Shoot morphology Flashcards
similarities and differences w roots and shoots
-Both have cortex- makes up body of organs in shoots
-stem has cuticle, the waxy layer. Would disrupt water absorbtion in roots
vascular tissue
transporting consisting of xylem and phloem
procambium
produces primary xylem and phloem
xylem consists of
1)vessel elements
2)traicheids
-consists of fibers and parenchyma cells
vessel elements
-lack end walls
-continuous pipeline for transport
-single cells
traicheids
-single cells
-elongated with tapered ends
pit pairs
-located in secondary wall region where there is no secondary wall
-only middle lamella and primary cell walls called pit membrane that water flows through
vessel elements and traicheids
-both hollow and non living,
have thickened secondary walls where lie pit pairs(big ahh holes in wall)
-accompanied by bordered pit pairs
what are bordered pit pairs and how do they work
-have secondary wall projections over pit area and a central region called Torus (seals off elements with low pressure)
-when there is a unequal pressure(airbubble) torus gets sucked infront of the element with lower pressure, sealing it.
water movement in
traicheid
traicheid flows between adjacent traicheids, vertically or laterally through the pit pairs
Gymnosperm vs angiosperm
gymnosperms only have traicheids
angiosperms have both
Phloem
-transport tissue
-source tissue to sink tissue
leaf to roots generally
-can go up and down though
-sieve tubes and companion cells
sieve tube cells
in phloem and contain cytoplasm but no nuclei, ends form a plate with holes
companion cell
closely connected to sieve tubes as the nucleus of the companion cell maintains both cells
Phloem transport
food(sucrose) in phloem, flows any direction
sink tissues may be reversed(winter:roots up, summer: leaves down)
