Viewpoint: Avoiding common pitfalls of chlorophyll fluorescence analysis under field conditions

Abstract

The determination of chlorophyll fluorescence emission is a powerful tool for assessing the status of PSII and the allocation of absorbed light to photosynthesis v. photoprotective energy dissipation. The development of field-portable fluorometers has enabled growing numbers of scientists to measure fluorescence emission from plants in diverse field settings. However, the ease of operation of contemporary fluorometers masks the many challenges associated with collecting meaningful and interpretable fluorescence signals from leaves exposed to relevant environmental conditions. Here, we offer methodological advice aimed at, but not limited to, the non-specialist for the proper measurement of fluorescence parameters, with an emphasis on avoiding common errors in the use of fluorescence under field conditions. Chief among our suggestions is (1) to delay use of automatically calculated fluorescence parameters, presented by the instrument software, until raw data ‘traces’ have been carefully inspected to ensure the integrity of findings, and (2) to combine chlorophyll fluorescence analysis, as a rapid, preliminary method of assessing plant responses to stress, with additional methods of characterising the system of interest (e.g. gas exchange, foliar pigment composition, thylakoid protein composition).

Insights into the Positive Effect of Pyraclostrobin on Sugarcane Productivity

“…Carotenoids act as accessory pigments, playing a key role, together with xanthophylls, in photoprotection and acting directly on the thermal dissipation of energy [30]. The increase in this pigment observed five days after the application of pyraclostrobin in the cultivar, RB92579, (Table 2) may indicate an increasing tolerance of these plants to an excess of luminosity.…”

Fluorescence as a Tool to Understand Changes in Photosynthetic Electron Flow Regulation

“…Whereas, qT is currently unknown in diatoms (Owens 1986) and brown macroalgae (Fork et al 1991), and of only moderate importance in higher plants and dinoflagellates (Hill et al 2005), yet highly developed in some green microalgae and cyanobacteria (Finazzi 2005;Mullineaux and Emlyn-Jones 2005). Amongst the three components of NPQ, qE has a major influence on the Chl a fluorescence signal under normal growth conditions (Logan et al 2007; see also Chapter 7). The interpretation of qE is possibly the most complex of the NPQ components, as it is linked to faster regulation of photosynthesis than qT and qI with most organisms, especially under naturally fluctuating environment (Lavaud 2007).…”

Decreased Photochemical Efficiency of Photosystem II following Sunlight Exposure of Shade-Grown Leaves of Avocado: Because of, or in Spite of, Two Kinetically Distinct Xanthophyll Cycles?

“…An early turning point was marked by Björkman and Demmig-Adams (1994) with their conclusion: "Responses that in the past were thought to be indicative of photoinhibitory damage (reduced photon yield of CO 2 uptake and oxygen evolution and quenching of maximum fluorescence yield) in many cases now appear to be reflections of photoprotective processes." Although the need for simultaneous evaluation of these two principal responses to excess light has been recognized for some time (Osmond, 1994;Logan et al, 2007), surprisingly few comprehensive studies have been published. Photoinactivation of PSII centers, in spite of full expression of xanthophyll-dependent nonphotochemical quenching (NPQ), has been observed in model plants such as wild-type Arabidopsis (Arabidopsis thaliana; Russell et al, 1995;Bailey et al, 2001), in some strains of very high-light-resistant mutants of Chlamydomonas reinhardtii (Förster et al, 2001(Förster et al, , 2005, and evaluated in wild plants from contrasting light environments (Thiele et al, 1996(Thiele et al, , 1997 Shade leaves in canopies of tropical species such as Inga spp.…”