Fluorescência e teores de clorofilas em abacaxizeiro cv. pérola submetido a diferentes concentrações de sulfato de amônio

Abstract

The present research aimed to analyze chlorophyll a fluorescence emission as well as chlorophyll levels in Ananas comosus (L. Merril) cv Pérola grown under greenhouse conditions and submitted to four concentration of nitrogen, through addition or not of ammonium sulphate according to the following treatments: T0 = 0.000; T1/2 = 0.015; T1 =0.030; and T2 = 0.060 g/kg soil. Determinations of minimum (F0), maximum (Fm), variable (Fv), and terminal (Ft) fluorescence and maximum photochemical efficiency (Fv/ Fm) of dark-adapted leaves were realized during the day, five days after the second application of ammonium sulphate, carried out 120 days after the transplant. The results showed that the addition of ammonium sulphate affected variable and maximum fluorescence, but not minimum and terminal fluorescence neither the photochemical efficiency. There were significant alterations in relation to the time of the day in which the fluorescence was read. Differences in leaf chlorophyll concentration were significant among treatments in relation to variations of ammonium sulphate concentration, with increase for chlorophyll a, total and to the ratio chlorophyll a/b, but not for chlorophyll b.