Translocation | Biology for GCSE/IGCSE - Year 11 PDF Download

Translocation: Extended

• The end products of photosynthesis include sugars, primarily sucrose, and amino acids.
• These essential nutrients are conveyed throughout the plant via phloem tubes, which consist of living cells in contrast to xylem vessels that are composed of deceased cells.
• Phloem cells are interconnected end to end, featuring sieve plates in their cell walls that facilitate the smooth movement of substances from one cell to another.
• The process of transferring sucrose and amino acids through the phloem, from sites of production to areas of storage or utilization, is termed translocation.
• Transport within the phloem can vary, depending on the plant's growth stage or the time of year, with nutrients consistently moving from sources (production sites) to sinks (storage or usage areas).
• For instance, during winter when many plants lack foliage, phloem tubes may transport dissolved sugars and amino acids from storage organs to sustain respiration.
• In periods of growth like spring, roots serve as sources while various plant parts act as sinks for nutrients.
• Subsequently, in peak growth periods like summer, leaves, being the primary sites of photosynthesis, transform into sources, transferring sugars to roots for storage as starch until required.

Comparison between Xylem and Phloem Tissue Table

• Translocation through the phloem: This process involves the movement of sugars and other nutrients through the phloem tissue in plants to different parts of the plant, such as leaves, roots, and fruits.
• Comparison between Xylem and Phloem Tissue: Xylem and phloem are two types of vascular tissues in plants. While xylem transports water and minerals from the roots to the rest of the plant, phloem carries sugars produced during photosynthesis to various plant parts.