Phloem
In vascular plants, phloem is the living tissue that carries organic nutrients (known as photosynthate), in particular, sucrose, a sugar, to all parts of the plant where needed. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Greek word φλοιός (phloios) meaning "bark". The phloem is concerned mainly with the transport of soluble organic material made during photosynthesis. This process of transportation is called translocation.
Structure
Phloem tissue consists of: conducting cells, generally called sieve elements; parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells; and supportive cells, such as fibres and sclereids.
Conducting cells (Sieve elements)
Sieve elements are the type of cell that are responsible for transporting sugars throughout the plant. At maturity they lack a nucleus and have very few organelles, so they rely on companion cells or albuminous cells for most of their metabolic needs. Sieve tube cells do contain vacuoles and other organelles, such as ribosomes, before they mature, but these generally migrate to the cell wall and dissolve at maturity; this ensures there is little to impede the movement of fluids. One of the few organelles they do contain at maturity is the smooth endoplasmic reticulum, which can be found at the plasma membrane, often nearby the plasmodesmata that connect them to their companion or albuminous cells. All sieve cells have groups of pores at their ends that grow from modified and enlarged plasmodesmata, called sieve areas. The pores are reinforced by platelets of a polysaccharide called callose.
Podcasts:
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Will.I.Am
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by Flema
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by Flema
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by Flema
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by Volume 10
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by Volume 10
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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by Flame
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Love Bullets (feat. Skylar Grey)
by: Will.I.AmLove will be the armor
Protect us from the pain
In our life
In our life
Even when the storm comes,
We'll stand out in the rain,
Watch it slide, live inside.
Here we stand against the world
You and I we rock the lullaby
Make me feel alive, cause the love will never day
Me put you long one,
Shot me down and we're gone,
Ain't no need to worry, don't call 911.
Bang-bang, a lot of bang-bang,
Shoot me with your love and got me feeling no pain.
Kill it, kill it baby with your love even, bang bang,
Baby, do it again.
So shoot me with your bullet, bullet, bullet,
Such a pretty bullet, bullet, bullet,
Go ahead and pull it, pull it, pull it,
Shoot me with your bullet, bullet, bullet.
So shoot me with your bullet, bullet, bullet,
Such a pretty bullet, bullet, bullet,
Go ahead and pull it, pull it, pull it,
Shoot me with your bullet, bullet, bullet.
Even if you're mad at me
And fighting all the time
It's alright, it's alright.
I would risk my sanity
I would lose my mind
For one night, for one night.
Here we stand against the world
You and I we rock the lullaby
Make me feel alive, cause the love will never day
Me put you long one,
Shot me down and we're gone,
Ain't no need to worry, don't call 911.
Bang-bang, a lot of bang-bang,
Shoot me with your love and got me feeling no pain.
Kill it, kill it baby with your love even, bang bang,
Baby, do it again.
So shoot me with your bullet, bullet, bullet,
Such a pretty bullet, bullet, bullet,
Go ahead and pull it, pull it, pull it,
Shoot me with your bullet, bullet, bullet.
So shoot me with your bullet, bullet, bullet,
Such a pretty bullet, bullet, bullet,
Go ahead and pull it, pull it, pull it,
Latest News for: phloem
Evolution of the JULGI–SMXL4/5 module for phloem development in angiosperms
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