Lecture: Secondary Meristems Flashcards
secondary growth uses what 2 meristems?
vascular cambium and cork cambium
the vascular system of monocots and herbaceous dicots are __
closed
where is the vascular cambium located?
between xylem and phloem
how many cells thick is the vascular cambium?
1
initials are initially dormant and are under ___ control
hormonal
to add girth, there must be a complete __ of cells
ring
what would happen if there was not a complete ring of cells for growth in girth?
grow unevenly
in a vascular bundle, the vc is called the
fascicular cambium
what is the gap between fascicles called?
interfascicular gap
how is a complete ring made in a eustele?
the gaps between bundles form the interfascicular cambium which connects to fascicular cambium to form complete ring
the Vc initials divide ___
periclinally
all cells produced by secondary meristems are __ tissues
secondary
___ and ___ get pushed towards the outside as more cells are made
phloem and vc
to increase surface area, cells must be added by __ divisions
anticlinal
increased girth raises the issue of needing to transport ___
laterally
describe shape of fusiform initials
vertical, long and narrow
how do fusiform initials grow, and what do they produce?
periclinally; secondary xylem and phloem
describe shape of ray initials
horizontal, long and narrow
what way do ray initials divide and what do they produce?
anticlinally; parenchyma that make rays
what is the newest wood called? Is it functional?
sapwood, functional
what is the oldest wood called? Is it functional?
heartwood, non-functional
what causes annual rings?
temperate seasonality, cells get smaller in the winter which makes thin rings separating the thicker summer rings
the epidermis is replaced by
derivatives of phellogen
the cork cambium originates
under epidermis in cortex
the cork cambium divides
periclinally
what is cork made of?
dense dead cells, suberin, wax, lignin
what is a special feature of cork?
water and gas proof
what is the phelloderm made of?
living parenchyma
what is the tearing point for bark?
vc
what is included in bark?
periderm and 2’ phloem
what is outer bark?
periderm
what is inner bark?
secondary phloem
