Extreme environments and light

POPS UCF Dr. Tye

What is the holarctic floristic kingdom

Most of North America and temperate Laurasia

What is the South American floristic kingdom

South Florida to Patagonia

What is African floristic kingdom

All of Africa except the mediterranean area

What is the indo-pacific floristic kingdom

India to Pacific islands

What is the Australian floristic kingdom

Australia and some surrounding islands

What is the tundra biome made of

Small-sized plants adapted to short seasons

What is the taiga biome made of

Conifer forests

What is the deciduous forests biome made of

Broad-leaf temperate forests

What is the grassland biome made of

Prairies, steppes, savannah, pampas

What is the scrubland biome made of

Chaparral, shrub, etc

What is the desert biome made of

Plants are further apart than in scrublands

What is the tropical forests biome made of

Humid and warm- peak diversity

What are environmental factors

An organisms reaction to individual external influences

What are biotic factors

Result from interactions with other organisms (herbivory, infection, symbiosis, competition, etc)

What are abiotic factors

Parameters (temperature, pH, humidity) and resources (light, water, minerals) that determine growth and factors that can add stress (pollution)

What are limiting factors

An environmental factor at suboptimal level that can limit plant processes (CO2 limit photosynthetic rate)

What is stress

Occurs when essential factors (light, water, oxygen, nutrients) are at inappropriate levels

What are environmental nova

Factors that trigger stress at ANY concentration (heavy metals, pollutants)

What is latent life

Minimal life processes occur

What is dormancy

An adapted latent life stage. Triggered by environmental cues. Involves physiological changes

What is avoidance strategy

Seeds and spores allow annual/ephemeral plants to avoid moments of highest environmental stress

What are mesophiles

Plants that require moderate temperature to grow

What is hardening

Process by which tolerable stress levels trigger the plant to prepare for extreme conditions

How is the surface and adaptation to high temperature

Hairs can reduce evaporation and reflect intense sunlight

How is size an adaptation to high temperature

Smaller, thicker leaves help minimize effect of high light intensity

How is angle/position an adaptation to high temperature

Some species can move leaves to reduce exposure to sunlight

How is transpiration an adaptation to high temperature

Increased transpiration can help maintain the plant cooler than surrounding environment

How is shading an adaptation to high temperature

Plants use some structures to protect others from direct sunlight

How is avoidance strategy an adaptation to high temperature

In hot environments, many species are short-lived annuals and avoid worst conditions

How are rosette/low growing plants an adaptation to cold temperature

Protected against weight of snow and environment/warmer closer to ground

How are evergreen plants an adaptation to cold temperature

Have high concentrations of sugar in leaves that act as anti-freeze

How are deciduous plants an adaptation to cold temperature

Leaf abscission and bud splashes to protect axillary meristems

What are the products and reactants of photosynthesis

R= carbon dioxide and water

P= Sugar and oxygen

What captures sunlight

Chlorophyll located in thylakoid membranes in chloroplasts

What produces the vast majority of energy on Earth

Sunlight, its intensity and composition vary with location, time of day, and season

What happens if light is too low

Negative energy balance- not enough photosynthesis to cover plant’s metabolic requirements

What happens if light is too high

Unused energy can lead to oxidative stress

What is the pulvini

Joint like thickening at base of leaves that allows for movement of leaves

What plants can move their chloroplasts to different parts of cell to increase or reduce exposure to light

Ferns, mosses, and some seed plants

What are sun leaves

Smaller and thicker, with well-developed mesophyll and several layers of palisade cells-epidermal hairs might minimize excess sunlight

What are shade leaves

Larger and more tender with weakly developed mesophyll- epidermal cells might act as lenses to increase light capture

What are sun leaves at a sub cellular level

Have chloroplast with small grana and few stroll thylakoid

Photosystem- small proportion of antenna and many reaction centers

What are shade leaves at a sub cellular level

Chloroplast with large grana and many stromal thylakoids

Photosystem- large proportion of antenna and few reaction centers

What are stolons

Aboveground stems; emerge from crown and bend downwards; develop planters where they touch the ground

What are stoloniferous rhizomes

Belowground stems; upright shoots develop from axillary buds in nodes; adventitious roots in underside

What are suckers

Upright shoots growing from horizontal roots

What are twiners

“barber pole” stems of vines that grow in spirals around objects such as small trunks

Supports itself

What are tendrils

“hug” modified leaf or short stem that wraps around objects they touch

What are adhesive pads

At tips of tendril-like short stems

Allow plants to attach to walls

What are buttress roots

Wedge-shaped, tall and wide- they prevent shallow-rooted trees from falling over

What are prop roots

Adventitious/aerial roots that arise from the trunk and grow downwards to provide support in shifty conditions

What are epiphytes

Grow in wet areas. Use their roots to grasp tree branches L

What are lianas

Typically in rainforests; woody, creeping vines that spread through the canopy spreading their leaves to the sun