Crop Phys Nutrients

Macronutrients (5) - post exam 2

• K

• Ca

• Mg

• P

• S

Micronutrients (8)

• Cl

• Fe

• B

• Mn

• Zn

• Cu

• Ni

• Mo

Mobile Nutrients (8)

• Cl

• Zn

• Mo

• Ni

• Mg

• K

• S

• P

Immobile Nutrients (5)

• Fe

• B

• Mn

• Ca

• Cu

Chlorine

Type: Micro

Uptake: Cl-

Form in Plant: Cl-

Mobility: Mobile

Function:

• Osmolyte

• oxygen evolving complex (PSII)

• stomatal aperture regulation

• activation of tonoplast H+ atpase

Deficiency:

• Wilting and chlorosis of leaf tips

• thickened roots near root tip

Iron

Type: Micro

Uptake: Fe2+ and Fe3+

Form in Plant: Fe2+ and Fe3+, enzyme component, iron chelates

Mobility: Immobile

Function:

• Redox system proteins

• protein synth

• chloroplast development

• photosynth

• respiration

Deficiency:

• leaf chlorosis

• severe deficiency causes white leaves

Boron

Type: Micro

Uptake: Bo3^3-

Form in Plant: Complexed in cell walls, with certain sugars, and cross linking of pectin walls

Mobility: Immobile

Function:

• Cell elongation

• nucleic acid synthesis

• hormone responses/auxin regulation

• membrane function

• pollen germination and pollen tube growth

Deficiency:

• damaged growing tip

• shorter internodes

• flower and fruit drop

• reduction in seed and fruit set

• increased susceptibility to bacterial and fungal infections

• brittle and stiff stems

• cracking of leaves

• cracking and rot of tap root crown

Manganese

Type: Micro

Uptake: Mn²⁺

Form in Plant: Free ion, PSII oxygen evolving complex, Manganese superoxide dismutase

Mobility: immobile

Function:

• Enzyme activation

• oxygen evolving complex

• photosynth

• carb metabolism

• lipid metabolism

Deficiency:

• dark green veins and light yellow to white interveinal leaf tissue

Zinc

Type: Micro

Uptake: Zn²⁺

Form in Plant: Free ion, complexed to organic molecules, zinc containing enzymes

Mobility: mobile

Function:

• enzyme component

• enzyme activation

• protein synth

• carb metabolism

• auxin metabolism

• dna rep and gene expression

Deficiency:

• Reduction of internode growth

• small distorted leaves with wavy margins

• interveinal chlorosis and white necrotic spots in some species

• terminal die back in trees

Nickel

Type: Micro

Uptake: Ni²⁺

Form in Plant: complexed, enzymes

Mobility: mobile

Function:

• Urease

• hydrogenase

Deficiency:

• leaf marginal chlorosis

• premature senesence

• small cupped, heart shaped leaves

• rosetting

Molybdenum

Type: Micro

Uptake: MoO4^2-

Form in Plant: MoO4^2- , enzyme component

Mobility: mobile

Function:

• redox rxns

• nitrate reductase

• nitrogenase

• xanthine oxidase

Deficiency:

• symptoms of N deficiency

• stunted growth

• chlorosis

• small and irregular leaf blades

Potassium

Type: Macro

Uptake: K+

Form in Plant: K+

Mobility: Mobile

Function:

• phloem unloading

• binding of trna to ribosome

• protein synth

• stomatal aperture regulation

Deficiency:

• leaf tip burn

• inter veinal necrosis and chlorosis in advanced stages

• leaves may crinkle and curl

Calcium

Type: Macro

Uptake: Ca2+

Form in Plant: Ca2+, free ion

Mobility: immobile

Function:

• structural component of cell wall, crosslink pectins in cell wall

• membrane stabilisation

• cellular signaling

• enzyme activation

• charge balance

• osmoregilation

Deficiency:

• necrosis of young meristematic regions

• chlorosis and downward hooking of young leaves

• growth stunting

• blossom end rot

Magnesium

Type: Macro

Uptake: Mg2+

Form in Plant: Mg2+, central chlorophyll atom, Mg-ATP complex

Mobility: mobile

Function:

• chlorophyll

• protein synth

• enzyme activation

• carb partitioning

• formation and maintenance of RNAs and DNA

• atp synth

Deficiency:

• interveinal chlorosis

• yellow to white leaves when severe

• premature leaf abscission

• increased shoot to root ratio (carb flow to roots limited)

• zebra striping in corn

Phosphorous

Type: Macro

Uptake: H₂PO₄- and HPO₄^2-

Form in Plant: HPO₄^2-

Mobility: mobile

Function:

• structural element of dna, rna, and phospholipids

• energy transfer (atp)

• membranes, phospholipid bilayer

Deficiency:

• young leaves stunted

• dark green leaves

• excess anthocyanins

• long root hairs

• proteoid roots

Type: Macro

Uptake: SO₄^2-

Form in Plant: cystine

Mobility: Mobile

Function:

• amino acids

• protein structure (disulfide bridges)

• iron sulfur clusters in electron transport

Deficiency:

• chlorosis in young and mature leaves

• growth stunting

• brown necrotic spots along petiole under severe deficiency

Potassium Assimilation

Low Affinity: high K concentration in soil, uptake is slow/low rate

High Affinity: low K concentration in soil, uptake is fast/high rate

Sulfur uptake

• TLDR: Sulfate → cystine

• Sulfate (reduced to) → APS (reduced to) → sulfagluthionate (reduced multiple times) → sulfite (converted to) → cystine

Iron Dicot Strategy Uptake

• rhizosphere pH is reduced

• reductants trap Fe3+ in soil, reduce it to Fe2+ and move it into the cell

• requires atp

Graminaceae Iron Uptake Strategy

• Release of phytosiderophores

• phytosiderophores trap Fe3+ and move into cell as a whole complex

• inside cell, Fe3+ split from phytosiderophore

Nutrients with deficiencies of chlorosis in young leaves (immobile)

• Fe

• Mn

• Cu

• Ca

Nutrients with deficiencies of chlorosis in older leaves (mobile) (7)

• S

• Mg

• K

• Mo

• Ni (margins)

• Zn

• Cl

nutrients evolved in redox reactions

• Fe

• Cu

• Mo

nutrients involved in enzyme activation

• Zn

• Mn

• Ca

• Mg