Vascular Tissue Flashcards
- The transport system of the plant
- Comprised of three components:
Exterior Interior
<– phloem cambium xylem –>
vascular tissue
Organization of vascular bundles is variable:
- form a complete _____ in the stem
- arranged as a _____ of bundles (dicot)
- vascular bundles __________ throughout the stem (monocot)
ring
circle
distributed (scattered)
VASCULAR TISSUE
- Normally localized towards the _______ of the vascular bundle
- Primary function is to distribute photosynthate (_________) from leaves (source) to the rest of the plant
outside
fixed carbon
PHLOEM
phloem is composed of 2 major cell types
a. _____________
- responsible for transport but lack a nucleus
- elongated cells with porous connections between the ends of cells (sieve plates)
b. _____________
- support the activity of the sieve tube
a. sieve tube members
b. companion cells
- to provide a source of new cells for growth of the vascular system
- this is a ____________
- ___________ is a thin layer of undifferentiated cells between the phloem and xylem
- After division, this can produce either phloem or xylem cells
- essential for radial expansion of the stem
meristematic tissue
Cambium
VASCULAR CAMBIUM
- Normally localized towards the INSIDE of the vascular bundle
- required for transport of water and nutrients from root throughout the plant
- Xylem cells die after _________
- Xylem contains several cell types
- _______, long and thin
- _______, short and fat
differentiation
Tracheids
Xylem vessels
XYLEM
- Cell walls of these cells are thickened for strength
- Rings of _______ provide reinforcement
- Water and nutrients are moved through xylem vessels and tracheids arranged end to end
- __________ provide structural support and are an important component of hardwoods
- __________ are primary component of soft woods including pines
lignin
Xylem fibers
Tracheids
XYLEM
- Innermost tissue of the stem
- Comprised of undifferentiated _____________
- Can function as a ________, for example in sugar cane
- May be _____________ in
many woody plants
parenchyma cells
storage tissue
lost or reduced
PITH
STEM STRUCTURE
EPIDERMIS
- epidermal
- guard cells
CORTEX
- parenchyma
VASCULAR SYSTEM
- phloem
- cambium
- xylem
PITH
- parenchyma
STEM GROWTH
- primary growth
- secondary growth
- new cells produced at the root tips and shoots
- increase in stem length
primary growth
- increase in stem width
✓ ______________: produces tissue and increases thickness
✓ ______________: produces outer covering of stems
vascular cambium
Cork cambium
SECONDARY GROWTH
formation of wood
wood
sapwood
✔ layers of xylem produced year after year
✔ resulted from the older xylem not conducting water (heartwood)
✔ becomes darker with age
wood
surrounds the heartwood
sapwood
formation of bark
- All the tissues outside the vascular cambium
- Consists of outermost layers of dead cork
- Function: waterproof
Stems: Internal Anatomy (Wood)
- bark
- heartwood
- sapwood
old, inactive secondary phloem
bark
old, inactive secondary xylem
heartwood
new, active secondary xylem
sapwood
- Lack secondary growth - because plants only live one year/growing season (annuals)
- Stems remain soft and flexible
- Buds lack protective scales (don’t need to survive harsh conditions)
herbaceous stems
- Plants living and growing over multiple seasons have secondary growth (xylem, phloem) increasing diameter of the stems
- This is due to the ____________ which gives rise to the secondary xylem and phloem
vascular cambium
WOODY STEMS
specialized stems
stolon
rhizome
tuber
bulb
section of a bulb
volubilate twining
stems that grow aboveground:
- tendrils
- searcher shoots
- stolons/runners
- thorns/spines
- cladodes/cladophylls
- culms
- succulent stems
