Plants II Flashcards
(41 cards)
2 types of vascular plants
lycophytes and euphyllophytes
what kind of development for vascular plants and what kind of tissue?
apical development makes primary tissue
-seed plants make 2 tissue
lignin
gives wood strength
-plants can’t break it down
Primary tissue
develops from apical meristem and becomes primary plant body (roots, stem, leaves)
secondary tissue
- develops later within primary growth and thickens root and stem
- vascular cambium
3 offshoots from apical meristem
Protoderm –> epidermis (dermal tissue system)
Ground Meristem –> ground tissue (parenchyma, collenchyma, sclerenchyma)
Procambium –> primary xylem and phloem
xylem
water-conducting tissue made of tracheids and vessel elements
-lignified and has fiber
phloem
food-conducting cells made of sieve tube cells and companion cells
epidermis
outermost layer of cells of stem and leaves
-jigsaw puzzle pattern of epidermal cells
stomates + guard cells
regulate gas exchange and decrease water loss in epidermis
trichomes
above ground
-prevent water loss in stem and leaves
root hairs
below ground
-prevent water loss in roots
cortex and pith
primary ground tissues
- cortex is peripheral
- pith is central
arrangement of primary tissue
varies by location in plant
leaf: < o o o >
root / o o \
…… \ o o /
stem /…….o ….. o…… \
……… I o ……………..o I
………. .…. o…… o …./
Shoot anatomy
- where do lateral shoots come from?
- what are the layers of the shoot?
- where do leaves come from?
- what are the layers of leaves?
- axillary buds
- leaf primordium
apical meristem: Tunica (L1 and L2)
Initial layer of corpus (L3)
pith meristem - shoot apex
- epidermis, mesophyll, xylem/phloem
root function
anchors plant
aborbs water and nutrients
cortex in roots
has endodermis (innermost layer of cortex)
- endodermal cells in single layer with suberin-containing casparian strip
- strip is attached to plasma membrane and connects to casparian srips in adjacent cells
- strip blocks movement of water between cells –> water must move thru cell membrane to enter vascular cylinder in center
- as root matures, endodermis becomes sealed with suberin and water doesn’t move into vascular system anymore
Stele: definition and types
- arrangement of primary vascular tissue in stems and roots
- have changed over evolutionary time in dif. plant gps
- protosteles, euteles, alactosteles, siphonosteles
protostele
earliest arrangement observed in vascular plants
- solid core of xylem in center
- still observed in some seed plant roots
siphonostele
solid cylinders of vascular tissue with pith in center
-vascular tissue forms o or c
eustele
pith in center
vascular bundles in circle
-in eudicot stems and monocot roots
alactostele
scattered vascular bundles
in monocot stems
secondary growth
2 meristem 2 tissues
…………………………………………………………….._____ secondary X
X/P ————-vascular cambium ———/_____ secondary P
cortex ——— cork cambium_____________phelloderm
………………………………………………………………….\______cork
vascular cambium
- develops between 1 x/p
- makes 2 x/p
- as growth in diameter continues, pressure on peripheral tissue causes them to slough off
- cells appear stacked
- vascular rays = parenchymatous cells that conduct fluid
