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Sieve cells are long, conducting cells in the phloem that do not form sieve tubes. The major difference between sieve cells and sieve tube members is the lack of sieve plates in sieve cells. [1] They have a very narrow diameter and tend to be longer in length than sieve tube elements as they are generally associated with albuminous cells. [4]
Callose gets synthesized after the sieve tube elements undergo damage and/or stress. The use of wound callose occurs when callose gets deposited following sieve element damage. [2] Wound callose is proven to first be deposited at the sieve plate pores, or the intracellular connections, where it then spreads to different regions. [2]
As a result, the concentration of sucrose increases in the sieve tube elements. This causes water to move into the sieve tube element by osmosis, creating pressure that pushes the sap down the tube. In sugar sinks, cells actively transport sucrose out of the sieve tube elements, first to the apoplast and then to the symplast of the sink.
These porous connections are called sieve plates. In spite of the fact that their cytoplasm is actively involved in the conduction of food materials, sieve-tube members do not have nuclei at maturity. It is the companion cells that are nestled between sieve-tube members that function in some manner bringing about the conduction of food.
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A sieve analysis (or gradation test) is a practice or procedure used in geology, civil engineering, [1] and chemical engineering [2] to assess the particle size distribution (also called gradation) of a granular material by allowing the material to pass through a series of sieves of progressively smaller mesh size and weighing the amount of material that is stopped by each sieve as a fraction ...
A variety of sieve sizes are available. The boundary between sand and silt is arbitrary. According to the Unified Soil Classification System, a #4 sieve (4 openings per inch) having 4.75 mm opening size separates sand from gravel and a #200 sieve with an 0.075 mm opening separates sand from silt and clay. According to the British standard, 0. ...
The diagram on the right shows: (a) Young specimens of M. chuni anchored to the muddy substratum by one single giant basal spicule (gbs). The body (bo) surrounds the spicule as a continuous, round cylinder. (b) The growth phases of the sessile animal with its GBS (gbs) which anchors it to the substratum and holds the surrounding soft body (bo).