Plant Nutrition Flashcards
Explain why plants do not need essential fatty acids, amino acids, or vitamins.
Plants do not need these things because they make all their organic molecules on their own. They use nutrients obtained from the soil through their roots, including nitrogen, potassium, and calcium, to make all their needed fatty acids, AAs, and vitamins
“plants mostly grow out of the air,” explain the reasoning behind this statement.
Plants can be said to mostly grow out of the air because the major nutrients that make up about 96% of a plant mass can be found in our air (hydrogen, carbon, and oxygen). Plants need carbon dioxide in order to convert it to glucose through photosynthesis and oxygen to conduct aerobic transpiration. The products obtained through the process of photosynthesis are then used to make all most all of the other organic molecules that plants need to survive. This is why it can be said that plants mostly grow out of air.
Which 3 elements accounts for 96% of a plant’s mass?
Hydrogen, carbon, and oxygen
Name the primary macronutrients. Explain their uses in a plant.
Nitrogen, phosphorus, and potassium.
Nitrogen- makes amino acids, proteins and chlorophylls
phosphorus- important component of nucleic acids, phospholipids, and ATP
potassium- used in processes including water balance which is needed for the opening/closing of stomata, and various metabolic processes
Explain the difference between elemental and molecular ions.
elemental ions are ions made up of a single element (K+) where molecular ions are made up of more than one element to form a compound (HPO4 2- and NO3 - )
Name two molecular anions important for plants.
HPO4 2- and NO3 - (anions are readily available to plants because they dissolve in water but they can also be easily leached away)
What’s the difference between regolith and soil?
Regolith is the layer of broken and unconsolidated rock and soil material where soil is formed from small particles of rock and organic material components. Soil can be identified by 4 texture categories based on particle size
Explain the importance of soil pH to nutrient availability.
pH plays an important role in nutrient availability due to availability of ions and cation exchange, which causes cations to be released from soil particles when it has a low pH. Plants often prefer soils that are at a pH around 6, or close to neutral, but some plants have adapted to certain soil types. Blueberries, for example have adapted to acidic soils, where rosemary has adapted to alkaline soils
Why has carnivory in plants repeatedly evolved in wet, acidic soils?
Carnivory in plants consistently evolve in wet, acidic soils due to the lack of nutrients present in acidic soils that are necessary for plants to live and function. Acidic soils are more prone to leaching cations in heavy rains, so it is likely that plants needed to evolve other ways to uptake these nutrients in order to survive, including carnivory.
What nutrients are most easily lost with over watering?
Anions because they dissolve in water and
in acidic soils, cations such as magnesium and calcium because they can be leached
Describe how plants use cation exchange to obtain nutrients. Be specific, don’t over-generalize.
Plants use cation exchange in order to uptake the cations that are typically bound to the soil. Protons in the soil water exchange with cations in the soil (such as Mg 2+ and Ca 2+), which allows them to be absorbed by the plants roots. This is why sandy soils are not well suited for growing most types of plants, because they have a poor capacity for cation exchange and anions leach out, making it hard for plants to absorb the much needed cations that are bound to the soil.
Explain how soil texture affects nutrient and water availability.
Soil texture affects nutrient availability because it plays a role in cation exchange capacity. Sandy soils have the lowest capacity for cation exchange, where clay and organic matter have large capacities for cation exchange and therefore higher nutrient availability. Soil texture also affects water availability because it plays a role in how fast water is drained through the soil. Sand has very low water retention, where in clay and organic matter water clings to their charges surfaces and is therefore much more available.
If a plant is growing in sandy soils,
a. What are the advantages?
b. What are the challenges?
The advantages are that there is a high availability of oxygen due to more air containing spaces and roots are able to easily penetrate the soil. The challenges are that there is low water availability because it drains through easily and low nutrient availability because there is a poor capacity for cation exchange and anions leach out.
Explain the role of active transport in nutrient uptake.
plants use active transport to move ions and electrolytes from the soil into their roots. They do this by pumping protons outside the cell, which creates membrane potential which stores energy and cation exchange by lowering the pH outside the cell and therefore knocking cations off soil particles (go against their chemical gradient due to stronger electrical gradient)
Why is the vascular bundle in a root surrounded by the endoderm and Casparian strip?
Because the casparian strip blocks the apoplastic route at the endodermis, forcing water to take an alternate route (either symplastic route via plasmodesmata or transmembrane route) and allows for the regulation of ions entering the xylem, such as regulating Na+
