Term Test 2 Flashcards
1
Q
what is ground tissue?
A
-tissue that is not dermal or vascular
-can be used for photosynthesis, storage, and support
2
Q
what is the cortex
A
ground tissue found between the dermal and vascular tissue
3
Q
what is the pith
A
ground tissue in vascular cylinder
4
Q
what is parenchyma
A
-general purpose cells of the plant that are alive at maturity
-most common type
-least specialized
-can assume various shapes
-used for photosynthesis, storage, and structure
5
Q
what is collenchyma
A
-provides flexible support and is alive at maturity
-usually elongated
-can grow into various shapes
-“glue”
-lack secondary walls but have irregular thickening of primary cell walls
-plants produce more collenchyma cells in response to mechanical stressors such as wind
6
Q
what is sclerenchyma
A
-provides rigid support with lignin reinforced secondary walls and is dead at maturity
-“hard”
-abundance of sclerenchyma associated with increased plant size
-found in regions where growth has stopped and flexibility is not required
-two types: fibers and sclereids
7
Q
what are fibers
A
-type of sclerenchyma cell
-elongated cells with thick secondary wall reinforced with lignin
-length provides flexibility
-clustered in groups
-found in stems and tree trunks
-important in the production of cloth and paper
8
Q
what are sclereids
A
-type of sclerenchyma cell
-very in shape and are often cubical or spherical
-astreosclereids “star” shaped fills in air spaces
-have lignin in secondary walls
-found in nutshell and fruit pits
9
Q
plant stem functions
A
-stem and leaves together as known as a shoot
-conduct water, minerals, and organic molecules between roots and leaves
-support the weight of leaves
-move leaves towards light and away from the shade
-withstand wind and other mechanical stressors
-storage and reproduction and specialized stems
10
Q
what are meristems
A
-small populations of rapidly proliferating (dividing) cells that produce all of the mature organs of a vascular plant
11
Q
stem growth
A
-can grow in length by cells dividing below growing point by the shoot apical meristem
-stems can grow outwards, forming leaves, flowers, and branches from meristems in axillary buds
12
Q
the shoot apical meristem
A
-located at primary stem tip
-increases stem length through cell division
-dormant before growing season
-often protected by bud scales and leaf primordia (embryonic leaves)
13
Q
features of a plant stem
A
-internode; the space between leaf attachment points
-leaves are attached to stems at nodes
-dormant axillary buds located between the stem and the leaf petiole become branches, leaves, or flowers
-stipules are paired, leaf-like appendages at base of leaf
14
Q
what are rhizomes
A
-specialized stem
-horizontal stems that grow underground and have long to short internodes
15
Q
what are tubers
A
-specialized stems
-underground stems that store food (potato)
-“eyes” are nodes (axillary buds)
16
Q
what are tendrils
A
-specialized stems
-used for fastening to surfaces
17
Q
what are stolons (runners)
A
-specialized cells
-horizontal stems that grow above ground and have long internodes (strawberry)
-used in vegetative reproduction
18
Q
what are bulbs
A
-specialized stems
-large buds with fleshy leaves attached to short stem (onion)
19
Q
what are corms
A
-specialized stems
-resemble bulbs
-almost entirely made up of stem tissue with papery leaves
20
Q
what are cladophylls
A
-specialized stems
-flattened leaf like stems (cactus)
21
Q
vascular tissue patterns of stems
A
-variation exists in the arrangement of ground (pith and cortex) and vascular tissue (stele) in primary stems
22
Q
what is the protostele arrangement
A
-present in earliest plants
-solid xylem core
-phloem surrounds xylem
-some SVP have the protostele arrangement
23
Q
what is the siphonostele arrangement
A
-evolved from protosteles
-tubular xylem and phloem
-pith center
-common in ferns
24
Q
what is the eustele arrangement
A
-discrete vascular bundles of xylem and phloem
-found in dicots and gymnosperms
25
what does the stele of monocot angiosperms look like
-called atactostele
-vascular bundles scattered throughout the ground tissue
-distinct cortex or pith not evident
-variation of a eustele
26
vascular bundles of atactostele stems
-typical monocot vascular bundle consists of two large vessels with several smaller ones, an air space, sieve tubes, and companion cells
-bundle is surrounded by schlerenchyma sheath
27
dicot angiosperms leaves
-broad leaves
-branched reticulate veins
-veins usually attached to stem via a petiole
28
monocot angiosperm leaves
-narrow leaves
-parallel primary veins
-sessile (direct) attachment to stem
-leaf sheath is wrapped around stem
29
dicot flowers
-primitive flowers
-flower parts in multiples of 4 or 5
30
monocot flowers
-advanced flowers
-flower parts in multiples of 3
31
dicot stems
-eustele with loose ring
32
monocot stems
-atactostele
33
dicot roots
-tap root system
-x shape in center surrounded by circle
34
monocot roots
-fibrous root system
-circular arranged tissue
35
dicot vascular cambium
-vascular cambium and cork cambium can be present (primary and secondary growth)
36
monocot vascular cambium
-absent
-predominantly primary growth
37
what is primary growth?
-increase in shoot and root length by cellular division of the apical meristem
-meristems are present in all plants
38
how primary growth works
-meristems are small populations of rapidly proliferating cells that produce all of the mature organs of vascular plants
-roots and stems grow in length by cells dividing below growing point in the shoot apical meristem and above the root apical meristem
-stems can grow outwards, forming leaves, flowers, and branches from meristem in axillary buds
-roots can also branch from primary root lateral roots formed out of pericycle
39
what are initials
-cells of the meristem
-totipotent; capable of giving rise to any cell type
40
what is differentiation
-maturation of cell to a specific function
41
structure of woody branch undergoing wintering
-bundle scars; mark the vascular tissue within leaf scars
-bud scale scars; branch was originally formed from an axillary bud
-deciduous trees and shrubs lose all leaves annually
-after leaves fall they have dormant axillary buds with leaf scars below
42
primary root growth
-root apical meristem resides in quiescent center of root tip
-primary roots form "branches" called lateral roots which will have their own root apical meristem
43
what is secondary growth
-increase in girth generated by cell divisions of lateral meristems
-observed in both stems and roots of woody plants
-all gymnosperms have secondary growth
-20% of dicots
-5% of monocots
44
where do lateral meristems form
-in regions of maturation in stems and roots that have completed growth in length
-cylindrical and allow radial expansion
45
why is secondary growth needed
-increase conduction and support
-replace old tissues so do not have to maintain over hundreds of years
46
function of xylem and phloem
Xylem
-water conducting tissue
-root to shoot
Phloem
-metabolite conducting tissue
-shoot to root
47
secondary xylem and phloem
-same function as primary tissue
-secondary xylem tends to have thicker walls due to increase in lignin content
48
what is vascular cambium
-secondary xylem (wood)
-secondary phloem (bark)
49
what is cork cambium
-cork (bark)
-phelloderm (bark)
50
what is dedifferentiation
-derivative cells returning to initial cells
-hormones signal dedifferentiation even in mature tissue cells
-observed in vegetative propagation
-cambium cells are derived from dedifferentiated cells
51
vascular cambium in stems
-forms from dedifferentiated cortex and procambium
-produces secondary xylem and phloem in between primary xylem and phloem
52
what is auxin hormone
-a hormone in dicot and conifer stems that signal the formation of vascular cambium
53
what it fusiform initials
-cells derived from residual procambium cells located between primary xylem and phloem
54
what is ray initials
-arise from parenchyma cells or cortex (ground tissue) between vascular bundles
-not in gymnosperms
55
amount of secondary growth in stems
-more secondary xylem is produced than secondary phloem
56
what is wood
-secondary xylem
-consists largely of dead cells, tracheids, or vessel members
-highly lignified
-only the more recently formed layers of secondary xylem conduct water and minerals
-primary and older secondary xylem become inactive
57
hardwood
-in dicots
-xylem are made of fibers and vessels that are harder and have more lignin
58
softwood
-in conifers
-xylem consists primarily of tracheids which are softer and have less lignin
59
secondary phloem
-only more recent layers of secondary phloem conduct photosynthetic products
-primary and older secondary phloem become stretched and broken as vascular cambium push them outwards
60
growth patters
-yearly growth of xylem forms rings
-size of cells in rings varies with the season
-small cells in late summer (summerwood/late wood)
-large cells in the spring (springwood/early wood)
61
what is dendrochronology
-information gathered from tree rings
-tree rings have information about the tree age
-rings can show climate conditions
-rings can show historical events (abiotic such as fires or biotic such as disease)
-stress = less growth
62
what is heart wood
-older
-non conducting rings of xylem in the center of the trunk or root
-usually darker than sapwood
63
what is sapwood
-outer xylem rings
-still conduct water and minerals
64
what does parenchyma produce
-antibacterials and antimicrobial compounds
65
what are antimicrobial compounds
-resin
-pines and nonflowering plants have resin that flow through resin canals, secondary phloem and xylem, periderm, and leaves
66
secondary growth in monocot stems
-lack vascular cambium
-lack true secondary growth
-increase in girth of stem referred to as anomalous thickening of ground tissue
-no annual growth rings
67
cork cambium (phellogen)
-two types of dermal tissue; periderm and epidermis
-during secondary growth cork cambium replaces epidermis and cortex with periderm
68
what is cork
-phellem
-forms to the outside of the cork cambium
-consists of dead cells when mature
69
what is phelloderm
-forms to inside and consists of a thin layer of living parenchyma cells
70
bark structure
-periderm
-consists of all tissues external to the vascular cambium
-thinner than woody portion of stem
-cork cambium cannot grow in diameter and must reform inside old one
-cork cells enlarge and become impregnated with suberin
-two distinct regions: inner and outer
71
inner bark components
-living secondary phloem
-vascular cambium
-inner most cork cambium
-any remaining cortex
72
outer bark components
-dead tissue
-includes dead secondary phloem and all layers of periderm outside the most recent cork cambium
73
bark function
-essential for tree viability
-inner bark carries sugar and other organic molecules
-outer bark provides protection from abiotic and biotic stress
-cork cambium forms protective layers of tissues preventing water loss and infection by pathogenic organisms and predation
74
gas exchange in bark
-bark needed for protection but must also allow gas exchange
75
what are lenticles
-small openings in outer bark of stems and roots that allow gas exchange in tissue blocked by suberin coated cork cells
76
what is latex
-antimicrobial
-10% of flowering plants produce latex
-milky substance that blocks entry of pathogens and contains compounds with growth inhibitory properties
-deters insect and animal predators
-produced in vessels or special cells called laticifers
-network is not as visible as resin canals
-produced close to surface to be released upon injury
77
mature dicot leaves
-petiole
-flattened blade
-network of vascular bundles
-stipules at base of petiole
78
patterns of veins in leaves
Parallel
-in monocots and gymnosperms
Netted or Reticulate
-in dicots and ferns
79
what are stipules
-paired, leaf-like appendages at base of leaf
80
what is phyllotaxy
-arrangement of leaves on stem
-leaves are attached to nodes in a programmed pattern
81
what are the 3 patterns of phyllotaxy
1. alternate
-one leaf per node
2. opposite
-two leaves per node
3. whorled
-three or more leaves at a node
82
how is leaf phyllotaxy determined
-leaf primordia form from meristem in pattern that determines phyllotaxy of mature organs
83
what is abscission
-dropping of leaves seasonally
-occurs as a result of changes in abscission zone near base of petiole
84
how does abscission work
-protective layer of cells coated and impregnated with suberin, to seal off leaf scar
-separation layer of pectins in the middle lamella are broken down my enzymes at petiole and stem border
85
what are the tissues at make up leaves
1. epidermal tissue
-provides protection and gas exchange
2. mesophyll tissue
-the ground tissue that carries out photosynthesis
3. vascular tissue
-forms veins to transport organic molecules, water, and minerals between leaves and rest of the plant
86
leaf epidermis
-single layer of cells covering the entire surface of the leaf
-devoid of chloroplasts
-coated with cuticle and surface waxes provide protection from water loss, light radiation, and pathogen attack
-the surface waxes also serve as a semi-permeable barrier and regulate gas exchange and evaporation of water
-trichome hairs control moisture loss and predation
-waste materials may accumulate in epidermal cells
87
what are trichomes and their purpose
-uni or multi cellular outgrowths of the epidermis
-primary function is plant defence especially against insects
-can also be glands secreting essential oils
88
what do gland trichomes release
-essential oils
-prevent predation
-act as insect repellant and antimicrobials
89
what are stomata
-allow gas exchange
-lower epidermis has thinner layer of cutin and is perforated by numerous stomata
-more sophisticated than lenticles
-can open and close with turgor pressure of guard cells
90
mesophyll in leaves in dicots
-two types
-both types involved in photosynthesis and thus contain chloroplasts
1. palisade mesophyll
-elongated cells usually located immediately below the upper epidermis (tightly packed)
2. spongy mesophyll
-cells are located below this layer and are loosely packed and have air spaces to allow carbon dioxide diffusion
91
leaves in monocots
-do not have differentiated palisade and spongy layers
often have bulliform cells flanking the central vein
-bulliform cels partly collapse under dry conditions causing leaf to fold reducing transpiration
92
specialized leaves for storage
-succulents have modified leaves for water storage
93
specialized leaves for defence
-spines
-reduce leave surface and water loss
-protect from herbivory
94
specialized leaves (bracts)
-floral leaves
-at bases of flowers or flower stalks
95
specialized leaves for insect trapping
-grow in nitrogen and mineral deficient soils such as swampy area and bogs
-obtain nutrients from digesting insects
96
specialized leaves for nutrients and reproduction
-mother of thousands
97
what is the function of roots
-water absorption
-vascular transport
-anchoring
-provide storage
-aide in asexual reproduction
-produce hormones and secondary metabolites that regulate plant development and communication
98
how do roots grow
-embryo radicle emerges immediately upon germination and the primary root forms
-from radicle to primary root, secondary roots form
-root systems can be fibrous or taproot
99
fibrous root system
-found in monocots
-large number of fine roots of similar diameter
-adventitious roots form from stem or leaf
-lateral roots form from adventitious roots
-typically shallow
-increased number of roots lead to improved water acquisition; not drought tolerant
-stabilize soil, decrease erosion
100
monocot roots
-core of parenchyma cells (pith) surrounded by rings of xylem and phloem
-pith cells arise from procambium, not ground meristem
101
tap root systems
-found in dicots and gymnosperms
-thick tap root
-from tap root thinner secondary root (lateral roots) form
-tap roots are deep in the soil
-not as effective at water absorption but they allow plants to survive extreme drought conditions
-can be used for water or food storage
102
dicot roots
-"arms" of xylem with phloem in between
-no pith
103
root specialization for water storage
-can help plants survive in arid environments
-only in tap roots
104
root specialization for food storage
-store starch in their roots
-storage cells are increased number of parenchyma formed by anomalous secondary growth
105
external root structure
1. Lateral roots
-form from pericycle in region of root that has completed primary growth
2. root hairs
-epidermal cell extensions
-aid in absorption of water and nutrients
3. root cap
-mass of parenchyma cells that cover each root tip which protect the meristem
-protect tissues from damage as the root grows
-first cell layer has a waxy cuticle
-secretes mucilage that aides in growth through soil and provides medium for beneficial bacterial
-amyloplasts in tip act as gravity sensors
106
root hairs
-adhere to soil particles in order to compete for water and nutrients
-increase total surface area of absorption
-in growing roots, new root hairs are continuously formed with older root hairs dying off
-root hairs are always in the zone of maturation near root cap
107
chemical protection in roots
-gymnosperms have resin canals
-dicots have latex in roots
-flavonoids with antifungal, antiviral, and antimicrobial properties accumulate in root cell vacuoles
108
root permeability and protection
-to help in absorption, epidermal root hairs do not have a cuticle
-without cuticle the cell walls are permeable to water, solutes, and potentially microorganisms
-to protect the root hairs roots impregnate key cell layers of cortex with suberin and lignin to restrict water and solute movement
-casperian strips are deposits of lignin and suberin in the radial primary cell wall and middle lamella of endodermis and exodermis
109
what is the exodermis
outermost cell layer of cortex
110
what is the endodermis
innermost cell layer of cortex
111
what are passage cells
-cells that lack the casparian strips to allow passive transport of solutes into vascular cylinder
-not always present
112
plant mutualistic relationships
-more than 75% of plant species have fungal associations with their roots
-mycorrhizae (fungus) facilitate absorption of water and nutrients (particularly phosphorus)
-plants provide protection, sugars, and amino acids to fungus
-two types: ectomycorrhizae and endomycorrhizae
113
ectomycorrhizae
-fungi remain on surface
-form a mantle around the root
-plants benefit from increased absorption of minerals
-fungi have a solid substrate to grow on
114
endomycorrhizae
-fungi penetrate root cortex (parenchyma cells)
-fungi form branching structures called arbuscules
-plant increases absorption of nutrients
-fungi provided with food and protection
115
bacteria root nodules
-some species of bacteria (rhizobia) associate with legumes
-bacteria have enzymes that can convert nitrogen from the atmosphere into usable plant forms
-root nodules contain large numbers of nitrogen fixing bacteria
116
primary root growth
-apical meristem in center of root tip
-divided into three meristematic areas:
1. protoderm (gives rise to epidermis)
2. ground meristem (gives rise to cortex)
3. Procambium (gives rise to primary xylem, phloem, and pericycle)
117
regions in primary root growth
1. region of maturation
-cells mature (differentiate) into distinctive cell types
2. region of elongation
-cells become several times original length
-not differentiated
118
what is the pericycle
-single cell layer
-located directly below the epidermis
-gives rise to lateral root and part of the vascular cambium
119
lateral roots growing from the pericycle
-pericycle displaces cortex and epidermis as lateral root grows outwards from the vascular cylinder to the epidermis
-lateral root eventually break through epidermis
-vascular cylinder of lateral roots stays connected to that parent root
120
secondary growth in roots
-no secondary growth in fibrous monocot systems
-secondary growth occurs where primary growth has been completed
121
why do dicots and conifers have secondary root growth
1. increase conductivity
2. replace old vascular tissue
3. provide protection
4. form specialized storage roots by anomalous secondary growth (thickening)
5. provide support in specialized roots
122
vascular cambium and secondary root growth
-vascular ccambium form de-differentiated parenchyma between primary xylem and phloem and pericycle
-initiated by the hormone auxin
-vascular cambium forms continuous ring of meristemic cells
-as in stems, secondary xylem is wood and less secondary phloem is produced
123
cork cambium in secondary root growth
-cork cambium forms dedifferentiated parenchyma cortex, then secondary phloem
124
anomalous secondary thickening for food storage
-storage cells of root vegetables are a combination of root and stem
-store simple carbohydrates
-expands by anomalous secondary thickening of xylem, phloem, and parenchyma
125
root periderm scars
-many food storage tap roots have root periderm scars that resemble lenticles but they are not for gas exchange
-when lateral root breaks through periderm, wound response creates scaring
126
root specialization for asexual reproduction
-roots form adventitous buds
-aerial stems (suckers) form
-suckers develop their own roots and can survive independently
127
root specialization for gas exchange
plants growing near water or swamps can have pneumatophores that extend above the surface and use lenticles to obtain oxygen
128
root specialization; aerial roots
-epiphytes such as orchids grow on other plants for support but nourish themselves (not parasites)
-velamen layer is epidermis several layers thick to reduce water loss
-epiphyte roots absorb water and nutrients from rain water
-aerial roots can also aid in climbing
129
root specialization; aerial (prop) roots
-tropical trees have stilt like prop roots that grow down from branches
-once they reach the ground they continue secondary growth to expand radius and stability
130
root specialization; additional support
-buttress roots extend from the base of the tree trunk to help stabilize tree in shallow soil
-common in tropical trees
131
root specialization; parasitism
-parasitic roots (dodders) have no chlorophyll and dependant on chlorophyll-bearing plants for nutrition
-dodders use peg like projections (haustoria) to tap into the vascular system of host plant
132
what is apoplastic transport
-dead space
-space outside of plasma membrane
-through permeable cellulose cell wall and middle lamellae
133
what is symplastic transport
-living space
-cytoplasmic continuum between cells
-does not cross plasma membrane
-through cytoplasm and plasmodesmata
134
what is transmembrane transport
-living space
-movement through semi-permeable plasma membranes
-through cytoplasm, plasma membrane, and cell wall
135
symplastic transport; plasmodesmata
-tiny stands of cytoplasm that connect cells (symplast)
-water and dissolved substances can pass through the plasmodesmata
-only certain size of molecules can pass between cells, size exclusion limits
-do not have to pass through semi-permeable plasma membrane
136
root transport pathways
1. apoplastic
-movement through permeable cell walls
2. transmembrane
-must pass size exclusion limit
3. symplastic
-must pass through semi-permeable barrier
137
casparian strip and transport
-block apoplastic pathway
-only symplastic and transmembrane
-plasmodesmata on front and back of endodermal cells facilitate transport into pericycle
-water and solutes enter xylem from pericycle via apoplastic
138
transport in the vascular cylinder
-sap is the fluid transported in xylem (tracheids and vessel members) or phloem (sieve tube elements)
-sap is made up of water, nutrients, and sugars
-maple syrup is sap moving up from storage roots in the spring
139
structure of tracheids
-narrow and tapered
-staggered stacking
-closed off at tapered ends
-dead at maturity
-thick lignified secondary walls
-provide structural support
-pits on side of vessels allow lateral water and solute flow
140
structure of vessel members
-wide
-short units but when stacked together can be meters long
-transport 100x more water than tracheids
-stacked on top of one another to form pipes
-perforation plates or open ended at top and bottom
-continuous water flow
-dead at maturity
-thick lignified secondary walls
-provide structural support
-pits on side of vessels allow lateral water and solute flow
141
pits in tracheids
1. simple pits
-pore formed from absence of secondary wall
-primary wall is the only barrier
2. bordered pits
-have secondary wall extending over opening and a torus that functions like a hydraulic valve
142
what is a torus
-helps block movement of gases and pathogenic microorganisms
143
what is adhesion
-the attraction between different kinds of molecules
-most important
-water molecules adhere to cellulose walls of xylem tracheids and vessels, forming water column
144
what is cohesion
-the attraction between molecules of the same kind
-water molecules are polar and bind to each other which further supports the water column
145
what is tension
-negative pressure on water or solutions
-negative pressure draws water upward
-tension is created by transpiration (evaporation of water)
146
what is cavitation
-tracheids and vessel members have thick lignified secondary walls to withstand tension from negative pressure
-greater tension increases the risk of breakage of the water column
-trunks of trees can contract from tension like a straw
-formation of air bubbles or ice crystals can break the water column (embolisms)
-breakage occurs less in tracheids than vessel members because of anatomical differences
147
embolisms in tracheids vs vessel members
-water is less supported by vessel member walls because they are wider, making the formation of air bubbles more likely
-embolisms form separately in each tracheid and have to move through pits
-in vessel members, entire column fills with air or ice when cavitation occurs
148
what is water movement controlled by
1. bulk flow
2. diffusion
3. osmosis
149
bulk flow
-molecules of water move in mass from one place to another in response to differences in potential energy
150
diffusion
-the spontaneous movement of water down a concentration gradient
151
osmosis
-movement of water across a selectively permeable membrane
-water movement across plasma membrane is facilitated by aquaporins
-water flows spontaneously from a region of lower solute concentration to a region of higher solute concentration
152
hypotonic solution
-the solution surrounding the cells has a lower concentration of solutes
-water moves into cell, cell wall prevents cell rupture
-ideal condition
153
isotonic solutions
-the solution surrounding the cells has the same concentration of solutes
-water is at equilibrium but the cell is not turgid
154
hypertonic solutions
-the solution surrounding the cells has a higher concentration of solutes
-water flows out of the cells and the plasma membrane shrinks away from the wall (plasmolysis)
-symplastic transport is impaired
-unusual to see in nature
155
what is water potential
-measurement that predicts which way water will flow between a plant cell and its surroundings
-is negative when hypotonic
-is 0 when idotonic
-is positive when hypertonic
156
relative water potential
-relative values are more important in determining direction of flow than absolute values
-water potential becomes more and more negative as water moves up from the soil to the leaves
-tension is created by water evaporation from leaves causing a pull on the water column
157
what is transpiration and its purpose
-release of water vapour into the air from aerial regions
-two functions:
1. cools leaves heated by sunlight
2. pulls water and water soluble minerals up from the roots
158
what are stomata
-90% of transpiration occurs through the stomata
-occur at highest density on underside of leaves
-occupy more than 1% of leave surface area
-can be found on all aerial organs
159
how do stomata regulate transpiration
-opening and closing of stomata is controlled by turgor pressure of guard cells
-turgid guard cells: open
-flaccid guard cells: close
160
transpiration in lenticles
-pores than cannot regulate to open and close
-only account for 0.1% of transpiration
-in some fruits, lenticles form from stomata and these can account for 20% of transpiration in a plant
161
transpiration in cuticle
-allows very little water loss (about 5%)
-plants in dry environment will try to reduce water loss by:
1. thicker cuticle
2. mesophyll packed close together, no air spaces
3. sunken stomates to reduce evaporation
4. increased layers in epidermis
5. only open stomata at night
