Phosphorus (p) - macronutrients, Biology

Phosphorus (P) - Macronutrients

In soil, phosphorus occurs almost exclusively in the form of orthophosphate. Substantial amount of P is associated with the soil organic matter. The major P-containing ions in soil solutions are HPO2-4 and H2PO4. Roots are capable of absorbing phosphate from solution low in phosphate content. The phosphate content of roots and xylem sap is about 100-1000 fold higher than that of the soil solution. This shows that phosphate is absorbed by plants against a very steep concentration gradient. Phosphate is highly mobile in the plant and can be translocated in upward or downward direction. The inorganic form of phosphate found in plants are orthophosphate and to a minor extent, pyrophosphate. The organic form of phosphates are compounds in which the orthophosphate is esterified with hydroxyl groups of sugars and alcohols or bound through a pyrophosphate bond to another phosphate group. You know that phosphorylated sugars and alcohols are the major intermediary compounds of metabolism.

Phosphate is also present in phospholipids. The nucleotide phosphates - ATP, UTP, GTP, CTP supply energy to various endergonic processes including active ion uptake and the synthesis of various organic compounds. Another important phosphorus containing compound is phytin which is mainly found in seeds. It is Ca or Mg salt of Phytic acid and is formed during seed formation. Phytic acid is the hexaphosphoric ester of inositol. Immediately after pollination there is an increase in P transport towards the developing seeds. Phosphorus in the phytin of seeds is regarded as a P reserve. During seed germination phytin is mobilised and converted into other phosphate forms that are needed in the metabolism of young plants. Plants suffering from P deficiency are retarded in growth. In cereals tillering is reduced. Generally, the symptoms of P deficiency appear in the older leaves which become darkish green in colour. The stems of many annual plant species suffering from P deficiency develop reddish colour due to enhanced formation of anthocyanin pigments.

Posted Date: 1/17/2013 2:49:08 AM | Location : United States







Related Discussions:- Phosphorus (p) - macronutrients, Assignment Help, Ask Question on Phosphorus (p) - macronutrients, Get Answer, Expert's Help, Phosphorus (p) - macronutrients Discussions

Write discussion on Phosphorus (p) - macronutrients
Your posts are moderated
Related Questions
Define Functions of selenium in humans? Until recently, the only known metabolic role of selenium in humans was as a component of glutathione peroxidase which along with vitami

Q. Doppler evaluation for constrictive pericarditis ? 2D Echocardiography and Doppler evaluation can provide valuable clues to the presence of constrictive pericarditis. M-Mo

Passage of Pollen Tube In cotton, the pollen produces a tube within an hour which grows on the surface of the stigmatic hairs, and then between the cells of the stigma at the

explain the relationship between the terms.. Inducer,activation transcription factor,enhancer

Explain the Protein Deficiency? One of the most common nutritional disorders in the world today is the deficiency of protein. Both adults and children are affected, as the popu

If we were to completely eliminate one group of marine organisms from ocean, which would most likely be fatal to Marin fish populations? Elimination of: a) Starfishes b) Dia

What is the function of the myelin sheath? Do all axons present a myelin sheath? The function of the myelin sheath is to get better the safety and speed of the neural impulse t

Q. What is Hydrogenqted Fat? All vanaspati preparations are the result of hydrogenation of oils, where unsaturated fat is converted to saturated fat for its favour and long she

Define Spiral cleavage in brief. Pattern of cell division in the developing embryo where products of the cell divisions shift by rotating either counterclockwise or clockwise s

Locomotion in Annelida Before we discuss the details of locomotion in annelids, we have to recapitulate the major subdivisions of the phylum Annelida. Phylum Annelida contain