{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Transport_in_stems - Ioana Dobre Transport in stems-Xylem...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Ioana Dobre Transport in stems -Xylem transports water and minerals to leaf and is essentially passive Phloem = tissue made up of conducting tubes called sieve tubes - have crossed walls in them, transport sugary sap up from the leaves to any growing or non- photosynthetic tissue. It is a circulatory system - energy is derived from companion cell *huge number of mitochondria* --> the engine that enables transport The dicot stem (in class diagram) - Epidermis – waxy layer + secondary metabolites for protection - Collenchymas has fortified cell walls for protection. Provides cylindrical support - Parenchyma – relatively undifferentiated cells - Pith – extremely large cells that may collapse - Vascular bundle ( xylem, phloem and procambium) Phloem and Sugar transport - Sieve tubes have little structure except transcellular strands, crosswalls - Companion cells provide energy for sap transport through abundant mitochondria - Transport is from source ( leaves) to sink (growing or non-photosynthetic tissue) Phloem anatomy - the pressure inside the sieve tubes is very high. Hard to handle this type of tissue ( very sensitive) -no mitochondria/nucleus/chloroplasts inside the sieve tube. therefore companion cells are highly differentiated P ressure flow mechanism (in class diagram) -
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}