1.77k likes | 5.43k Views
Mineral nutrition. Elements essential to growth and development of plants and the criteria for establishing the essentiality . Mineral nutrition. METHODS TO STUDY THE MINERAL REQUIREMENTS OF PLANTS. HYDROPONICS- JULIUS VONSACHS. Mineral nutrition. Essential mineral elements . Criteria
E N D
Mineral nutrition Elements essential to growth and development of plants and the criteria for establishing the essentiality
Mineral nutrition METHODS TO STUDY THE MINERAL REQUIREMENTS OF PLANTS HYDROPONICS- JULIUS VONSACHS
Mineral nutrition Essential mineral elements • Criteria • Absolutely necessary- life cycle of plant is affected • Specific • Direct involvement in metabolism Macro nutrients and micronutrients
Mineral nutrition MACRONUTRIENTS Present in large amounts C, H, O, N, P, S, K, Ca, Mg
Mineral nutrition MICRONUTRIENTS Trace elements- needed in small amounts Fe, Mn, Cu, Mo, Zn, B, Cl, Ni
Mineral nutrition MICRONUTRIENTS- other classification • Structural elements of cell • Components of Energy compounds • Activate or inhibit enymes • Affect osmotic potential
Mineral nutrition ROLE OF MICRONUTRIENTS • NITROGEN: Absorbed asNO3- needed for meristamatic cells • Component of protein, NA,vitamins,hormones Phosphorus: as phosphate ions- component of cell membranes, certain proteins, NA, nucleotides, required for phosphorylation
Mineral nutrition ROLE OF MICRONUTRIENTS • Potassium: Absorbed potassium K+ ions • Needed in the meristerm, bud, leaves and root tips. • Anion-cation balance, opening and closing of stomata, turgidity of cells Calcium: as Ca 2+ ions. Essential for meristamatic tissues, synthesis of cell wall, formation of mitotic spindle, and metabolic activities
Mineral nutrition ROLE OF MICRONUTRIENTS • Sulpher: in the form of sulphate. Present in aminoacidscysteine and methionine, coenzymes, vitamins and ferredoxin Magnesium: as Mg 2+ activates enzymes for respiration, photosynthesis, and synthesis of RNA ANA DNA. Constituent in the ring structure of chlorophyll and maintain ribosome structure
Mineral nutrition ROLE OF MICRONUTRIENTS • Iron: as Fe3+. Needed in large amounts than other micronutrients. Constituent of protein, essential for the formation of chlorophyll Manganese: Mn2+. Activates enzymes in respiration and photosynthesis. Splitting of water during photosynthesis to liberate O2
Mineral nutrition ROLE OF MICRONUTRIENTS • Zinc: Zn2+.synthesis of auxin Copper: Cu2+ metabolism Boron: uptake of Ca.pollen germination, cell elongation, cell differentiation, etc. Molybdenum: enzymes in nitrogen metabolism Chlorine: water splitting, and anion-cation balance
DEFICIENCY SYMPTOMS Critical concentration: the concentration below which the growth is retarded Morophological changes due to deficiency- deficiency symptoms. Deficiency symptom first appear in older parts in case of actively mobilised elements – nitrogen, potassium And in young tissues in case of relatively immobile- sulpher, calcium
DEFICIENCY SYMPTOMS Premature leaf fall. Stunted growth, inhibition of cell division Necrosis and chlorosis Ca ,Mg Cu K N K Mg S Fe Mn Zn Mo
Toxicity of micronutriens Concentration that reduces dry wight by 10% is toxic. Excess of one element inhibit uptake of another one- manganese toxicity- brown spots surrounded by chlorotic veins – affect uptake of Mg Fe and Ca
Mechanism of absorption of elements Absorption has two phases First into the outer space- apoplast pathway Second into the inner space- symplast pathway Movement of ions is called flux Inward- influx Outerword- efflux
Translocation of solutes Translocation takes place through transpirational pull
Soil- reservoir of minerals Majority nutrients get through weathering and breakdown of rocks. Soil harbours nitrogen fixing bacteria, other microbes, holds water, supplies air to roots.
nitrification Ammonia NO2 by nitrosomonas and nitrococcus. NO2 NO3 by nitrobacter
Nitrate is reduced to ammonia in plants and transported to leaves denitrification Nitrate in soil Nitrogen by Pseudomonas and Thiobacillus
Biological nitrogen fixation Only certain prokaryotes are capable of fixing nitrogen- called biological nitrogen fixation Nitrogenase enzyme helps fixation Azotobacter, Beijernickia, Rhodospirillum, Bacillus are microbes fixing nitrogen Anabaena and Nostoc- cyanobacteria
Symbiotic biological nitrogen fixation Frankia- symbiotic on non-leguminous Alnus
Nitrogenase enzyme and nitrogen fixtion N2+ 8e- + 8H+ 16 ATP 2NH3+H2+16ADP=16Pi NITROGENASE IS HIGHLY SENSITIVE TO OXYGEN. NEEDS ANAEROBIC CONDITION. NODULE CONTAIN OXYGEN SCAVENGER LEG -HAEMOGLOBIN
Fate of ammonia Ammonia is used for synthesis of amino acids 1. Reductive amination- amonia reacts with α-ketoglutaric acid and forms glutamic acid 2. Transamination- transfer of amino group from one aminoacid to ketogroup of another by transaminaze enzyme