Mineral Nutrition - 7 Flashcards
Define mineral nutrition
study of how plants obtain and use mineral nutrients
Half of the energy in agricultural production is expended on what
nitrogenous fertilizers
Crops use what amount of the applied fertilizer and where does the remaining go
less than half
leach into surface water/ groundwater, absorb to soil particles or contribute to air pollution
What are plants the traditional means of and proving useful for what
traditional means of recycling animal wastes and useful for removing deleterious materials from toxic-waste
Define essential element
is an intrinsic component in the structure or metabolism of a plant. It is necessary for the completion of the plants life cycle and suffers if in limited supply
What two groups are essential minerals classified into
macronutrients and micronutrients
according to relative concentrations in plant tissues
What is the other way essential minerals can be classified by
according to biochemical role and physiological function into 4 groups
Explain group 1 of essential nutrients by biochemical role
nutrients that are part of carbon compounds (N and S)
create organic compounds (ex. amino acids, nucleic acids)
Explain group 2 of essential nutrients by biochemical role
Important in energy storage or structural integrity (P, Si, and B)
present in plant tissues where elemental group is covalently bound to an organic molecule
Explain group 3 of essential nutrients by biochemical role
Nutrients that remain in ionic form (K, Ca, etc.)
(important as enzyme cofactors, regulating osmotic potentials, controlling membrane permeability).
Explain group 4 of essential nutrients by biochemical role
nutrients involved in redox reactions (Fe, Mn, etc.)
important in reactions involving electron transfer
Why is the biochemical classification arbitrary
because many elements serve several functions and should belong in multiple groups
Crop plants commonly contain only relatively small amounts of ______
nonessential elements
Define nutrient solution
provides all of the elements needed for plants to grow without soil or organic matter
Define hydroponics
techniques of growing plants with their roots immersed in a nutrient solution without soil
What does successful hydroponic culture require
a large volume of the nutrient solution or frequent adjustments of the nutrient solution to account for uptake by roots and changes in pH
a sufficient supply of _____ to the root system is crucial in hydroponics
oxygen
Define nutrient film growth system
another form of hydroponic culture that involves growing plants in a trough and letting solution flow over the roots. it ensures ample supply of oxygen
Define aeroponics
a modification of hydroponics which involves misting roots with nutrients solution and no substrate is required
What is another approach aside from hydroponics and aeroponics that supply intermittent amounts of nutrient solution
ebb and flow system
What are the 4 various types of solution culture systems
- hydroponic growth system
- nutrient film growth system
- aeroponic growth system
- ebb-and-flow system
Define Hoagland solution
a formulation used for nutrient solutions that contains all known mineral elements needed for rapid plant growth
Define chelate and what problem it helps solve in nutrient solutions
they prevent loss of nutrients due to precipitation
ex. iron is provided as a chelate
Why can diagnoses of deficiencies in soil-grown plants be complex (3)
- deficiencies may occur in multiple elements at the same time in different plant tissues
- deficiencies or excess of one element may affect the status of other elements (connected)
- some symptoms look similar to disease symptoms induced by viruses
What is an important clue to diagnose deficiencies and how
the extent to which an element is mobile in plants
ex. N, P, and K can move readily from leaf to leaf and therefore symptoms show up in older leaves first whereas B, Fe, and Ca are immobile and symptoms show up in younger leaves first
Group 1 minerals
Nitrogen and Sulfur
Explain nitrogen as a mineral deficiency
required in greatest amount
inhibits plant growth
shows up as chlorosis (yellow leaves) in older leaves
Explain sulfur as a mineral deficiency
amino acids, coenzymes and vitamins essential for metabolism
similar to nitrogen!!!, chlorosis and inhibits growth. young leaves first, immobile
Explain phosphorous as a mineral deficiency
integral component, sugar phosphates (respiration and photosynthesis) and phospholipids (membranes), ATP, etc.
deficiency in stunted growth, dark green, necrotic spots (dead spots on leaves), older leaves may die, can produce excess anthocyanin (purple colouration)
What minerals are in Group 2
Phosphorous, Silicon, and Boron
Explain Silicon as a mineral deficiency
adequate silicon show enhanced growth, fertility, and stress resistance
lodging (falling over), fungal infection, reinforcement of cell walls and can lesson toxicity of other metals
Explain boron as a mineral deficiency
elongation, nucleic acid synthesis, hormone responses, membrane function and cell cycle regulation
deficiency = black necrosis of young leaves, terminal buds, loss of apical dominance, abnormal fruits, fleshy roots and tubers
What minerals are in Group 3
potassium, calcium, magnesium, chlorine, zinc, sodium, iron , manganese, copper, nickel, and molybdenum
Explain Potassium as a mineral deficiency
regulating osmotic potential, activates enzymes in respiration and photosynthesis
chlorosis, develop into necrosis at leaf tips and margins, leaves curl, and appear on mature leaves
Explain calcium as a mineral deficiency
structural cell walls, secondary messenger, binds to calmodulin
necrosis of young meristematic regions (tips), young leaves appear deformed, meristematic regions die prematurely
Explain Magnesium as a mineral deficiency
activation of enzymes for respiration, photosynthesis, and synthesis of DNA and RNA
chlorosis between leaf veins, older leaves first, senescence and premature leaf abscission (natural detachment)
Explain chlorine as a mineral deficiency
water-splitting reactions of photosynthesis, required for cell division
wilting, leaf chlorosis and necrosis, bronze-like colour, deficiency is rare because are highly soluble and generally available
Explain Zinc as a mineral deficiency
enzymes require Zn, may be required for chlorophyll biosynthesis
reduction in internodal growth (two nodes of a stem) therefore display rosette habit (short, bunchy), occur because loss ability to produce amounts of auxin, chlorosis in older leaves
Explain sodium as a mineral deficiency
CAM plants require for regenerate PEP
chlorosis and necrosis, fail to form flowers, many C3 benefit from low concentration of sodium, stimulate growth through enhanced cell expansion and can partly substitute for potassium as osmotically active solute
Explain iron as a mineral deficiency
synthesis of chlorophyll-protein complexes, involved in electron transfer, reversible oxidation
interveinal chlorosis, younger leaves