pathways. Abiotic factors such as water deficit, mineral deficiency, and salt stress can impact sugar metabolism and phloem loading, leading to changes in sugar concentrations and transport efficiency. Biotic factors, such as pathogens and pests, can also disrupt sugar transport and affect plant productivity. The effects of environmental cues, such as water deficit, mineral deficiency, and light, on sugar transport are significant, with water deficit affecting photosynthesis and sugar metabolism, and mineral deficiency altering resource allocation. The role of sucrose transporters in drought and salinity tolerance is an area of ongoing research. The effects of low temperatures on phloem sugar transport vary between species, with symplastic loaders being more sensitive to cold. Increased CO₂ levels can enhance photosynthesis and carbohydrate production, leading to increased sucrose transport and growth. However, high CO₂ levels can also have negative effects on plants, such as reduced protein accumulation in wheat grains. The effects of pollutants like cadmium on phloem sugar transport are not well understood, but some studies suggest that cadmium can affect sugar transport and accumulation. Overall, environmental factors play a critical role in regulating the source-to-sink transport of sugars in plants, influencing growth, development, and productivity.The transport of sugars from the source to the sink in plants is crucial for growth and is regulated by environmental factors. Sucrose is the primary sugar transported in the phloem, along with polyols and raffinose family oligosaccharides. Phloem transport is influenced by various abiotic and biotic factors, including water and salt stress, mineral deficiency, CO₂, light, temperature, and pollutants. These factors can alter the distribution of sugars among sinks, affecting phloem function and overall plant productivity. Biotic interactions, such as those with aphids, fungi, and viruses, also impact crop productivity. Recent studies have identified some sugar transporters involved in these interactions. The phloem transport mechanisms involve active loading, where sucrose is concentrated in the sieve element-companion cell complex, and polymer trapping, where sucrose is converted to larger molecules. The transport of sugars through the phloem is primarily driven by mass flow, with hydrostatic pressure differences between the source and sink. Sucrose transporters (SUTs) play a key role in regulating sugar fluxes. Environmental factors can affect the source-to-sink transport of sugars by altering the availability of sugars for export, the demand for sugars by sinks, and the efficiency of transport pathways. Abiotic factors such as water deficit, mineral deficiency, and salt stress can impact sugar metabolism and phloem loading, leading to changes in sugar concentrations and transport efficiency. Biotic factors, such as pathogens and pests, can also disrupt sugar transport and affect plant productivity. The effects of environmental cues, such as water deficit, mineral deficiency, and light, on sugar transport are significant, with water deficit affecting photosynthesis and sugar metabolism, and mineral deficiency altering resource allocation. The role of sucrose transporters in drought and salinity tolerance is an area of ongoing research. The effects of low temperatures on phloem sugar transport vary between species, with symplastic loaders being more sensitive to cold. Increased CO₂ levels can enhance photosynthesis and carbohydrate production, leading to increased sucrose transport and growth. However, high CO₂ levels can also have negative effects on plants, such as reduced protein accumulation in wheat grains. The effects of pollutants like cadmium on phloem sugar transport are not well understood, but some studies suggest that cadmium can affect sugar transport and accumulation. Overall, environmental factors play a critical role in regulating the source-to-sink transport of sugars in plants, influencing growth, development, and productivity.