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Questions and Answers
What is the primary function of the vascular cambium in trees?
What is the primary function of the vascular cambium in trees?
All cells in a tree are identical and perform the same functions.
All cells in a tree are identical and perform the same functions.
False
What are the two types of meristem responsible for tree growth?
What are the two types of meristem responsible for tree growth?
Apical meristem and lateral meristem
The ____ cambium produces bark in trees.
The ____ cambium produces bark in trees.
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Match the tree structure with its primary function:
Match the tree structure with its primary function:
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What characterizes softwood?
What characterizes softwood?
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Heartwood is the living part of the xylem and actively conducts water.
Heartwood is the living part of the xylem and actively conducts water.
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What is the primary function of sapwood?
What is the primary function of sapwood?
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Wood classified as _____ contains both tracheids and vessels.
Wood classified as _____ contains both tracheids and vessels.
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Match the following wood types with their characteristics:
Match the following wood types with their characteristics:
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Study Notes
Tree Biology Overview
- Understanding tree growth is essential for growing trees.
- Trees have several parts, including roots, a trunk, branches, buds, leaves, and bark.
- Each part plays a specific role in the tree's life cycle.
- Roots anchor the tree, absorb water and nutrients from the soil, and store water and energy-rich compounds.
- Trunk transmits water and nutrients to other parts of the tree.
- Branches and buds help support leaves and facilitate the growth of new branches and leaves.
- Leaves carry out photosynthesis to produce sugar, and transpiration to regulate water.
- Bark protects the tree from the environment.
Tree Anatomy
- Parts of the tree include the pith, cambium, sapwood, heartwood, xylem, phloem, bark, and vascular rays.
- Xylem is a woody tissue that transports water and dissolved nutrients from the roots upwards.
- Phloem transports sugars made by photosynthesis from leaves to other parts of the tree.
- Sapwood is the lighter-colored outer layer of the xylem that is involved in water transport.
- Heartwood is the darker-colored inner layer of the xylem, and it is no longer involved in water transport.
Anatomy of a Plant Cell
- Plant cells have cell walls, cell membranes, nuclei, mitochondria, chloroplasts.
- Cell walls are composed of cellulose.
- Mitochondria are responsible for respiration.
- Chloroplasts are involved in photosynthesis.
Tree Growth
- Growth is a complex process that involves cell division, differentiation, and specialized cells.
Meristem Types
- Apical meristems are located at the tips of stems and roots, responsible for primary growth.
- Lateral meristems include vascular cambium (produces xylem and phloem) and cork cambium (produces bark).
Factors Affecting Tree Growth
- Genetics (DNA)
- Physiological processes
- Environment, including:
- Moisture
- Air
- Nutrients
- Temperature
- Light
Tree Ratios
- 5% leaves
- 15% stems
- 60% trunk
- 15% woody roots
- 5% absorbing roots
Functions of Sapwood
- Transport of water from roots to shoots
- Energy storage
- Providing mechanical support to the tree
- Resisting decay from production of chemicals
Wood Types
- Softwoods: comprised solely of tracheids (e.g., pine, other conifers).
- Hardwood: comprised of tracheids and vessels (e.g., oak, maple).
- Ring porous hardwood: characterized by large vessels during spring growth and smaller vessels during summer growth.
- Diffuse porous hardwood: display vessels roughly the same size over all seasons.
Tree Structures
- Trunks, stems, and branches support the tree, store carbohydrates, and transport water and nutrients.
- Stem Structure in a young stem has: cuticle, epidermis, cork cells, cork cambium, phelloderm, cortex, phloem, cambium, xylem.
Plant Hormones
- Auxin: essential for root initiation, cell division, and apical dominance.
- Cytokinin: promotes cell division.
- Gibberellin: stimulates cell elongation.
- Abscisic Acid: aids leaf abscission and inhibits growth.
- Ethylene: hastens fruit ripening.
Tropisms
- Tropisms are directional growth responses of plants in response to external stimuli.
- Geotropism: plant growth response to gravity (e.g. roots grow down, shoots grow up)
- Phototropism: plant growth response to light (e.g. plant bending towards light sources).
Respiration
- Respiration is the process where sugars are broken down in the presence of oxygen, releasing carbon dioxide, water, and energy.
- Trees need oxygen for respiration.
Transpiration
- Transpiration is the loss of water through leaves in the form of water vapor.
Osmosis
- Osmosis is the movement of water molecules across a membrane from an area of high water concentration to low water concentration.
Transport
- Axial transport: movement of water, nutrients, sugars, and other solutes up and down the tree.
- Radial transport: movement of sugars across the xylem and phloem through rays.
Source/Sink
- Source: Plant structures that produce energy (e.g., leaves).
- Sink: Plant structures that consume energy (e.g., roots, fruits).
Epicormic Shoots
- Suckers: shoots emerging below the graft union or from the root system.
- Watersprouts: shoots emerging above the graft union from dormant buds
Leaf Structure
- Leaves have epidermis on the top and bottom.
- The top portion hosts palisade cells and the lower portion has spongy mesophyll.
Fall Color
- Cool days (not freezing)
- Shorter days
- Bright sunny days
- Factors combine to affect chlorophyll production and allows other pigments to be visible.
Roots
- Anchor and support the tree
- Absorb water, nutrients
- Store water, energy-rich compounds
- Transport compounds to the trunk
- Produce organic compounds.
Root Types
- Absorbing roots (fine non-woody roots responsible for water and nutrient absorption)
- Lateral roots (woody horizontal roots)
- Sinker roots (woody vertical roots)
Root Crown
- Location where the roots and trunk connect
Root Tip Anatomy
- Maturation zone (where cells different into various tissues)
- Elongation zone (where newly formed cells grow larger in size)
- Meristematic zone (site of active cell divisions)
- Root cap (protects the root as it grows through the soil)
Root Systems
- True Taproots
- Heartroots
- Plateroots
Mycorrhizae
- Symbiotic relationship: mutual benefits (fungus and plant roots)
- Absorption of water, nutrients
- Barrier against pathogenic fungi
- Secret substances that inhibit pathogenic fungi
- Ectomycorrhizae and Endomycorrhizae (types)
Products From Photosynthesis
- This process occurs in leaves, producing sugars, starch, lipids, protein, cellulose, and allelochemicals.
Palm Crown and Fronds
- One bud for new leaf production
- If the bud dies or gets cut, the tree will also die;
- Fronds may grow slowly.
Palm Trunk
- Palm trees don't compartmentalize decay
- Size of the trunk doesn't routinely increase;
- Environmental stress can cause trunk damage
Palm Roots
- Cabbage palm roots regenerate near the root initiation zone.
- Coconut palms regenerate from the root tip or rizome.
- Queen and Royal palms regenerate new root tips.
Codes to study
- CODIT (Compartmentalization of Decay In Trees).
- Walls 1-4 resisting decay in tree structures.
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Description
Explore the essential parts and functions of trees in this quiz on tree biology. Understand how each component, from roots to bark, contributes to tree growth and survival. Delve into tree anatomy and the roles of xylem and phloem in nutrient transport.
