Addition Of NH4NO3 Research Articles

A Physiological Effect of Nitrogen on Phosphorus Absorption by Corn1

AbstractA series of soil and solution experiments were conducted to study the mechanism responsible for the increased P absorption which occurs when N is added to a P fertilizer band.The addition of (NH4)2SO4 or NH4Cl to a pellet P‐32 labelled, concentrated superphosphate placed 0.5 inch to the side of a corn root greatly increased the labelled P content of the plant tops. The addition of KNO3 reduced the P content of the tops when compared to concentrated superphosphate only. When the pellets consisted of phosphate only or phosphate plus KNO3, labelled P accumulated to high levels in the root as revealed by autoradiographs. No such accumulation occurred in the presence of NH4+ ions.The addition of NH4NO3 to a nutrient solution increased the transfer of P through a 1‐inch segment of a corn root exposed to the solution, but did not influence the accumulation in the root.It was concluded that the NH4+ ion has a specific influence on the transfer of P across the root symplast to the xylem.

Possível causa do insucesso de se cultivar cafeeiros adultos em soluções nutritivas do tipo Hoagland

SUMMARY Since 1946 several attempts have been made to grow coffee plants ( Coffea arabica L. var. bourbon (B. Rodr.) Choussy) in Hoagland's nutrient solution. Growth of the plants is quite satisfactory in the early stages, but a rather sudden decline followed by death usually occurs when they start flowering at the age of 3 or 4 years. Preliminary observations made following the addition and withdrawal of NH4NO3 and KCl (0,125 g/l each salt) to nutrient solutions in which coffee trees at the critical age were growing show r ed a correlation between the addition of these salts and a satis­factory growth of the plants. These observations suggested that the decline of coffee plants growing in Hoagland's nutrient solution when they begin to flower might result from an insufficiency in the reducing power of the roots during this period. In this case the roots would be unable to use the nitrates and nitrites that would thus become toxic to them. This possibility is being further investigated.