Tree Biology Flashcards
Angiosperm
A flowering plant or tree
Gymnosperms
Group of seed producing plants and trees
Meristem
Specialized growth initiation areas were new cells arise from the division of existing cells
Differentiation
A process which changes a cells structure that allows it to assume a variety of specific functions
Primary growth
Growth from the root and shoot tips resulting in an increase of height and length
Secondary growth
Growth that increases the thickness of stems and branches
Apical meristem
The area of primary growth at the tips of roots and shoots
Bud
Newly developing shoot
Cambium
A vascular lateral meristem. A thin sheath of dividing cells located just under the bark which produces cells that will become the vascular system of the tree
Xylem
Tissue which transports water and nutrients from the roots to the stems and leaves. Also stores carbohydrate (starch) reserves and defends against disease dysfunction and decay.
Phloem
Vascular tissue that transports photosynthates, sugars and other metabolic products down the tree from the leaves
Cork cambium
The second lateral meristem that produces the outer tissues and the bark
Cellulose
The primary structural component in cell walls
Lignin
A rigid component of cell walls that form microfibrils ( long chains of cellulose) creating the structural integrity of the cell walls
Tracheid cells
Elongated closed ended dead cells with pointed tips and thickened walls, that conduct water and provide mechanical support
Parenchyma cells
Living cells interspersed among other cells that store carbohydrates and defend against decay
Vessels
The primary conducting elements in angiosperms (eudicotyledon)
Ring porous
The formation of wide vessels early in the growing season and narrower vessels later in the season
Diffuse porous
Uniform vessel size production through out the growing season
Growth rings
The result of the cambiums seasonal xylem production
Early wood
Cells produced early in the growing season
Late wood
Cells produced later in the growing season
Sapwood
Xylem that conducts water
Heartwood
Non water conducting xylem that contains no living cells and is often darker in color
Rays
Made up of parenchyma calls that grow radially across the xylem and into the phloem. Transports and stores carbohydrates and protects against decay
Lenticels
Small openings in the bark that allow gas exchange of oxygen and carbon dioxide
Apical bud/Terminal bud
Buds located at the end of the shoot
Axillary buds / Lateral buds
Located along the stem
Apical dominance
Occurs when the apical bud chemically inhibits the growth and development of axillary buds on the same shoot
Adventitious buds
Buds that are produced along stems or roots where meristems are not normally found
Epicormic shoots or sprouts
Latent buds or adventitious buds that produce elongated shoots
Node
Slightly elongated portion of the stem where leaves and buds develop
Internode
The area between nodes
Branch collar
The annual production of layers of tissue that form around the branch and the stem
Branch union
The junction of specialized wood where the branch meets the stem
Branch bark ridge
An external sign where specialized wood growth is occurring between the branch and the stem
Included bark
Occurs when bark grows between the branch and stem in the branch bark ridge and prevents the development of the specialized wood for structural support
Chloroplasts
Specialized cells that contain chlorophyll used in photosynthesis
Chlorophyll
The pigment in chloroplasts that absorbs sunlight for photosynthesis
Photosynthesis
The process in which sunlight is used to synthesize carbon dioxide and water into carbohydrates
Transpiration
The controlled loss of water from stomata in the leaves to facilitate water uptake through the xylem
Cuticle
The waxy covering on leaves to prevent the desiccation of the leaf
Stomata
Small openings on the under sides of leaves to control water loss and gas exchange
Guard cells
Regulate the opening and closing of the stomata in response to environmental stimulus by cellular turgor
Deciduous
Trees that seasonally lose their leaves
Evergreen
Trees that hold their needles or leaves for more then one year
Abscission zone
The area at the base of the leaf stalk, or petiole,in the autumn; serves two functions, enable leaf drop and to protect that area from pathogen entry or desiccation.
Anthocyanins
Red and purple pigment that is produced during fall
Carotenoids
Yellow orange and red pigments produced during fall. This pigment protects leaf cells from UV radiation
Absorbing roots
Small fibrous roots that are the primary tissues growing along and from the ends of larger woody roots. Usually found in the upper 30 cm of soil.
Lateral roots
Horizontal roots that usually grow near the surface soil
Sinker roots
Grow vertically downward off the lateral roots. Provides better anchorage and access to water deeper in the soil
Tap root
The initial root grown off a seedling that grows straight down. Offer replaced or diverted from its downward growth later in life
Root crown
The area where roots meet the main trunk of the tree (aka trunk flare)
Zone of rapid taper
The zone where the roots taper down dramatically into longer thinner roots
Respiration
A process independent of light where carbohydrates are converted in a controlled manner into energy
Transpiration
Is the loss of water vapor through the stomata in the leaves
Cell turgor
Pressure built up by water inside cells, can be controlled by the cell
Osmosis
The movement of water through a membrane from a high water potential area to a low water potential area
Source
An area of part of a tree where carbohydrates are produced or stored
Sink
An area where carbohydrates are consumed or where carbohydrates are consumed more than are being produced
Axial transport
The transport or water or nutrients vertically through the xylem or phloem
Radial transport
Movement of water or nutrients within the tree through cells of different ages typically done through ray cells
Ray cells
Living channels of cells that run horizontally through the tree that transport water and nutrients
Plant growth regulators
Chemical messengers that regulate growth and development
What are the major hormones in plant growth regulation
Auxins, cytokinins, gibberelins, ethylene, abscisic acid
Auxins
A plant growth regulator mainly found in shoot and root tips. Important for root development
Cytokinins
Produced in the roots and are instrumental in root and shoot initiation and growth
Tropism
The directional growth of a plant or tree in response to environmental stimulus
Decurrent growth
Where lateral shoots out grow the vertical shoots and the tree develops a more rounded canopy
Excurrent growth
Growth where the vertical shoots out grow the lateral shoots, and form a central leader. Ex conifers
CODIT
Compartmentalization of decay in trees
Compartmentalization
The process where trees can limit or stop dysfunction or decay
In Shigos model of codit what are the four walls?
Wall 1: resist the longitudinal spread of decay by plugging xylem vessels and/or trachied pits
Wall 2: resist inward decay by developing late wood cells and depositing special chemicals into these cells
Wall 3: inhibits lateral spread of decay by activating ray cells to resist decay.
Wall 4: new wood tissue that grows around the decay to prevent the outward spread of decay
Which three walla form the reaction zone
Walls 123
Which wall or walls are the barrier zone
Wall 4 new wood tissue
Shakes
Lengthwise separation of wood along the grain usually occurring between growth rings
Name the layers of a tree from the outside in
Epidermis, cork cells, cork cambium, phelloderm, cortex, phloem, cambium, xylem
