Nutrient Uptake by Root and Leaf and Nutrient Distribution

Nutrient

Soil solution, soil particle, soil colloid

Nutrient Donnan Free Space Cation Exchange Capacity (CEC)

IN XYLEM Plasmodesmata (Symplastic Pathway) plasma H2O Tip (Ca) Leaf Next cell Plasmalemma Cytoplasm Tonoplast Vacuole Plasmodesmata (Symplastic Pathway) plasma Endodermis Cortex Epidermis Root hair Soilparticle Soil solution

Factors affecting Nutrient 1. Ion diameter ION UPTAKE BY ROOT Root Interception (Soil – root Surface) Mass flow (Transpiration Stream) Diffusion (Conc. Gradient) Factors affecting 1. Ion diameter radius Li+ > Na+ > R+ > Ce+ Uptake rate

Nutrient 2. Valency 3. Metabolic activity 4. Interaction Between Ion Uncharged mol : <Cat+ , An- < Cat2+, An2-< Cat3+<An3- Uptake rate 3. Metabolic activity Energy Respiration Active Uptake (O2, Temp., CHO- Light) 4. Interaction Between Ion - Competition (same valency & ion size) - Competition K+ inhibit NH4+ uptake Ca2+ & Mn2+ inhibit Mg2+ uptake Ce- inhibit No3- (น้ำประปา, น้ำทะเล)

7. Cation – Anion Relationship 8. External Concentration 5. pH (H+ , OH+ ) pH : uptake K+ NH+ No3- 6. Ion Synergism Ca2+ K+ uptake – low pH K+ uptake – high pH 7. Cation – Anion Relationship Electrical charge balancing 8. External Concentration 9. Internal Concentration & Nutrition Status 10. Plant Development & Nutrifional Requirement

TRANSLOCATION OF ION IN XYLEM Diffusion (Cation exchange, , valency, Organic compounel Mass flow (Transpiration stream) Resorption (Companion cell) Resorption (Accumulation, Phloem) Plant age Time of day (Morning, afternoon, Dark, Light) External Concentration Internal Concentration Uncharged Molecule > ions

(Highly hydrated Polysaccharide) TRANSLOCATION OF ION IN PHLOEM 1. Components : - Sieve tube elements - Companion cells - Parenchyma cells Sieve Plate Pore (Plasmodesmata) Callose (Highly hydrated Polysaccharide) Swelling - heat treatment Blocking - mechanical injury of phloem

Nutrient 2. Composition of phloem sap : (using aphid) exudate : pH 7-8 Solids 15-25% drymatter Sucrose 90% Organic acid Organically bound N K>P > Mg > S > Ca (Micro.-rare) Cation > Anion (Amino acid for compensation)

Nutrient 3. Mobility of mineral element in phloem Mobile Intermediate Immobile K Fc Li Ru Mn Ca Na Zn Str Mg Cu Ba P Mo B S Cl

Active Leaf Senescence Leaf (elements) Nutrient 4. Direction of Phloem Transport Xylem : Unidirection Phloem : Bidirection (Source Sink) Active Leaf Senescence Leaf (elements) * * * - Root, Shoot apice, fruit, seed, Stressed tissue

Nutrient * 5. Mechanism of Translocation Sink – Source Relationship Others - Retranslocation (Shoot root) (Toxic elements : Na+, Cl-) Transfer between Xylem – Phloem (Active transport from xylem to phloem of elements) good for translocation to active sites *

Nutrient 6. Remobilization (except Ca, B) Seed germination, Insufficient supply, Interupted supply, Reproductive stage, Senescence Nutrient Symptom Remo. N, K, Mg, P Old Leaves Very good S Young Leaves Insuf. Fc, Zn, Cu, Mo Young Leaves Very low B, Ca Young Leaves & apical meristem nil

Nutrient ION RELEASE Leaching Guttation Excretion Senescence organ Exchange (Ion Balance)

Nutrient MOBILITY Mobile Intermediate Immobile K Fe Ca Na Mn B Mg Zn Li P Cu Sr S Mo Ba Cl Rb

Nutrient ION UPTAKE BY LEAVES & OTHER AERIAL PARTS 1. Uptake of gases through stomata CO2, O2 gas exchange Mineral nutrient in form of gases : SO2, NH3, NOx SO2 uptake through stomata SO42- uptake through root Competitive of SO2 to CO2 in C3 – Pn pathway (RubP)

Nutrient 2. Uptake of Solute 2.1 Uptake through stomata 2.2 Structure & Function of Cuticular layer Structure : Cuticular layer = layer of wax & Cutin & Pectin, hemicellulose & Cellulose Cutin = a condensation product of C18 hydroxy fatty acids with semihydrophilic properties Function : Protect the excessive water loss Protect against excessive leaching of solutes by rain

Nutrient 3. Factors affecting uptake rate 3.1 External factors Concentration, Valency, Temperature Environments (thickness of C. I.) - shade, unshaded leaves Light, temperature water evaporation from foliar spray 3.2 Internal factors Nutritional status of plant (deficient > well supplied) Leaf age (old uptake ) Metabolic activity Sink activity Membrane permeability Thickness of cuticle

Nutrient 4. Foliar Application of Mineral Nutrients more rapid than root application more specific 4.1 Problems: 1) Low penetration rate (esp. thick cuticle) 2) Run – off from hydrophobic surface 3) Washing off by rain 4) Rapid dry of spray solution 5) Limited rate of retranslocation (ex. Ca2+) 6) Limited amounts (Concentration & leaf burn) aver. 1% except. Urea 10%

Nutrient 4.2 When to apply through leaf Low nutrient availability in soil (pH, soil type, fixation, solubility) Dry topsoil Decrease in root activity during reproductive stage Increase in protein content of cereal seeds Increase in Ca content of plant parts (Fruit, tip) end