Chlorophyll fluorescence measurements in Satakunta Experimental site

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Dataset Abstract

Productivity is great in forests with a capacity to intercept incoming radiation and harness its energy efficiently. Thus, understanding the relationships between forest diversity, tree canopy biomass and photosynthetic parameters is central to predicting how diversity will affect a key ecosystem function (i.e., productivity). Specific hypotheses to be tested: I) higher tree species diversity enables greater exploitation of light within forest canopies due to niche partitioning, increasing photosynthesis and primary production (NPP); II) photosynthetic acclimation (ecological resilience to changing environmental factors) on singular species may vary according to the varying ecological conditions, but is supposed to be maintained at plot level in mixed population (interaction of different species-specific behaviors). Photosynthetic acclimation was measured with chlorophyll fluorescence, by applying fast and reliable techniques based on the fast kinetics of the chlorophyll fluorescence induction in dark adapted leaves. This method is called JIP-test and is based on the measure of the variable fluorescence at different steps of the induction.
In July 2011 chlorophyll fluorescence were performed at Satakunta (Finland) Experimental site. Here plots 20mx20m were established in 1999, in which different species mixture were achieved by mixing the species tree by tree. Chlorophyll fluorescence measurements were done in leaves and needles south exposed, at the top of canopy, attached to the twigs/twiglets to keep them hydrated. At Satakunta twig sampling was performed in the morning (09:00 – 13:00) with extension loppers. The twigs (and leaves) were collected from 5 trees per specie per plot, randomly distributed inside the plot. The measurements were replicated in 5 leaves per tree randomly selected in the branchlets. In evergreen conifers chlorophyll fluorescence measurements took in current year needles (i.e., needles sprouted in 2011, 1-year needles). The branchlets, just collected from each tree, were put in black plastic bag (labelled with data ID plot number, and ID tree number) and stored at ambient temperature, avoiding sub exposure of the bags. After some hours of dark adaptation of the samples (minumum 4-5 hours) the measurements were taken in a darkened room at the Satakunta Environmental Research Centre (Reposaari). Measurements were taken by HandyPea fluorimeter (direct or prompt fluorescence).

Dataset Design

We performed the chlorophyll fluorescence in 19 plots of area 1 (near Pormakku) of Satakunta Experimental site. We used 5 trees per specie per plot, earlier selected for isotopic and nitrogen analysis. For each tree we collected one twig south-exposed in the top of the a canopy. 5 leaves randomly chosen for twig were used for the chorophyll fluorescence measurements.

Spatial Extent

In July 2011 chlorophyll fluorescence were performed at Satakunta (Finland) Experimental site. Here plots 20mx20m were established in 1999, in which different species mixture were achieved by mixing the species tree by tree. Chlorophyll fluorescence measurements were done in leaves and needles south exposed, at the top of canopy, attached to the twigs/twiglets to keep them hydrated. At Satakunta twig sampling was performed in the morning (09:00 – 13:00) with extension loppers. The twigs (and leaves) were collected from 5 trees per specie per plot, randomly distributed inside the plot. The measurements were replicated in 5 leaves per tree randomly selected in the branchlets. In evergreen conifers chlorophyll fluorescence measurements took in current year needles (i.e., needles sprouted in 2011, 1-year needles). The branchlets, just collected from each tree, were put in black plastic bag (labelled with data ID plot number, and ID tree number) and stored at ambient temperature, avoiding sub exposure of the bags. After some hours of dark adaptation of the samples (minumum 4-5 hours) the measurements were taken in a darkened room at the Satakunta Environmental Research Centre (Reposaari). Measurements were taken by HandyPea fluorimeter (direct or prompt fluorescence). The samping and the measurements were carried out by Martina Pollastrini and Filippo Bussotti.

Taxonomic Extent

5 tree species (total number of sampled tree/specie): Betula pendula (45), Picea abies (44), Alnus glutinosa (35), Pinus sylvestris (43), Larix sibirica (40)

Measurement Circumstances

Overall very warm, sunny weather

Data columns available in the raw data part of this dataset

ID plot
Satakunta plot number of Area 1. Unique number ascribed to each plot; Datagroup description: plot number identification
Data group: Satakunta Plot Id
Values
17
1
21
15
18
Mixture level
Mixture level
Data group: Satakunta Plot Id
Values
5
1
3
2
Species combination
Code used: PA - Picea abies; PS - Pinus sylvestris; LS - Larix sibirica; BP - Betula pendula; AG - Alnus glutinosa
Data group: Satakunta Plot Id
Values
BP
AG
BP-AG
LS
LS-BP-AG
ID tree
Number of sampled trees for leaf sampling (isotopic analysis, carbon and nitrogen analysis, fluorescence measurements)
Data group: Tree species id
Values
0304
0406
0405
0404
0305
Species
name of the species
Data group: Tree species
Values
Picea abies
Larix sibirica
Pinus sylvestris
Betula pendula
Alnus glutinosa
M0
Approximated initial slope (in ms-1) of the fluorescence transient normalized on the maximal variable fluorescence; Datagroup description: Approximated initial slope of the fluorescence transient
Unit: ms-1
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.38448000000000004
0.39249999999999996
0.43462
0.4105
0.35434
VJ
Variable fluorescence intensity at time 2 millisecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1). It is expressed in arbitrary unit.; Datagroup description: Variable fluorescence intensity at time 2 millisecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1). It is expressed in arbitrary unit.
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.28978000000000004
0.29138
0.26846000000000003
0.27918
0.28937999999999997
VI
Variable fluorescence intensity at time 30 millisecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1). It is expressed in arbitrary unit.; Datagroup description: Variable fluorescence intensity at time 30 millisecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1). It is expressed in arbitrary unit.
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.58698
0.6155333333333333
0.50098
0.65066
0.63718
Sm
Normalized area above the fluorescence induction curve. It is expressed in arbitrary unit and calculated as SM = Area/ (FM-F0), where F0 is the minimal fluorescence intensity, measured at 50 microsecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1).; Datagroup description: Normalized area above the fluorescence induction curve. It is expressed in arbitrary unit and calculated as SM = Area/ (FM-F0), where F0 is the minimal fluorescence intensity, measured at 50 microsecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1). Normalized area above the fluorescence induction curve
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
12.876475
12.349100000000002
13.132800000000001
11.80728
11.5299
FV/FM
Maximum quantum yield of primary photochemistry in dark-adapted state. Expresses the probability that an absorbed photon will be trapped by the PSII reaction centre; Datagroup description: Maximum quantum yield of primary photochemistry in dark-adapted state. Expresses the probability that an absorbed photon will be trapped by the PSII reaction centre
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.7488600000000001
0.7562200000000001
0.74974
0.7587
0.7212799999999999
PIabs
Performance index (potential) for energy conservation from photons absorbed by PSII to the reduction of intersystem electron acceptors; Datagroup description: Performance Index (potential) from photons absorbed
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
12.63384
14.640933333333335
12.79538
14.776039999999998
14.01112
PItot
PItot is the performance index for energy conservation from photons absorbed by PSII to the reduction flux (RE) of PSI end acceptors. This parameter is calculated from other parameters of the fluorescence induction curve analysis. It is expressed in arbitrary unit.; Datagroup description: PItot is the performance index for energy conservation from photons absorbed by PSII to the reduction flux (RE) of PSI end acceptors. This parameter is calculated from other parameters of the fluorescence induction curve analysis. It is expressed in arbitrary unit.
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
10.454506512648804
10.249830614384052
10.189779582297895
10.43980538513319
10.431453632531358