plant transport systems + xylem

• Label transverse section of root

  A) cortex

  B) medulla

  C) phloem

  D) xylem

  E) endodermis

  
• Label the transverse section of a stem

  A) sclerenchyma

  B) collenchyma

  C) cortex

  D) xylem

  E) phloem

  F) medulla

  
• Label the tissues seen in a stem

  A) sclerenchyma

  B) phloem

  C) companion cell

  D) sieve tube

  E) cambium

  F) xylem

  
• Label the transverse section of a leaf showing tissue plan

  A) phloem

  B) xylem

  C) central midrib

  D) small vein in leaf lamina

  
• Label the transverse section of the xylem

  A) parenchyma

  B) empty lumen

  C) thick lignified wall of xylem vessel

  
• label longitudinal section of phloem

  A) sieve plate

  B) cytoplasm

  C) sieve tube

  D) companion cell

  
• label transverse section of phloem

  A) sieve plate

  B) companion cell

  C) parenchyma

  
• reasons for a transport system

  - metabolic demands: internal + underground parts do not photosynthesise -> need glucose + oxygen transported to them

  - size: need transport system to move substances from roots to topmost leaves

  - SA V ratio: small SA:V1
• woody dicots

  hard, lignified tissues + a long life cycle
• herbaceous dicots

  soft tissues + short life cycle
• xylem function

  - transports water + mineral ions up the plant

  - support
• parenchyma

  store food + tannin deposits
• tannin

  chemical that prevents herbivores from consuming the plant
• lignin

  polysaccharide that provides extra mechanical strength
• water functions

  - turgor (hydrostatic) pressure: provides hydrostatic skeleton to support stems + leaves

  - loss of water by evaporation: keep plants cool

  - transports mineral ions + products of photosynthesis in aqueous solutions

  - raw material for photosynthesis
• adaptations of root hair cells

  - microscopic size: penetrate easily between soil particles

  - large SA:V ratio

  - thin surface layer

  - concentration of solutes in cytoplasm: maintains water potential gradient between soil water + cells
• apoplast pathway

  movement of water through cell walls + intercellular spaces
• symplast pathway

  movement of water through cytoplasm + plasmodesmata
• vacuolar pathway

  movement of water through vacuole, cytoplasm + plasmodesmata