Plants Flashcards
Sonoran Desert (Location)
An ecosystem located in Southwest USA and Northwest Mexico
When is the growing season in the Sonoran Desert and why?
It has a real issue of running out of water in the summer (only 1.5 inches of rain) so the only good growing season for plants is during winter
What are annual plants?
A plant that completes it life cycle in one year then die (shorter-lived, faster growing)
What are perennial plants?
A plant that regrows in a specific season, grow back every year (slower growing, longer life)
How is climate changing?
Temperature increases, rainfall is more episodic and the amount of rain decreases (althought it can be more intense), more flooding and droughts
Why is water important for plants?
For structural purposes; on a cell level, it causes osmosis and turgor pressure
What part of the plant absorbs water?
Roots
What part of the plan has the sugar or sunlight?
Leaf
What percentage of plants make up the Earth’s biomass?
80%
What molecule makes up most of a plant’s biomass?
Cellulose
Where does the carbon in cellulose in a plant come from?
From the air (CO2)
Photosynthesis
6CO2 + 6H2O (l) + sunlight –> glucose + 6O2 (g)
Equilibrium Concentration
Movement from high to low concentration in order to create balance
Passive Transport
ATP is not needed, potential energy in the form of a gradient is transformed to kinetic energy
Diffusion
Net movement of molecules from areas of high concentration to low concentration
Osmolarity
Movement of solvent (water) across a semipermeable membrane from high to low concentration (created equilibrium of solute and solvent)
Osmosis
Diffusion of water, water concentration and solute concentration are opposites
Dilute: high H20, low solute
Concentrate: low H20, high solute
Turgid Cell
water enters through osmosis, vacuole swells and pushed against cell wall
Flaccid Cell
water is lost, vacuole shrinks, cell loses shape
How does water enter from the roots (bottom) and leave from the stomata (top)?
Due to the transport system in plants
What are a plant’s vascular tissue?
Xylem and Phloem
Xylem
Only moves water in one direction from the roots to the leaves (water up)
Phloem
Carries nutrients, sugar, hormones, etc. around through osmosis (glucose down)
Turgor Pressure
Created when water flows into the vacuole of a plant cell and then pushes outward on the cell wall, allows the plant to stand straight and grow
How does the xylem move water?
passive transport, capillary action
Stomata
gaps in the leaf/ that open and close for gas exchange using guard cells
Why is biodiversity important in the Somoran Desert?
All organisms want to maximize fitness
Gas Exchange
stomata will open when guard cells are turgid with an abundance of water and closed when water is scarce and the guard cells are flaccid, the exchange of O2 and CO2 that causes water loss
What would happen if the stomata never opened?
no photosynthesis, O2 toxicity and no growth/death of plant
How will a plant wilt faster?
drier air (humidity), high temperatures, windy, surface area (more exposure and more stomata)
Transpiration
evaporation of water from plants
What does the total amount of water transpired depend on?
Depends on the amount of time stomata are open and the rate of water loss
How can winter annuals survive without a lot of water?
1) when it does rain, the plant can grow quickly and hope they don’t dry out (quick growth)
2) limit water waster and conserve, have a slow life cycle
Risks of Fast Growth
Could die without reproduction
Risks of Slow Growth
Could be out competed by faster growing plants
Relative Growth Rate (RGR)
biomass gained over time
Water Use Efficiency (WUE)
carbon gained (growth) over water loss
Why can you not be high in RGR and WUE?
high RGR means a lot of leaves for photosynthesis but with more stomata on the leaves and more surface area, there is more water loss
What are the issues with the amount of winter precipitation and plants?
the amount of precipitation is not consistent which means there is more of a chance of smaller rain events (which is better for slower growers) meaning that there are different plants growing different years