Application of fluorescent transients to indicate nutrient deficiencies in a microalga Nannochloropsis oceanica

Abstract

Here we studied the effects of nutrient deficiency, focusing on Ca, N, S, Mg, Fe, on photosynthetic performance of Nannochloropsis oceanica to determine the abilities of fluorescence transients to detect nutrient limitation. We conducted a two-level (replete/deplete) fully factorial experiment for each of 5 nutrients and found different responses to nutrient limitation. A potential indicator of N limitation was trapped energy per reaction center (TRO/RC), as the synthesis of photosynthetic reaction center (RC) declined under N deficiency and eventually the ratio of TRO/RC increased. Photosystem II performance measured by performance index (PIABS) was not compromised under Fe, S and Mg deficiency, whereas the impact of Ca and N was critical. Although interactive nutrient interactions on photosynthetic parameters were observed, relationships were established between net reaction closure (MO) and Mg; dissipated energy flux per RC (DIO/RC) and S; and average quantum yield of photochemistry (ΦPav) and Ca.