Evidence map›Paper›PMID 40906228›Full record

ArticlePhotosynthesis research2025

A practical guide to long-term field PAM chlorophyll fluorescence measurements: setup, installation, data processing with R package 'LongTermPAM' and interpretation.

Chao Zhang, Erhard E Pfündel, Jon Atherton, Juho Aalto, Jia Bai, Toivo Pohja, Paulina A Rajewicz, Albert Porcar-Castell

Abstract read
In one paragraph

Article in Photosynthesis research, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

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0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Chao ZhangOptics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, 00014, Finland.
Erhard E PfündelHeinz Walz GmbH, Eichenring 6, D-91090, Effeltrich, Germany.
Jon AthertonOptics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, 00014, Finland.
Juho AaltoInstitute for Atmospheric and Earth System Research (INAR)/Forest Sciences, University of Helsinki, Helsinki, 00014, Finland.
Jia BaiOptics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, 00014, Finland.
Toivo PohjaHyytiälä Forest Station, Hyytiäläntie 124, Korkeakoski, 35500, Finland.
Paulina A RajewiczOptics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, 00014, Finland.
Albert Porcar-CastellOptics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, 00014, Finland. joan.porcar@helsinki.fi.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Pulse-amplitude modulated (PAM) chlorophyll fluorescence (ChlF) measurements provide a non-invasive method to study the regulation of the light reactions of photosynthesis in situ. PAM ChlF contributes also to the advancement of the interpretation of long-term observations of remotely sensed solar induced fluorescence by revealing the mechanistic connection between ChlF and photosynthetic function. However, long-term field PAM ChlF measurements remain uncommon due to challenges associated with the outdoor environment, instrument installation and maintenance, or data processing and interpretation. We here provide guidelines and recommendations to support long-term field installation of PAM ChlF systems, including the design of specialized field installation supports. We also introduce a dedicated R-package (LongTermPAM) to help users filter and analyse long-term data. Methods are demonstrated using two long-term datasets obtained with a MONI-PAM system (Monitoring PAM, Walz GmbH, Germany) on Scots pine and Norway spruce in a boreal forest. The LongTermPAM R-package helped filter spurious observations caused by dew, ice or snow, permitting calculation of photochemical (PQ) and non-photochemical quenching (NPQ) parameters and their associated yields. Finally, we illustrate how PQ and NPQ regulate the relationship between ChlF and photochemical yields, and discuss how variations in leaf PAR absorption, energy partitioning between photosystems II and I, and the contribution of photosystem I to the total ChlF signal can influence the interpretation of PAM ChlF, emphasizing the value of complementary measurements to capture variability in these factors. Although based on our experience with the MONI-PAM system in a boreal environment, most issues hereby addressed can be broadly applied to other long-term PAM monitoring systems and environments.

Indexed as

ChlorophyllFluorescencePhotosynthesisPiceaPinus sylvestrisPlant LeavesChlorophyllMonitoring PAMNon-photochemical quenchingNorway sprucePhotochemical quenchingScots pineSeasonality of photosynthesis

Identifiers

PMID40906228
PMCPMC12411321

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.