Functions and deficiency of Iron, boron and zinc
- 1. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms Essential Elements: Forms, Occurance, Functions and Deficiency Symptoms Krishna Aryal Asst. Professor (Soil Science) Krish.aryal2014@gmail.com 1
- 2. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 2 Iron content of soil • Principle form of Fe in soils in hydrous oxide; exists in soils as Fe3+ (ferric, oxidized, low solubility) & Fe2+ (ferrous, reduced, & available). • Soil pH, aeration, organic matter and plant adaptation influences the availability of iron. • Common Fe containing minerals Olivine: [(MgFe)2 SiO4, Pyrite: FeS, , Siderite: FeCO3, Limonite: FeOOH.nH2O, Hematite: Fe2O3, Goethite: FeOOH, Magnetite: Fe3O4 Iron Forms and occurrence • Absorbed by plants roots as ferrous ion (fe2+ ), ferric ion (fe3+) and other chelated form. • The conc. of Fe in plants range from 100-500 ppm which is regarded as sufficient for crop production.
- 3. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 3 Functions of Fe in plants • It helps in the synthesis of chlorophyll. • Structural component of porphyrin molecules like cytochromes, hematin, hemes, ferrichrome and leghemoglobin. These substance are involved in oxidation- reduction reaction in respiration and photosynthesis. • Structural component of non heme compounds like ferredoxins. • It plays an essential role in the nucleic acid metabolism. • Constituent of enzyme systems Eg: cytochrome oxidase, catalase, nitrogenase reaction in plants. • Component of flavoprotein like FMN = Flavin mono nucleotides FAD = Flavin Adinosine Dinudeotide.
- 4. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 4 Deficiency of Fe in plants • As Fe is immobile in the plant, its deficiency is manifested on young leaves. • Interveinal chlorosis appearing first on the younger leaves with leaf margins and veins remaining green. • In later stage burning of the chlorotic leaves start from the tips and margin, spread inwards. • The chlorotic leaves may become white and the leaf tissues devoid of chlorophyll die.
- 5. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 5 • Reddish-brown necrotic spots along the leaf margins of young shoots in tree crops. • In Brassica necrotic terminal buds at early seedling stage. • Stalks are short & slender. • Def. symptoms of iron are most frequently seen in crops growing in calcareous or alkaline soils (blenching of rice seedlings in calcareous soil).
- 6. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 6 Boron content of soil • B is present in soil solution in the form of boric acid (H3BO3) anionic form viz., dihydrogen borate (H2BO3 -), monohydrogen borate (HBO3 2-) under acidic conditions and borate BO3 3- under high pH condition. • B conc. in soil vary from 2 to 200 mg kg-1, but generally less than 5-10% is in a form available to plants (Diana, 2006). • Common B containing minerals Tourmaline: [Na(Mg.Fe)3 Al6(BO3)3(SiO3)6(OH)4, Ludwigite(Mg2FeBO5), Katoite Mg(BO3)2 Boron Forms and occurrence • Unique non metal among micronutrients • Absorbed by plants roots as undissociated boric acid (H3BO3). • The conc. of B in plants range from 2-75ppm.
- 7. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 7 Availability of B depends upon Soil texture : Fine textured soils added B for longer period than coarse textured soil. Type of clay : Mica > montmorilonite > kaolinite Soil pH and liming : Less avail to plants with increase pH heavy liming lead to greater adsorption and reduced B uptake Organic matter : Availability of B in surface soil is high compared to subsurface soil. Interactions with other cations : Occurrence of Ca in alkaline soil with restrict B availability. Increased K rates causes B toxicity. Soil moisture : Restricted moisture supply reduce the B availability in the root zone.
- 8. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 8 Functions of B in plants • Development & growth of new cells in meristem. • Responsible for cell wall formation and stabilization, lignification and xylem differentiation. • Influences carbohydrate metabolism, RNA metabolism, IAA metabolism, Phenol metabolism. • Plays a role in pollen germination and pollen tube growth. • Translocation of Sugar, starch, N & P (to seeds). • Facilitates the transport of K in guard cells as well as stomatal opening
- 9. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 9 • Helps in nodule formation in legumes. • Gives resistance for pest and disease infection. e.g. virus, fungi & insects • Helps in protein synthesis for formation of plant hormones. • It has role in hormone movement and action • Enhances rooting of cutting through oxidation process.
- 10. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 10 Deficiency symptoms of B in plants • As B is immobile in the plant, its deficiency is manifested on young leaves. • Young leaves may be deformed, appear like a “rosette”, • Internodes become shorter and give bushy apperance. • Flowering and fruit development are restricted. • Premature seed or fruit drop.
- 11. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 11 • Corky apple, uneven thickness of peel of citrus, lumpy & gummy fruits • Darken (black heart) in root crops such as radish turnip, potato etc. • In trees, shoot tips may die leading to multiple lateral branches and reduced lignifications of wood may cause branches to weep. • In cauliflower & broccoli, leaves rolling & deformed buds, hollow stem, browning of curds caused dead heart
- 12. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 12 • Poor-pollination in corn leads to small-undeveloped cobs in one stalk, barren cobs, barren stalks • Wheat Sterlity.
- 13. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 13 Zinc content of soil • It exists in soil solution as Zn2+, as exch. Zn, organically complexed Zn & Zn substitute for Mg in the crystal lattice of silicate clays. • Its conc. in soil is 10-300 (average 50 ppm). • Most of the Zn in soil is found in ferromagnesium minerals (Augite, Hornblende & Biotite) Zinc Forms and occurrence • Plant roots absorb Zn as Zn2+ & as a compound of natural & synthetic molecular complex. • Soluble zinc salt & zinc complexes can also enter the plant system directly through leaves. • Normal conc. of Zn in plant tissue ranges from 25-250 ppm.
- 14. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 14 Functions of Zn in plants • Zinc is a constituent of three enzymes viz., Alcoholic dehydrogenase, carbonic anhydrase, superoxide dismutase (SOD) which regulates various metabolism in plants. • Zn is involved in the synthesis of indole acetic acid, metabolism of gibberellic acid and synthesis of RNA. • Promotion of synthesis of cytochrome–C. • Transportation of carbohydrate & regulates sugar consumption. • Helps in photosynthesis & N- metabolism.
- 15. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 15 • Synthesis of Radical oxygen species (ROS) scavenging enzymes.- Gultathion peroxidase. • It activates enzymes in amino acids & protein synthesis. • It is necessary for starch formation & proper root development. • Influences the rate of seed & stalk maturation. • Necessary for the formation of chlorophyll & carbohydrates. • The presence of adequate amounts in the tissue enables the plant to withstand lower air temperatures.
- 16. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 16 Deficiency symptoms of Zn in plants • It is not readily redistributed from old leaves (immobile element), deficiency symptom first appear on expanding leaves. • Zn deficient plants are stunted. • Malformation of fruit often with little or no yield. • Rosetting & clustering of leaves at the top of fruit trees, shortened internodes, leaf size decreased, leaf tip & interveinal necrosis.
- 17. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 17 • In corn & sorghum, Zn def. is called white bud, in cotton, it is known as little leaves, in citrus & grasses mottled leaves, khaira disease in rice (bronzing), Fern leaves of potato. • Browning of nut trees, yellows of walnut, rosette of apple & dead spot on tobacco leaf.
- 18. Institute of Agriculture and Animal Science (IAAS) Prithu Technical College Deukhuri, Dang SSC-121 Essential Nutrients : Forms, Occurance, Functions and Deficiency Symptoms 18