WebbFigure 30.36 Phloem is comprised of cells called sieve-tube elements. Phloem sap travels through perforations called sieve tube plates. Neighboring companion cells carry out metabolic functions for the sieve-tube elements and provide them with energy. Lateral sieve areas connect the sieve-tube elements to the companion cells. WebbThe mature sieve tube lacks a nucleus, but while functional contains cytoplasm. Sieve tubes may often be detected by recognition of the callus pads, which show typical staining reactions. 1. ... This leads to a fall in the hydrostatic pressure at that location in the sieve tube, which serves to bring more phloem sap toward the active Sink.
Plant transport tissues - xylem and phloem - BBC Bitesize
WebbThe function of phloem tissue in a plant is to:. Transport organic compounds (assimilates), particularly sucrose, from the source (eg. leaf) to the sink (eg. roots).The transport of … Webb1 maj 2024 · The sieve tube cells have no nuclei hence avail more space for translocation. The companion cells are highly metabolic to sustain needs of the sieve tube. Phloem … craftsman 44811 ratchet
Sieve tube element - Wikipedia
WebbPhloem structure function In the phloem, tubular cells assemble into so-called sieve tubes which form a continuous microfluidics network. In this network, the products of … Webb8 maj 2024 · Protophloem sieve tube cells differentiate close to the meristem, whereas metaphloem sieve tube cells and companion cells start differentiating further away from the meristem. However, unlike the protophloem cells, which are only functional in the root tip, the metaphloem sieve tubes and companion cells stay functional in the … Webb25 nov. 2024 · The structure of the sieve element is an elongated and narrow form. These cells are connected together to form the phloem sieve tube structure. The two main types of sieve elements include the sieve member in angiosperm and the more primitive sieve cells in gymnosperms. These two types are both derived from a common ‘mother cell’ … division 2 heartland 2022