1. Elements essential to growth and development of plants and the criteria for establishing the essentiality

2. HYDROPONICS- JULIUS VONSACHS

3. Criteria Absolutely necessary- life cycle of plant is affected Specific Direct involvement in metabolism

4. Present in large amounts

5. Trace elements- needed in small amounts

6. Structural elements of cell Components of Energy compounds Activate or inhibit enymes Affect osmotic potential

7. NITROGEN: Absorbed asNO3- needed for meristamatic cells Component of protein, NA,vitamins,hormones

8. 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

9. Sulpher: in the form of sulphate. Present in aminoacids cysteine and methionine, coenzymes, vitamins and ferredoxin

10. Iron: as Fe3+. Needed in large amounts than other micronutrients. Constituent of protein, essential for the formation of chlorophyll

11. Zinc: Zn2+.synthesis of auxin

12. 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

13. Premature leaf fall. Stunted growth, inhibition of cell division

14. Concentration that reduces dry wight by 10% is toxic.

15. Absorption has two phases First into the outer space- apoplast pathway Second into the inner space- symplast pathway

16. Translocation takes place through transpirational pull

17. Majority nutrients get through weathering and breakdown of rocks. Soil harbours nitrogen fixing bacteria, other microbes, holds water, supplies air to roots.

20. 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

24. NITROGENASE IS HIGHLY SENSITIVE TO OXYGEN. NEEDS ANAEROBIC CONDITION. NODULE CONTAIN OXYGEN SCAVENGER LEG -HAEMOGLOBIN

25. Ammonia is used for synthesis of amino acids