Plant Nutrition Flashcards
As plant grows what is the source of the raw materials that compose a plant?
water atmosphere and soil
sugars made by plants use
carbon and oxygen from the atmosphere
hydrogen from water
sugars made by photosynthesis is used in constructing
primarily carbohydrates
what is the direction of water movement through the plant?
from roots to leaves
What nutrient source contributes the most to the dry-weight biomass of these trees?
the atmosphere or air
root hairs greatly increase…
a roots absorptive surface
In what ways can water and solutes move through the root’s epidermis and cortex?
- through cell wall/plasma membrane
2. hydrophilic intercellular space
what is the casparian strip?
a selectively permeable plasma membrane that controls the substances that enter the vasculature of a plant
What cells form the xylem?
tracheid’s and vessel elements
xylem cells are both ______ and _____ when mature?
dead
hallow
describe tracheids..
long and thin with tapered ends
describe vessel elements..
thick and shorter w/ opening in the ends of cells
what pulls water up the xylem?
transpiration
xylem sap flows within the xylem and is pulled by
transpiration
sap movement is aided by _______ and ______
cohesion and adhesion
define transpiration
evaporative water loss
loss of water from the leaves causes negative pressure in the
mesophyll cells
define cohesion
forces that hold two of the same molecule together
define adhesion
forces that hold two different molecules together
water is a ______ molecule?
polar
50 gallons of water are used by one corn plant in a ______ and by one rainforest tree in a ____.
summer
day
What controls transpiration of a cell?
guard cells
When plants need CO2 guard cells?
swell and bow outward
To conserve H2O plants?
close the stomata
define turgor pressure
loss of K+ followed by the flow of water
What are some of the evolutionary adaptations of the stoma?
- placement
- number/ size
- when to open
define trichomes
leaf hairs
define hydrotropism
how roots search for water
What is the physical barrier in the root that regulates the flow of water to xylem via cell walls?
the casparian strip
what force is responsible for the cohesiveness of water?
the hydrogen bonding between water molecules
A hot, dry summer will reduce crop yields because?
carbon dioxide is reduced by the stomata closing to prevent excessive water loss
What are the plants two separate transport systems?
- phloem
- xylem
phloem functions to transport
photosynthesis products from where they are made/stored to where they are needed
where are the sieve-tube elements growing?
in the secondary phloem
What do the sieve-tube elements become?
bark
what is the pressure flow mechanism?
the process by which sap flows from the sugar source to a sugar sink
describe what occurs at a sugar source?
- sugar is loaded into a phloem tube
- water follows
- pressure inside tube increases
describe what happens at a sugar sink?
- sugar is removed
- water follows
- pressure inside tube decreases
increase pressure at the sugar source and decreased pressure at the sugar sink causes phloem sap to…
flow from the source to the sink
At the sugar source there is _____ transport of sugar and ______ of water
- active
- osmosis
In the summer _____ is the sugar sink and _____ are the sugar source.
taproot
leaves
under which condition would transpiration be most rapid?
hot, dry weather
the sugar sink in roots is a result of?
active transport of sugars from phloem to root cells
in early spring are maple roots a sugar source or a sugar sink?
sugar source
define macronutrients
nutrients like carbon and nitrogen that are needed in large amounts to build organic molecules
define micronutrients
nutrients needed in smaller amounts such as iron and zinc that act as cofactors for enzymes
hydroponic cultures allow for
very specific manipulation of both macro and mirco nutrients
Can plants use all forms of a nutrient?
NO
reddish purple coloring on the outside of leaves indicates
shortage of phosphate
orange/yellow lining on the outside of leaves indicates
Potash deficiency
orange/yellow lining on the inside of leaves indicates
nitrogen deficiency
strips along the veins of leaves indicates
magnesium deficiency
N2 _____ be used by plants whilst NO3- and NH4+ ______ be used by plants
CANNOT
CAN
what are the two basic types of fertilizers?
- organic
- inorganic
in order to determine if a potential nutrient is essential for a plant you would perform a
hydroponic test
compost is considered a
organic fertilizer
define humus
decaying organic material
humus provides ______ and supports ….
nutrients
the growth of organisms that enhance soil fertility
layers of soil
- topsoil
- subsoil
- bedrock
topsoil is composed of
rock, living organisms, humus
subsoil is composed of
fine clay, nutrients from top soil
bedrock is composed of
mostly rocks
define anions
negatively charged ions
define cations
positively charged ions
what type of ions tend to drain out of soil?
anions
what occurs during cation exchange?
root hairs release H+ causing cation from soil to become displaced allowing the root hairs to absorb the free cations
What are some aspects of good soil management?
- water conserving irrigation
- erosion control
- prudent use of herbicides/ fertilizers
define erosion
the blowing/washing away of soil
erosion causes a loss of
nutrients and substrate in the top soil
sinkholes are caused by the
over exploitations of water
over-fertilization causes
nutrient runoff into water ways causing algae blooms
Which would most likely leach from the soil?
NO3-
commercial inorganic fertilizers have greatly increased agricultural productivity. What is an advantage of using inorganic rather than organic fertilizers?
nutrients are released faster from inorganic fertilizers
organic farming promotes biological diversity by
- maintaining soil quality
- providing habitat for predators
- avoiding genetically modified organisms
characteristics of sustainable agriculture
- conservation-minded
- environmentally safe
- can de practiced for many years without harming the environment
what is the primary goal of organic farming?
to achieve sustainable agriculture
are organic crops healthier?
according to meta-analysis studies, NO