Translocation is the movement of organic substances made by the plant which are called assimilates. In plants, it refers to the processes of photosynthesis and the absorption of raw materials by which plants derive their nutrition. Examples of assimilation are photosynthesis, nitrogen fixation, and the absorption of nutrients after digestion into the living tissue.
The Products of Assimilation is Assimilates.
Sieve elements are specialized cells that transport sugars and other organic compounds throughout plants. They are the main conducting cells in the phloem, a tissue that transports organic compounds made during photosynthesis.
The function of companion cells is to support sieve elements by carrying out cell metabolism and regulation.
In translocation, the source is the part of the plant where nutrients are produced, and the sink is where they are needed or stored.
Sieve tubes are made up of elongated cells that are connected end-to-end in vertical rows. The cells are interconnected by perforations in their walls, called sieve plates. The sieve plates are groups of sieve areas, usually with larger pores than those on the lateral walls of the cell.
Sieve tubes are the conducting element of the phloem. Phloem is found in all vascular plants, including angiosperms (flowering plants) and gymnosperms (plants with seeds unenclosed in an ovary).
Sieve tubes are considered living cells without a nucleus because the nucleus of companion cells controls their functional activities.
The apoplast and symplast are two pathways in plants that transport water and solutes:
Apoplast - The extracellular space outside of plant cell membranes, including the fluid-filled cell walls of adjacent cells. The apoplast pathway is a non-living route, as the water solution moves in the spaces between cells and along the cell wall.
Symplast - The region enclosed by the cell membranes, within which water and solutes can diffuse freely. The symplast pathway involves protoplasts, which are found within the living cytoplasm cells.