plant stress Flashcards
(67 cards)
what is plant stress
prevents plants from growing to their full potential
how do plants respond to stress
plant stress responses describe characteristics observed when plants detect stress, not all plants respond to stress in the same way.
understanding the plant’s stress is an important and challenging topic
what is abiotic stress caused by
It caused by non-living factors
what are some examples of abiotic stress
nutrient stress, salt stress, cold stress, heat stress
how does salt cause plant stress
salts in soil deprive plants of water and dissolved nutrients.
plant roots have a low water conc. which attracts water into the plant (osmosis)
desolved salts increase osmotic pressure of soil solution less water from the soil will enter roots
if soil solution becomes to conc. the plants die even though there’s an adequate amount of water and dissolved nutrients
how does low-temperature cause plant stress
low temp results in slow plant growth and development
when temp goes below 0*C freezing damage can occur
what happens when freezing damage occurs
the water within the cell will form crystals and when the temp rises and ice melts the cell contents leak out killing the cell
what are the characteristics of a frost-damaged plant
they will appear dark green and water-soaked at first, later becoming blackened and necrotic. in dry conditions, the tissue may appear white as the water from the broken cell evaporates
how do perennials survive the low temperatures
perennial species will undergo change to become dormant for the winter. how ever perennials can still be damaged by low temperatures
what species is winter burn noticeable in
it is noticeable in ever grees
what is winter burn
it is an injury that occurs when the absorption of water by the roots can’t keep up with the amount of moisture lost by the transportation
what conditions does winter burn occur in
it occurs mostly on sunny days especially when it is windy and when the soil water is frozen and the plant cat absorb it, or is water is short in supply
what does winter burn look like
the injury appears as brown leaf margins or needle tips at the onset of the first period of warm water
what happens if the temperature becomes too high for the plant
the cell proteins coagulate (cook) and the plant cell dies
how is wilting caused
during warm weather, if plants are unable to take up moisture they will wilt and die because the net assimilation rate is negative (photosynthetic gains are less then respiration losses)
how do plants cope with wilting
to cope with the loss of moisture the stomata will close. this results in the plants not being able to perform photosynthesis
what is the stomata
they are openings in plants that allow for the movement of gases. vaporized water leaves through the stomata and CO2 enters.
when is the stomata (of most plants) open
they are open during the day and closed at night
what is the function of guard cells
it’s the cell that surrounds the stomata and opens and closes them
where are the guard cells located
they are present in pairs in the outer skin of a plant most are on the underside of the leaf. but can also be present in stems, petals, etc… but NOT the roots
how does turgor pressure work
guard cells respond to turgor pressure (water pressure) to regulate the opening. this helps regulate the water.
ex. if the plant is wilted, water pressure is low and the guard cells will then be closed. this is beneficial because the plant won’t lose the little water it has
what is the cuticle of the leaf structure
it’s the outer surface of the leaf. there may be a waxy cuticle to reduce moisture loss. the thickness varies among plants and can be affected by the environment
how does temperature affect the cuticle thickness
the hotter it is the thicker it is
what is the term for a singular first stomata
stoma
