Leaves Flashcards
what is the shoot
combination of the stem and the leaf
multicellular part of the plant containing vasculature
what is the shoot responsible for
conductance of water, minerals and photosynthesis
photosynthesis
gas exchange
what is the stem
multicellular structure supporting the leaves
what does the stem consist of
epidermal tissues
ground tissues
vascular tissues
what are the functions of the stem
support
cinductance
what supports leaves
the stem
helps maximize exposure to leaf surfaces to sunlight
what is conductance in the stem
water transported from the roots to the leaves through the xylem and the stem
sugar produced in the leaves transported through the phloem
what are 3 cell types in the stem
dermal tissue
ground tissue
vascular tissue
what are 3 cellular organizations in stems
woody
monocot
dicot
characteristic of woody stems
vasc is organized in a ring like structure called a vasc cylinder
characteristic of dicot herbaceous stem
discreet vasc bundles collected into a ring
what is a vasc bundle
xylem and phloem together
characteristics of monocot herbaceous stems
scattered vascular bundles throughout the ground tissues of the stem
what are the 3 types of ground tissues in stems
parenchyma
collenchym
sclerenchyma
how can ground tissue types differ in stems
cell wall thickness and types function location in the plant
characteristics of sclerenchyma cells in stem
dead at maturity
well developed primary and secondary cell walls
what is function of sclerenchyma cells in stem
very firm structural support
plant fibers
characteristics of collenchyma cells in stems
alive at maturity
primary cell walls vary in thickness
function of collenchyma cells in stems
structural support with some flexibility
characteristics of parenchyma cells in stems
alive at maturity
thin primary cell walls
functions of parenchyma cells in stems
photosynthesis and respiration
storage
growth
what directions can stems grow in
length
width
where does stem lengthen
primary growth
what are sites of primary growth
apical meristem
intercalary meristem
what is apical meristem
site of all primary cell growth in the plant
how does growth take place in apical meristem
through successive mitosis
what are the 3 mersitematic tissues in apical meristem
protoderm
procambium
ground mersitem
what are the 3 growth stages of the stems length
cell division
cell elongation
cell maturation
what happens in cell division of stem length
production of leaf primordia and buf primordia
what happens in cell elongation of stem length
xylem formation begins
cell elongate
what happens in cell maturation of stem length
maturation of vasculature
what is protoderm
produces dermal tissues
what is procambium
produces vasc tissues
what is ground meristem
produces ground tissues
what is leaf primordia
initial leaf tissue
what is bud primordia
a new bud
what are apical buds
terminal bud, the tallest apical mersitem
what are lateral buds
found near a corresponding leaf
grows anywhere on plant
what are phytomeres
units of growth produced by leaf and bud primordia
what do phytomeres consist of
leaf
node
internode
lateral bud
what is a node
section on the stem where leaves, buds or roots emerge
what is an internode
length of stem between nodes
what is the intercalary meristem
soot meristem which contributes to the lengthening of the internodal space
where are intercalary meristems found
grasses
equistems
what is secondary growth
the widening of stems and roots
what are the sites of secondary growth
vascular cambium
cork cambium
where is the vascular cambium
between the xylem and the phloem
what does vascular cambium produce and where
- xylem, inside vasc cambium towards center of stem
- phloem, exterior of vasc cambium towards the bark
what is the role of the cork cambium
adding new dermal cells that can contain all the new growth
aka produces crok
what is cork
very thick secondary cell walls
dead at maturity
what is the leaf
multicellular structure containing vasculature
primary site of photosynthesis
what does the leaf consist of
epidermal tissues
ground tissues
vascular tissues
what are the functions of the leaf
support
conduct
how is vasc tissue organized in leafs
into veins: parallel or netted
what are important structures unique to leaves
palisade mesophyll
spongy mesophyll
what are structures concentrated on leaves
stomata
guard cells
what is mesophyll in leaf
main ground tissue
what does leaf mesophyll consist of
parenchyma
what are 3 types of cellular organization in leaf mesophyll
palissade
spongy
wreath like
characteristics of palissade mesophyll
tall narrow parenchyma cells tightly packed behind the dermal cells
main site of photosynthesis
on all C3 plants not C4
characteristics of spongy mesophyll
loosely arranged parenchyma cells
air between cells
contains vasculature
in all C3 photosynthesis plants not C4
what happens to te leaf because of sun and shade
palissade and spongy mesophyll cells change their orientation and concentration depending on the relativr light in the environment
characteristics of sun leaves
maximize photosynthesis
thicker cuticle to minimize water loss
taller palissade cells to take advantage of increased light
characteristics of shade leaves
minimize limitiation of low light
use less energy
more spongy mesophyll cells to allow more gas in the leaf interior so light penetrates deeper in the leaf
characteristics of wreath like mesophyll
concentrate around the vasc of the leaf
main site of photosynthesis in C4 plants
concentrates CO2 into malate
not in C3 plants
characteristics of collenchyma cells in leaves
structural support function
mainly along the midvein of the leaf
what are leaf dermal tissues specific adaptations
Desiccation protection
(cuticle, stomata and guard cells)
controlling photosynthetic rate
pathogen protection
what is the cuticle
waxy layer secreted by plants to cover dermal cells
what are stomata
pore for gas exchange of the surface of the leaf
necessary for efficient movement of water through vasculature
what are guard cells
open and close stomata
how does leaf dermal tissue control photosynthetic rate
- transparent epidermal cells maximize access of sunlight to palissade mesophyll cells
- movement of palissade parenchyma
- accessory pigments absorb photons and release as fluorescence to prevent overloading reaction center
what are trichomes
extension of dermal tissues
hair like form on leaves
theoretically used for pest deterrence
what are 2 classes
glandular
unicellular/pluricellular
what are unicellular trichomes
single elongated epidermal cell
what are pluicellular trichomes
several cells forming a simple elongated structure
what are glandular trichomes
last cell at the tip pf the trichome
chemical deterence
contain substances in cell vacuole for defense
