Photoinhibitory printing on leaves, visualised by chlorophyll fluorescence imaging and confocal microscopy, is due to diminished fluorescence from grana

Abstract

By analogy with the starch printing technique, it was hypothesised that photoinhibition could be used to print images on leaves that would be invisible to the eye, but easily revealed by chlorophyll fluorescence imaging. We first illustrate the process of chlorophyll fluorescence printing on leaves of the shade plant, Cissus rhombifolia, using photographs of artefacts from starch printing experiments in the laboratory of Molisch. We then use portraits of current leaders in chlorophyll fluorescence research to demonstrate the stability of these images in living tissues. Text printing from microfilm of Ewart’s pioneering studies in photoinhibition shows the resolution of the method with the fixed-focus, portable, imaging system used here. The stability of images, as well as quenching analysis of images and of leaves, suggests that localised photoinactivation, rather than sustained photoprotection, is responsible for the detail displayed by fluorescence printing. Electron micrograph positives of stained thylakoids can be printed to create an illusion of what is imagined to be the source of chlorophyll fluorescence at the membrane level. Individual chloroplasts in adjacent cells under the grid pattern of granal stacks printed on leaves were also examined using a confocal microscope. Compared with chloroplasts in the shaded parts of the grid, those in the photoinactivated parts of the grid show greatly reduced chlorophyll autofluorescence. Moreover, these chloroplasts have lost the localised bright fluorescence from grana. Comparisons of fluorescence yields show that relative chlorophyll autofluorescence from grana observed in the confocal microscope parallels that determined in leaves. Our experiments provide direct visual evidence that fluorescence from grana is lost following photoinactivation of photosystem II in vivo.

From ecophysiology to phenomics: some implications of photoprotection and shade–sun acclimation in situ for dynamics of thylakoids in vitro

“…Identification of these inactivated but dissipative centres with particular pigment containing intermediates of the D1 repair cycle is a challenge, but further astonishing technical advances [64] show that photoinhibition, presumably some of it involving photoinactivation accompanied by protein phosphorylation, mobilizes a significant population of Chl protein complexes in the D1 repair cycle within 10 min. However, our experiments show such processes must continue for days and weeks during acclimation in vivo; photoinhibition images printed on shade leaves of Cissus remained clearly visible by Chl fluorescence imaging for at least 10 days in laboratory light [65].…”

Chlorophyll a fluorescence induction: a personal perspective of the thermal phase, the J–I–P rise

“…In general, various fluorescence kinetic techniques, developed recently, have begun to provide both qualitative as well as quantitative information on a large variety of photosynthetic events. There are numerous applications in very different areas, from fluorescence analysis under field conditions (Logan et al 2007;Cessna et al 2010) to aquatic sciences (Kolber et al 1998;Schreiber 1998;Suggett et al 2010), from screening mutants (Codrea et al 2010) to cellular and molecular analysis (Xu et al 1990;Oxborough and Baker 1997;Schreiber 1998;Goth et al 1999;Osmond et al 1999;Snel and Dassen 2000;Küpper et al 2000), ultimately reaching planetary dimensions through remote sensing methods (Flexas et al 2002;Moya and Cernovic 2004;Kolber et al 2005).…”

Our Eclectic Adventures in the Slower Eras of Photosynthesis: From New England Down Under to Biosphere 2 and Beyond

“…But nothing was quite so much fun as the art of secret photoinhibitory printing (129). Marianne Popp had allowed me to take a few photos of the collection of starch prints made by Molisch at the University of Vienna about a century ago.…”