theme 4 Flashcards
(67 cards)
how many essential elements are there for plants? what are the big ones?
elements that are required for proper functioning of the organism
-N
-P
-K
Ca
Mg
Fe
what are macronutrients
elements and plant needs in large quantities
-C, H, O from air
-N
-P
-K
-S
-Ca
-Mg- all of these are required to be dissolved in water
what are micro nutrients
elements only needed in small quanities
-Cu
Cl
Ni
what is the form of nitrogen that plant prefer to use
NO3-, but then the plant converts it back into NH4
What is the nitrogen cycle
N2 atmos–> NH4 via bacteria in soil or ammonifociation via bac of decaying matter–> NO3- via nitrification via bacteria
why is N important?
allows plant to grow
how is nitrogen taken out of the soil?
harvesting crops (disrupt soil) or the shifting of land for agriculture
how is nitrogen content improved in soil
-crop rotation
fertilizer- domination during the 1940-1970
what are lodging plants
during the 40-70s when fertilizer was surplus, plants grew wayyyy to tall and were prone to falling over and breaking
how much nitrogen from fertilizer used? lost?
only 10% is taken by plants, 90% is lost as runoff
what happens with excess N in water?
Eutrophication (algal blooms). this causes a depletion of O2. the ecosystem is harmed
eutrophication
the enrichment of ecosystems with chemical nutrients such as N and P
what are the grains that are found in soil?
sand 0.02-2mm
silt 0.02-0.002mm
clay <0.002
what is soil solution
a combo of water and its dissolved components that coat particles and fills pore spaces
what do clay and humus particles do to water moles?
negatively charges them- makes it alkiline
what is cholorosis
the yellowing od plant tissues due to a lack of chlorophyll
how are minerals (cations) exchanged between roots/soils
the roots produce H+ ions which will enter the solid, and displace the nutrients (K+, Ca2+ and Mg2+) which in turn are uptaken by the roots
or the roots and CO2 via respiration which are turned into H2CO3 when interacting with H2O, the H+ from this mole displace the cations in the soil and are uptaken by the roots
how are anions exchnaged between soil and roots
anions move freely in the negatively (alkaline) charged soil and easily move into the roots
what is the common pH of soil
8-9
what is alkaline soil
a basic soil whcih can easly leach anions
what is an acidic soil
a soil which cations leach out easily
passive transprt
requires no energy to move a substance. it moves down the [] gradient (with the membrane potential)
-eother moves across the membrane )O2, H2O or CO2) or through a protein
active transport
requires the expenditure of ATP to move a substance (against the gradient)
what are two mechanisms that plants use to increase nutrient uptake
root hairs- greatly increase SA
-Mycorrhizae- a symbiotic relationship with fungus and roots (fungus mobilizes phosphorous)