Are chlorophylls good indicators of nitrogen and phosphorus levels?¹

This study was supported by a grant from the Council of Agriculture and Fish of the Andalusian Regional Government, and by the Centro de Investigacion y Desarrollo Hortícola La Mojonera in Almeria (Spain).

Abstract

Aubergine plants (Solanum melongena cv. Bonica) were grown under controlled greenhouse conditions on a soil substrate supplied with organic fertilizers (15 kg/m²) mixed with calcium sulfate (CaSO₄ at 500 g/m²), with different doses of nitrogen (N as N₁ = 15, N₂ = 22.5, N₃ = 30 g/m²) in the form of ammonium nitrate (NH₄NO₃), and phosphorus (P as P₁ = 24, P₂ = 36 g/m²) as phosphorus acid H₃PO₄). Plants were sampled every 15 days, and the pigments chlorophyll a, chlorophyll b, total (a+b) and ratio (a/b), carotene, licopene, and anthocyanins were determined in the leaves. The results showed that increases in rhizosphere N led to increases in foliar concentrations of chlorophyll a and b, both individually and as total chlorophyll, independently of the dose of P applied. Total chlorophyll concentrations were directly correlated with the level of P fertilization. Carotene and licopenes reflected the influence of increasing doses of N, whereas P did not affect these pigments. Anthocyanin levels were affected by both N and P.

Notes

This study was supported by a grant from the Council of Agriculture and Fish of the Andalusian Regional Government, and by the Centro de Investigacion y Desarrollo Hortícola La Mojonera in Almeria (Spain).

Department of Plant Biology, University Polytechnic School of Technical Agricultural Engineering, E‐04120, Almeria, Spain