Post Midterm Flashcards
Plant Primary Macronutrients
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Plant Secondary Macronutrients
Magnesium (Mg)
Sulfur (S)
Calcium (Ca)
Plant Micronutrients
Boron (B)
Chlorine (Cl)
Manganese (Mn)
Iron (Fe)
Nickel (Ni)
Copper (Cu)
Zinc (Zn)
Molybdenum (Mo)
Micronutrients
Normally found in small amounts
Concentrations of macronutrients range from
1000-450,000 ppm
Iron (Fe)- general info
Biologically relevant form in plants- Fe+2, Fe +3
Concentration in plant: Deficiency- <20, Normal- 20-1000, Toxicity- >2000
Copper (Cu)- General info
Biologically relevant form in plants- Cu+, Cu +2
Concentration in plant (ppm): Deficiency- <10, Normal- 10-25, Toxicity- >25
Zinc (Zn)- General info
Biologically relevant form in plants- Zn+2
Concentration in plant: Deficiency- <10, Normal- 10-120, Toxicity- >120
Manganese (Mn)- general info
Biologically relevant form in plants- Mn+2, Mn+3, Mn+4
Concentration in plant: Deficiency- <90, Normal- 90-200, Toxicity- >200
Molybdenum (Mo)- General info
Biologically relevant form in plants- Mo+4, Mo+6 (in moco or FeMoco)
Concentration in plant: Deficiency- <0.1, Normal- 0.1-90, Toxicity- >90
Boron -General info
Biologically relevant form in plants- B(OH)3
Concentration in plant: Deficiency- <10, Normal- 10-80, Toxicity- >80
Chloride- general info
Biologically relevant form in plants- Cl-
Concentration in plant: Deficiency- >100, Normal- 100-800, Toxicity- <800
Nickel (Ni)- General info
Biologically relevant form in plants- Ni+2
Concentration in plant: Deficiency- >0.05, Normal- 0.05- 10, Toxicity- <10
Micronutrients- general info
narrow optimal concentration range
most are immobile in plants
Micronutrients necessary for chlorophyll production
Iron (Fe) and Manganese (Mn)
Deficiency: poorly mobile elements causes interveinal chlorosis (yellowing)
Iron (Fe)
Abundant, important and largely insoluble
Fe largely oxidized and insoluble
Interveinal chlorosis
Yellowing
the characteristic symptom of iron deficiency
Strategies to improve nitrogen-use efficiency and decrease N pollution
Altering flux into amino acid pools or breeding strategies can enhance nitrogen use efficiency
Iron cells can be found in
Heme
Fe plays central role in electron transport (oxidation/reduction) processes
What is Chelation
The formation of bonds between two or more separate binding sites within a ligand and a single central atom
complex compounds consisting of A central metal atom attached to a ligand in a cyclic or ring structure “clamp”
DTPA chelates
Iron (Fe+3)
Organic acid (Citrate) binds to
Fe
Fe solubilization in soil
to maintain an accessible pool of Fe
Plant root exudate and microbial exudate
Increasing Pi availability
Rhizosphere
soil area around the plant root
yellow- stripe1 mutant
was identified from maize
A lack of chlorophyll
In the 1950s and 1960s, this phenotype is caused by iron deficiency
The transporter (YS) was cloned in 2001
Siderophores:
small metal-binding molecules
generated from bacteria
Phytosiderophores
generated from plants
Silicone
is beneficial to plants, especially under stress conditions
Iron uptake
Strategy I- dicots
Strategy II- monocots
Transport systems that operate across membranes
Symporter
Anitporter
Channels
H+ pump
ABC transporter
Flux (J) crossing biological membrane
Diffusion
Diffusion
Movement of individual molecules of a substance through a from an area of higher concentration to an area of lower concentration
Chemical potential
The sum of the concentration, electrical and hydrostatic potentials (under standard conditions)
Facilitated diffusion
involved in the movement of specific molecule (e.g. ions)
Needs specific channels or carrier proteins
needs no ATP energy for its transport
Facilitated diffusion of “i”
“i” interacts with a “molecule” in the membrane to permit its passive diffusion down its chemical potential gradient
Limited numbers of membrane transporters
membrane proteins are saturated at the high concentration
Glucose Permease
glucose transporter
Plastid glucose transporter
(pGluT; Glucose permease)
located in chloroplast inner envelope
Facilitated Diffusion of Charged Species in biological systems
Diffusion force drives in one direction, while electrostatic force drives in the opposite direction
Nernst potential
Electric field balances the concentration gradient in Activity of “i”
Active transport includes
ATPase, symporter and antiporter
Nitrogen that roots take up
They take up NO3- (Nitrate) or NH4+ (ammonium)
Phosphate transporters
PHT1 for phosphate (Pi) uptake and transport
H+-pumping ATPase:
Primary active transport system
Pumping protons out of the cell
Production of electric pH gradients
Proton (H+) electrochemical gradient
Driving processes of other transporters
Guard cells
Model systems for the study of membrane transport
opening and closing
Development of the plant vascular system
Coordination with the demands on the organism
Phloem and xylem
conducting elements in plants
Xylem
Root to shoot translocation
Phloem
Source to sink translocation
Source tissue
Exporting plant tissues or organs that produces photosynthate (e.g. sugars)- mature and photosynthetically active leave
Sink tissue
Non-photosynthetic developing organ or an organ that does not produce enough photosynthate
Leaf maturation
From leaf tip to the base
If plants are under K-deficient conditions
Substantial growth reduction
yellowing appears on the oldest leaves: K is mobile in plants
Brown necrotic lesions develop within the yellow parts and eventually spread to cover the entire leaf blade
Sieve tube
the functional units for long distance translocation of plant materials
stacked sieve elements
Sieve plate
a perforated wall between the sieve elements
Mature sieve elements contain
- Structural phloem specific proteins (P-proteins)
- Endoplasmic reticulum (ER)
- Mitochondria
- Sieve element plastids
Mature sieve elements DO NOT contain
- Nucleus
- Vacuole
- Golgi bodies
- Chloroplast (at the shoot)
P-proteins and Callose
protection mechanism in phloem
P protein
Sealing off damaged sieve elements by plugging up the sieve plate pores
quick plant response (short term solution)
Callose
B-(1,3)-glucan
seal off damaged sieve elements
long-term solution
Heterotrophic shoot
Assimilate “sink”
Autotrophic leaf
Assimilate source
Heterotrophic root
Assimilate “sink”
Sucrose loading into minor leaves
1) Symplasmic sucrose loading model
2) Apoplasmic sucrose loading model
Symplasmic sucrose loading model
sucrose moves through the plasmodesmata from the mesophyll cells to the phloem
Can all sugar forms move through the phloem?
“nonreducing sugars (less reactive) can be transported via the phloem”
Generally not reducing sugars
Glucose, Mannose and Fructose (reducing sugars) contain reducing groups (aldehyde and ketone group)
Chemically too reactive to be translocated through the phloem
Sucrose
the most common form of sugar
translocated through the phloem
Aphids feed directly from
phloem
What is being loaded/translocated through phloem?
water
photosynthate (raffinose group-sucrose):Sugars
Specific amino acids
Ions
Metabolites
Hormones (Auxin, gibberellic acid, etc.)
Proteins (role in signaling and SE maintenance)
RNA
(Information superhighway)
Chlorophyll
Reflection of green wave length (plants are green)
Endergonic (energy in) reaction
potential energy of substrate < product
Exergonic (energy out) reaction
Potential energy of substrate>product
Pyrenoid
carbon-fixing reactions take place
two types of photosynthesis
oxygenic photosyntehsis
anoxygenix photosynthesis
Oxygenic photosynthesis
Removal of electrons from H2O->release of O2
Reduction of CO2 to carbohydrate (3 carbon sugar)
Plants, algae and certain types of bacteria (cyanobacteria)
Anoxygenic Photosynthesis
Do Not extract electrons from water:
Plastids and chloroplasts
Essential organelles for most plant cells
Etioplast
dark grown photosynthetic tissue
no chlorophyll
Developed plastid from the proplastid when plants are grown in dark
Proplastid
undifferentiated
colorless
seeds, embryonic, meristems and reproductive tissues
Chromoplast
red and yellow pigment (carotenoids)
Flower (petal), fruit
Identity and abundance of plastids are controlled by
developmental and environmental cues
Light induces conversion from
Etioplast to chloroplast
Grana stacks in the thylakoids
Speciality of land plants