Phosphorus Metabolism and Yield Response to Increases in Nitrogen−Phosphorus Fertilization:  Improvement in Greenhouse Cultivation of Eggplant (Solanum melongenaCv. Bonica)

Abstract

The effect that application of nitrogen−phosphorus (NP) rates exerts on some parameters of phosphorus metabolism in eggplant (Solanum melongena cv. Bonica) was studied. All plants were grown under controlled conditions in an experimental greenhouse. The treatments consisted of the combination of three rates of N in the form of KNO3 (N1 = 15 g m-2; N2 = 22.5 g m-2; and N3 = 30 g m-2) together with two rates of P in the form of H3PO4 (P1 = 24 g m-2 and P2 = 36 g m-2), for a total of six treatments. The results obtained show a positive effect of NP fertilization on the nutritional status of P in the plants, clearly reflected in the response of bioindicators of the P (acid phosphatase activity and carbohydrates). The plants treated with N3P2 registered greater integration or assimilation of inorganic P to organic P, a fact that may be related to the maximum total and commercial yield in these plants and minimum noncommercial yield. Keywords: Solanum melongena L.; NP fertilization; phosphorus metabolism; bioindicators

Metabolism and Efficiency of Phosphorus Utilization During Senescence in Pepper Plants: Response to Nitrogenous and Potassium Fertilization

“…Acid phosphatase activity (APA) is one of the most commonly used bioindicators of the nutritional status P, and more specifically of inorganic P (18,19). In the present study, the APA activity did not respond significantly to the different N fertilizations, with maximum activity in highest levels of N fertilization ( Table 2).…”

“…Acid phosphatase activity (APA) assay was determined according to Besford (17), Ruiz et al (18), and López-Cantarero et al (19). Fresh matter was homogenized with 0.1-M sodium acetate buffer, and then centrifuged at 30,0006g.…”

“…Total P was analyzed by the vanadomolybdophosphoric colorimetric method at 430 nm (19,22). Total P was analyzed by the vanadomolybdophosphoric colorimetric method at 430 nm (19,22).…”

“…In the resulting mineralized fractions, P was determined by vanadomolybdophosphoric colorimetric method at 430 nm (19,22,24).…”

Soil Testing and Plant Analysis Relationships for Irrigated Chile Production

“…However, N availability strongly influences P absorption. Research on eggplant growth showed that an increase of N fertilization, when combined with P, may cause the plants to be able to change inorganic P to organic P at higher rates, leading to higher yields (Lopez-Cantarero et al, 1998). Phosphorus acquisition is also a function of a healthy root system (Adalsteinsson and Jensen, 1989).…”