Marine Botany Exam 3

Halophytes

What are plants that have adaptations to prevent water loss and grow in saline habitats called?

Mangrove (mangrove wetland)

What are the coastal ecosystems dominated by halophytic trees and shrubs called?

Lenticels

What are the loose aggregations of cells that allow for gas exchange in woody plants?

Coral reefs

What kind of structures composed of shells and skeletons of hermatypic organisms are known as?

What is the narrow region of soil directly influenced by root secretions and associated microorganisms?

Rhizosphere

What is the main limiting factor for mangrove geographic distribution?

Temperature

List the 6 classifications of mangrove wetlands.

Coastal fringe, overwash islands, riverine, basin, hammock, dwarf/scrub.

What is the difference between prop roots, drop roots, and pneumatophores?

Prop roots are from the stem; drop roots are from branches; pneumatophores are vertical extensions of horizontal roots.

In addition to aerial roots, what three types of roots do mangroves produce?

Absorbing, anchoring, cable roots.

What adaptations have mangrove leaves developed to survive in marine environments?

Single layer epidermis, thick outer walls and cuticle, specialized epidermal cells, and hypodermis contains hydrocytes.

Salt marshes are found where the accumulation of sediments is equal to or greater than what other factor?

Land subsidence.

How do abiotic stressors differ between low and high marsh zones in salt marshes?

Low marsh has more inundation; high marsh has higher salt content in soil.

List four examples of salt content regulation in marsh plants.

Ion exclusion in roots, growth & succulence, shedding, secretion (salt glands), root discharge, controlling water loss.

What are the three types of xeric leaves found in salt marsh plants?

Succulent, thick, dry type.

What are three commonly occurring salt marsh genera in NC marshes?

Salicornia, Sporobolus, Juncus,

What five characteristics define seagrass?

Grow fully submerged, saline environment, hydrophilous pollination, roots, compete successfully in marine environments.

What percentage of angiosperms live in the marine environment?

0.01%.

Why are seagrass meristematic tissues especially vulnerable to low oxygen?

Located at transition between water column and sediment, high metabolic activity, high oxygen requirement for mitotic growth.

How many years ago did angiosperms return to the sea during seagrass evolution?

100 million years ago.

Name three seagrass species found in NC.

Zostera marina, Halodule wrightii, Ruppia maritima.

Which two groups of organisms are primarily responsible for biogenic reef building?

Cnidarian corals and calcified red algae.

What four characteristics do coral reefs develop in?

Oligotrophic water,

high-water transparency,

high-water movement,

stable water temperature.

What are the four primary biological processes responsible for nutrient uptake in coral reefs?

Biofiltration by epiphytic microflora, filter-feeding reef fauna, mutualistic relationships, tight nutrient cycling.

Why do corals dominate reefs in tropical environments and algae in temperate environments?

Nutrients and competition.

How do coral polyps acquire zooxanthellae?

Mobile stage is absorbed in digestive tract,

protected by periplast,

and absorbed into tissues.

Succulent.

What adaptation allows plants with fleshy tissues to conserve moisture?

Hydrophilous.

What type of pollination is mediated by water and is abiotic?

Vivipary.

What is the term for the germination of seedlings while the fruit remains attached to the tree?

Salt marsh.

Describe a halophytic grassland on alluvial sediments bordering saline water bodies where water level fluctuates either tidally or nontidally.

What is the form of clonal growth where perennating buds are situated at or just below the soil surface?

Hemicryptophyte.

Mangrove flowers are perfect, meaning they have what flowering organs?

Sepals, petals, stamens, carpels.

Name 3 mangrove species found in the US.

Rhizophora (red), Avicennia (black), Laguncularia (white).

What are the 4 adaptive characteristics mangroves have developed to survive in coastal systems?

1. Attach to soft sediment

2. Aerial roots

3. Vivipary, seeds/seedlings survive/disperse in saltwater

4. Xerophytic and halophytic modifications.

What are the general canopy characteristics of mangrove forests?

Evergreen, ovate to elliptical leaves, flexible but firm leathery leaves, salt-excreting glands.

What three factors limit mangrove seed dispersal?

Salt water, water movement, stressful intertidal environment.

How does high tide impact salt marsh plants?

Edaphic changes (lower soil aeration and redox potential),

lower photosynthesis, damage or uprooting of plants due to water movement,

anaerobic sediments.

List five major ecological roles of coastal plant communities (including salt marshes).

Primary production, food source, habitat, sediment stabilization, water filtration.

What are three xerophytic adaptations to maximize water retention in stems, leaves, and roots?

Increased lignification, complex epidermal development, well-developed bundle sheaths.

Salt marsh ecosystems are balanced between biota and what two other major types of drivers?

Hydrology and physiochemical environment.

What are three ecophysiological impacts of salinity stress on salt marsh plants?

Dehydration,

increased cellular ionic strength,

loss of turgor pressure,

photosynthetic & metabolic shutdown,

curling,

wilting,

mortality.

In a transient seed bank, seeds remain viable for less than how long?

Less than one year, while in a persistent seed bank seeds are viable for more than one year.

What are the three main morphological categories of seagrass plants?

1. Pair of petiolate leaves or two or more leaflets

2. Shoots with a distinct erect stem and strap-shaped leaves

3. Plants without visible erect stems, but with strap-shaped leaves.

Patterns of reproduction will vary with what three biotic factors?

Genetics,

physiology,

conditions of the local populations.

Why are seagrasses called seagrasses?

Herbaceous growth and formation of extensive meadows.

What are the five adaptations seagrasses have developed to survive in the marine environment?

Hydrophilic pollen,

flexible tissues,

hydrodynamic

design,

no cuticle

, lacunar system.

What is a direct or indirect human impact on marine plants caused by increased ultraviolet irradiance?

Indirect.

What is a direct human impact on marine plants due to excavation activities?

Dredging.

Halophytes have what type of growth rates, nutrient uptake rates, and photosynthesis compared to non-halophytic plants?

Lower growth rates,

lower nutrient uptake rates,

and reduced photosynthesis.

What are three advantages of asexual reproduction?

Maintains 'good' genotypes;

removes need for opposite sex;

escape in numbers;

removes real cost of reproduction.

What is a direct impact of eutrophication on marine plants?

Direct.

How do seagrasses and algae differ?

Seagrasses have a complex root structure to anchor the plant in the sediment,

extract nutrients and minerals,

photosynthesis in leaves

, a vascular system,

reproduce via flowers & seeds.

What are some of the sustainable development goals for seagrass

1. No poverty

2. Life below water and land

3. Reduce inequalities

4. Climate action

What are the 3 main morphological categories for seagrasses

1. Plants with erect stems and terminal strap shaped leaves

2. Plants with strap shaped leaves arising directly from rhixome’s

3. Plats with petiolate or compound leaves (not strap shaped)

seed bank

viable seeds in sediment

rhizosphere

narrow region of soil that is directly influenced by root secretions and associated soilmicroorganisms

What are wat to regulate shoot salt content

1. Shedding

2. Root discharge

3. Controlling water loss

What are the primary mechanisms of marine calcification

1. Geochemical precipitation: CaCO3 forms as photosynthesis reduces CO2

2. Biomineralization: Protozoans and animals build shells when CO2 levels are low enough for energetically efficient calcification

3. Photosynthetic coupling: Some organisms use calcification to release CO2 and support photosynthesis

What are th eprimary biological processes responsible for nutrients uptake in coral reef

1. Biofiltration by epiphytic microbes

2. Filter-feeding fauna such as sponges coral polychaetas and bivalves

3. Mutualistic symbiosis that recycles inorganic and organic nutrients

4. Tight nutrint cycling within semi enclosed reef systenm

How is erosion for coral reefs

1. Most biogenic production is eroded

2. Eroded sediment wash inot back reef or down outer slop

What is erosion due to

1. Boring by animal’s plant fungi

2. Mechanical weathering by waves

Shlerophylly

The normal development of much sclerenchyma in the leaves of plants resulting in thickened hardened foliage that resist loss of moisture

Lenticles

A loose aggregation of cells which penetrates the surface of a woody plant and through which gases are exchanged between the atmosphere and the underlying tissues

What are the types of aerial roots

1. Prop Roots

2. Drop roots

3. Pneumatophores

4. Roots knees

5. Plank roots

What are the characteristics od a mangrove

1. Trees show mechanic adaptation for attachment in soft or lose substrata

2. Aerial roots are common ans show specilization for diffusion of gases to subterraneasn portions

3. Evolved vivipary

4. Seeds and seedings can survive in salt water and utilize seawater as a mean of dispersal

5. Trees exhibit xerophytic and halophytic modifications

Mangrove wetland

subtropical and tropical coastal ecosystems dominated by halophytic trees shrubs and other plants growing in brackish to saline water